CatalystJournal of the Amateur Yacht Research Society

Number 20 April 2005

APRIL 2005 1

Catalyst

Features

6 Rushing About on Ivanpah 2004Jerry Selness

10 Elementarry - a 7.5 m x 4 m foldingsports, daysailing, or camping proa

Rob Denney &Michele Balharry

14 The Wave RockerKen Upton &

William Groombridge

18 The Power Alternating Sailing(PAS) Principle and the Mill-PropPrinciple

Peter Sharp

Regulars

2 Kites & Sailing Records3 News - Concept Boat, RIBEX

5 Letters - Help wanted, Boat for sale,Downwind as fast as you like

26 Notes from Toad Hill - A Suggestion,and an Offer

Frank Bailey

28 Catalyst Calendaribc John Hogg award

Cover PhotoMark Stephens & Rob Denney

sailingElementarry

in Coffs Harbour, NSWAustralia

Photo Michele Balharry

2 CATALYST

CatalystJournal of the

Amateur Yacht Research Society

Editorial Team �Simon FishwickPeter WestwoodSheila Fishwick

Specialist CorrespondentsAerodynamics�Tom Speer

Electronics�David JollyHuman & Solar Power�Theo Schmidt

Hydrofoils�George ChapmanInstrumentation�Joddy ChapmanIceboats & Landyachts�Bob Dill

Kites�Dave CulpMultihulls�Dick Newick

Speed Trials�Bob DownhillSteam Power�Lord Strathcona

Structures�Keith BurgessWindmills & Turbines�Jim Wilkinson

Catalyst is a quarterly journal of yacht research,design, and technology published by the AmateurYacht Research Society, BCM AYRS, LondonWC1N 3XX, UK. Opinions expressed are theauthor�s, and not those of AYRS. AYRS alsopublishes related booklets.Contributions are welcome from all. Email themto Catalyst@ayrs.org, or send (at your risk)disks or typed copy with illustrations to theSociety�s office. AYRS can take no responsibilityfor loss or damage.AYRS subscribers receive both Catalyst and thebooklets. Subscription is UK£20 or US$30 perannum for a Full Member, £10 or $15 forstudents and retired members. Subscriptionrequests and all other queries to be sent to theAYRS Office, BCM AYRS, London WC1N 3XXUK, phone/fax +44 (1727) 862 268 or email:office@ayrs.orgAYRS is a UK Registered Educational Charity(No 234081) for the furthering of yacht science.

Website: http://www.ayrs.org

© 2005 Amateur Yacht Research SocietyBCM AYRS, London WC1N 3XX, UK

All Rights ReservedISSN 1469-6754

Kites & Sailing RecordsOn 8th February, the International Sailing Federation (ISAF)

Executive meeting appeared to ban kite-powered craft fromcompeting for any sailing records. Not unexpectedly thisprovoked some protest. As a result the World Sailing SpeedRecord Council (WSSRC) issued the following statement:

�To clarify the World Sailing Speed Record Council position ... kiterecords will continue to be ratified by the WSSR Council in that divisionand kite speed sailing events will be observed and monitored as normal...

However, ISAF have stated that, at present, a claim on the outrightWorld Sailing Speed Record by a kite sailboard would not be endorsed.This represents no change from the current position.�

So kiteboarders can set their own records, but even if theygo faster than anyone has before, (and they are getting veryclose) they will not be recognised by ISAF as holding theworld record.

Frankly to us in AYRS this is short-sighted; and it showsmore than anything else how much of a gulf there is betweenthe ISAF Executive and those who spend their time makingboats go faster. No doubt ISAF will change their position intime, and I know that the WSSRC are working to that end, butin the meantime it is simply something to be borne.

AYRS� own position is that, as sponsors of the Weymouth& Portland Speedweek, which is held every October, we willpress for the continued total inclusion of kite-powered craftand boards within the world Speed Sailing Records system,and will ensure that kite power continues to be welcome atSpeedweek.

As the Secretary of the Danish Sailing Federation wrote inFebruary - There is absolutely no difference between the current situationwith Kitesurfing, and the situation with windsurfing in the 1970�s andbeginning of the 1980�s. At that time windsurfing was something manyof the traditional sailors found was not �sailing�. Of course it was � andstill is. ISAF took care of this new exciting discipline and nationalsailing associations all over the world followed the lead. Today, nobodywould dare to say that windsurfing is not sailing, and it has been on theOlympic programme since 1988.

To you our members we would say that if you are in anyway involved with organised kitesailing in your own country, orwith your national Sailing Authority, then please press for achange in ISAF�s stance. As far as we can tell, it has no realrhyme or reason behind it, just a total lack of understanding.

If you are professionally involved in kite sailing, either ascompetitor, teacher, marketing or manufacturing, then youshould already know that Dave Culp is organising a world-wide trade association for kite sailing � an independentorganization whose sole purpose is to lobby local, national andinternational governing bodies for the cause of all those whosail with kites, be they �kitesurfers�, �kite spinnaker� users, oreven �commercial kite vessel operators�. You can contact himby email at <dave@kiteship.com>.

Simon FishwickEditor

APRIL 2005 3

News & Views

Entrants to the Concept Boat2005 competition will be asked todesign a boat under the theme�Boating for all�. The internationalcompetition runs annually and hasbeen created to foster an interestin designing boats of the futurewhilst emphasising the value ofinnovation and creativity. Thecompetition covers bothrecreational and commercial craft,and each year has a differenttheme.

To make the competition evenmore appealing and accessible toall, this year, for the first time, thecompetition has been divided intothree key categories:• Concept and design -

Detailed designs that have movedbeyond pure concept into adeveloped concept• Pure Concept � a simpleillustration of their concept boatwith a brief written summary• UK Schools � for teams ofschool children to develop theirideas into concepts, as part of thenational curriculum

In addition to the traditionalemphasis of the competition,which continues in the �Conceptand design� category, the newcategories enable entrants toconvey simply the concept oftheir boat through a simpleillustration, without the need forsupporting technical specifications.

Supported by famous designer,Wayne Hemingway, it is hopedthat the 2005 Concept Boatcompetition will stimulate furtherinterest in forward thinking,innovative boat design.

Hemingway and his panel ofjudges will be looking for practical,original designs that create a safe,usable yet stylish vessel of thefuture. Key design features thejudges are looking for include:• low or moderate cost• suitable for group activities• a kit for easy assembly• encourage and appeal to youthparticipation• a new boat for sea cadets orsimilar• and a new racing concept

Concept Boat Design Competition 2005Cult designer Wayne Hemingway is to front the 2005 Concept Boat Competition, organised

by the British Marine Federation with support from the Royal Institute of Naval Architects.Shortlisted entrants will have

their designs on display at nextSeptember�s Southampton BoatShow. The winners will have aprototype of their model madeand displayed at the 2006 LondonBoat Show where they will also beawarded their prizes. In eachcategory there will be two prizesand in addition there will be anoverall winner of Concept Boat2005 chosen from the winningentry of each of the threecategories: �Concept and Design�:winning entry £2500 and runnerup £1000; �Pure Concept�: winningentry £1000, runner up £500; andthe Schools. The winner of theoverall competition will receive anadditional £2000.

Entries to the UK schoolcategory must be received by theend of April 2005 and for otherentries by the end of May 2005.For full terms and conditionsplease visit www.conceptboat.com.

Rigid Inflatables Conference & Exhibition 2 - 3 June 2005, Cowes Yacht Haven, UKThe Rigid Inflatable Boat, or

RIB as it is more commonlyknown, has made a significantimpact on many kinds of smallboat operations over the last threedecades. Its advantages are wellproven in practice and a thrivingindustry is now established aroundthese unique craft.

The conference, organised bythe Royal Institution of NavalArchitects, will be held in the run-up to, and on the first day of�RIBEX 2005�. This is a major

three-day exhibition organised byRIB International magazine. Thiswill attract professional operatorsas well as RIB builders and designersfrom around the world. The venuewill be in the newly built conferencefacilities at Cowes Yacht Haven.

Since RINA�s last RIB conferencein 1998, the technology has advancedconsiderably: the trend towardslarger and faster boats continues,and there are a multitude ofvariations on the original RIBconcept.

This conference will examinetopics relating to the design andoperation of RIBs including thefollowing topics:

Design & Construction:Engines & Propulsion:Operations:Rules & regulations.

RINA�s Conference Departmentcan be contacted on

Tel: +44 (0)20 7201 2401Fax: +44 (0)20 7259 5912Email: conference@rina.org.uk

4 CATALYST

News & Views - Letters

I have been offered theopportunity to demostrate theprinciples of single-oared scullingat the Jan 06 London Boat Show.To this end I have designed aworking model of a raft of about20cm beam x 40cm length for atable-top demonstration.

Some recipients of this messagewill need no reminding of howinept I can be with things practical,and in any case I hav�n�t access toeven simple hand tools duringthaat greater part of the year whenI work abroad. So I am lookingfor people to help me, at least withthe critical components. Ofcourse, I don�t expect this fornothing, and am happy to offer

Boat for SaleThose kind enough to

remember my talk in London tothe AYRS last November willknow someting of MERCIAMAID ; she is my Tucker-designed/Peter Nicholson-built�Broads Cruiser�, as they describeher. Although fitted with a fueltank and propellor block, she hasnever been equipped with thediesel engine around which she

Call for papers -HIGH PERFORMANCE YACHT DESIGN CONFERENCE14 - 16 February 2006 - Auckland, New Zealand

Timed to coincide with thearrival of the Volvo Ocean Racefleet in New Zealand, the secondinternational conference on highperformance yacht design will beheld in February 2006, and willshowcase the latest developmentsin yacht research from around theglobe. This conference will be avenue where naval architects,engineers, designers and

researchers can present and hearpapers on the current state of highperformance yacht and powercraft technology.

Advances in high performanceyacht design are being driven by arange of factors, includingdevelopment of new racing classesand demand for increased size andperformance of racing andcruising craft. Radical design

concepts such as innovative newhullforms, moving keels and mastsand new approaches to sails andpropulsion systems requireinnovative approaches to analysis,design and experimentalverification.

The Conference Departmentcan be contacted on

Tel: +44 (0)20 7201 2401Fax: +44 (0)20 7259 5912Email: conference@rina.org.uk

professional rates and/or ashare in the glory. �Thelabourer is worthy of his/herhire�.

January may seem a longtime away, but I shall be inthe UK only from mid-Juneto mid-September, andwould like to see the modelworking by the end of thattime. I have already madeinformal overtures to a fewpeople, and would like togive them a formal decisionas soon as I can.

Please email for detailsand drawings !

Michael Bedwell<michael_bedwell@hotmail.com>

Help Wanted

was designed. But she does havesails and rigging, both gunter andthe modified lateen rig I use oninland waterways. She also has theunique stern-sculling gear whichwas the main topic of my talk.

She is currently moored on theAvon between Bath and Bristol.Her steel hull and lack of enginemake her cheap to maintain, butshe is still an expensive investmentnow I work out of the U.K. .

Ideally, I�d like to find a partnerwho would have use of her for tenmonths of the year and whowould share costs. Alternatively ,I�d consider an outright sale. Shecost me some GBP16000 back in1996.

Please email for further details<michael_bedwell@hotmail.com>.

Many thanksMike

Mike Bedwell�s Mercia MaidPhoto © The Bath Chronicle

APRIL 2005 5

News & Views - Letters

I was intrigued by John C.Wilson�s article in the last issue ofCatalyst. I could not refute thespool-of-thread analogy shown infig. 1 and yet it seemed to defy thelaws of conservation of energy.The thread seemed to impart moreenergy to the spool than the windimparted to the sail.

Another curiosity is thedirection of rotation of the spool.The tension on the thread wouldcause the spool to rotate counterclockwise were it not for theopposing torque exerted by thesurface on the rim of the spool.The energy required to rotate thespool clockwise is clearly notdelivered by the thread. Thereforeit does not come from the sail orthe wind.

To translate the analogy to a sailcraft, a craft flying a spinnaker or akite could be made to godownwind faster than the windspeed by rapidly winching in thesheets. This would work but,unfortunately, it would not qualifyas �sailing�. The winches wouldrequire power not provided by thewind. Rule 1 states that the craftmust be propelled by the action ofthe wind only.

The concept of the inchwormis interesting and I would like tosuggest a practical, if perhapsfacetious, implementation.Suppose the craft is suspendedunder a balloon. By itself it wouldbe borne downwind at exactly thewind speed. It could be made togo faster by �rowing� it with oarshaving sails instead of blades. Thiswould propel the craft to a higherspeed on the back stroke and theoars would be feathered on theforward stroke. Once again, toexceed the wind speed requires anextra source of power provided by

the rower. The craft is not�sailing� in the sense that it ispropelled by the wind alone.

In conclusion, it is safe to saythat it is theoretically impossible to�sail� downwind faster than thetrue wind speed. A craft can sailat several times the true windspeed but not directly downwind.On any other course, however fastthe craft is sailing, the downwindcomponent of the speed cannotexceed the true wind speed. Thatis to say, you cannot beat thisrestriction by tacking downwindon very fast broad reaches.

Peter Jeffersonpjjefferson@sympatico.ca

[For a contrary view see thearticle by Peter Sharp in this issue� Ed.]

In the July 2004 issue ofCatalyst (#17) Bernard Coat anHay writes about looking for thelimits for sailboat speed. PeterJefferson writes about the 50 knotspeed �barrier� for sailboats. Anyone interested in the limits forsailboat speed would do well tostudy Chapters 9 and 10 in mybook, Primitive Benchmark: a ShortTreatise on a General Theory of Sailingwith the Limits for Sailboat Speed(ISBN 0-9671566-0-2.) Any oneinterested in achieving a 50 knotspeed with a new sailboat woulddo well to study Chapter 10 of theafore-mentioned book.

Sincerely,Jerry N. Selness

4611 Monongahela StreetSan Diego CA 92117

Self Steering GearWe have recently completed

development on a jib sheet to tillerself-steering gear.

You may be interested to take alook - www.steersman.net

Best regards,Rob Chicken

Dow Chemicals BlueStyrofoam Insulation

I came across your website thismorning and thought I�d contactyou with a view to introducing thecompany I act as product managerfor in their foam division.

The company is called PanelSystems Limited and we areEurope�s largest fabricator ofStyrofoam. We are based inSheffield, UK.

I am aware that a number ofmy existing customers thatpurchase Styrofoam are active inthe Marine Industry.

If you believe that yourmembers would be interested inhaving a direct source for ourmaterial please contact me at<gfowler@panelsystems.co.uk.>

I look forward to hearing from you.Geoff Fowler

Product Manager, Foam Division.Panel Systems Limited

Comments on �Downwind as fast as you like�

New EmailAddresses

Please note that AYRS now hasa new email address:

For the Secretary use:office@ayrs.org;

For Catalyst usecatalyst@ayrs.org

The old addresses still work forthe moment, but will slowlydisappear.

6 CATALYST

Ivanpah

On the afternoon of my arrival it seemed like thecracks had sucked up all the wind. Still a friend, BobDill, lets me use his Manta Twin land sailor to whetmy appetite for the sport.

The Manta Twin is a three wheeled, tubular,open-framed buggy craft, one wheel in the front,two in the back. The wheels are about the size of ago-kart tire. A pole mast is set behind the frontwheel and supported by side tubular frames thatextend from a point about 1/5 the way up the mast tothe rear axles each side near the rear wheel bearings.The steering is by the feet of a pilot reclining on ablack hammock like canvas seat. The pilot isstrapped in with a seat belt when under way. Thesail is triangular with the leading edge wrappedaround the mast. The rear corner is fixed atthe outboard end of a boom. The sail andboom are trimmed in and let out by arope line lead from a cross tube behindthe pilot, up to the end of theboom, to the mast, and back to thecanvas slung seat via pulley blocks,and held in one or both hands whenunder way. (See Photo)

Soon I am strapped in and readyto go. An encouraging get-startedpush from Bob starts the wheelsturning and builds a littlemomentum. Sustained movement ishard to maintain over the hardsand-clay tiles. The first afternoonon the playa the winds are reallylight. My anticipation for speeddoes not matter to the craft and thelight desert winds. Hanging my feetout on both sides, grunting andshuffling to get the buggy wheelsturning has little effect, It is afrustrating first experience, so far I

am about the only land sailor out with the manyother sailors seated in the shade next to parked RVsand tents parked on the edge of the dry lakebedsipping their mint juleps. A couple of gust-puffscome up and are enough wind to get the craft andmy heart rolling at a crawl back to the long line ofcampers and their tents.

Rushing About on Ivanpah 2004

Jerry Selness

Ivanpah is a dry lakebed in California, the shape of a sausage about 1 mile wide and 5 miles long.Mountains surround it. Lumpy hexagonal dirt tiles make up the bed itself, called the clay playa, or just theplaya. This year with little rain the tiles and playa are hard. Narrow shallow crack-like gaps run between thetiles, good places for spiders and insects to hide from the sun during the day.

APRIL 2005 7

Jerry Selness

Later that afternoon, pilot Phil Mancell fromOregon, part of the throng of land sailors gatheredon the high desert from around the world, told me�land sailors sail for the rush.� I would have to waituntil the next morning to experience the rush.

About all this afternoon and rest of the day bringis frustration, supper, and the stars at night justbefore crawling into my own tent hoping the nextmorning will bring a little more wind.

Up with the sun and outside with feet on theplaya, there is a little more wind. I can feel it and seeit in the flags flying set from poles on top of RVs.With sunglasses on, and, gloves in helmut andhelmet in hand, I stride purposefully from my littletent past a big central pow-wow-tent towards Bob�sbig RV to find him. He is circling on his bicycle infront of his RV. Seeing me coming, he stops circling,and says, �Jerry, take the Manta Twin out.� He has toorganize some races - just what I wanted to hear.

I look up at an American flag set on a pole atopof a motor home. It is flapping, flapping and flyingstraight out. A good sign for enough wind andencouragement not to hesitate, but to strike whilethe wind is hot on the high desert.

Donning helmet and gloves, being sure to bucklethe chinstrap for the motorcycle-like helmet, then,pulling the three-wheeled buggy by its mast with onehand and holding its rope-rein in the other I stepeagerly onto the playa. Soon the winds begin to tugthe Manta forward, get the wheels turning. I shift asteadying right hand to the left side frame and walk,then break into a trot beside the moving Manta Twinstill holding the rope rein in one hand. The windspull the sail and the craft rolls forward more, andfaster too. I feel like a boy walking a snorting horseby its reins (like the lad in Picasso�s painting with theboy leading a horse on the sand by the seashore.)The winds tug at the sails again and again. The go-kart-like wheels roll a little faster. I start to jog faster,right next to the tubular frame of the craft just tokeep up before taking a deep breath and leapingaboard the horse still holding the reins, trimming thesails. And away we go- �whish,� rolling on the desert.

I jump aboard hard and abruptly. The thud on thecanvas seat dislodges a big nasty black widow spiderfrom beneath the hammock-like seat. My left footleaves the steering bar, moves quickly to squish thesurprise intruder saving myself from a potentialdesert danger. Yeow. From then on, the ride getsfaster, faster, holding on to a broad reach course

across the wind and across the lakebed. The ride is alittle bumpy on the hard tiles. I glance ahead. Theother side of the lakebed is coming up quickly.Arriving sooner than later, I am a bit excited at theother side of the lake. I turn the craft straight intothe wind and stop for a breather.

Stepping on to the playa dirt once more,mainsheet in hand, I lead the Manta Twin onwardlike Lawrence of Arabia leading his camel. The winddoes its job and gets the craft rolling. This time, thewheels begin to turn, go round and round with eachfresh tug on the sail by the wind. The buggy beginsto snort and move a little faster. I jog a little fasterand jump aboard, more smoothly this time, to gowith the flow. The rope-rein is firmly in one hand;my feet stretch out and rest on the stubby steeringhandles near the mast. Toes nudge the steering barthis way and that for easy front wheel steering.Simultaneously I trim the sail slowly using bothhands and bring the boom closer to my ear, all thewhile gathering more speed�straight for a newhazard, a bunch of mini-model radio controlledyachts playing at the far North corner of the lakebed. Arriving very quickly, I fear running into themor taking their precious wind. The best choice is notto go across the wind of their racecourse but ratherto come (turn) head to wind, slow down, hop out,and start off walking again. Soon trotting, I jumpaboard smoothly, then, I gain head way and pick upspeed on a course, away from the model sailors, andaway from the line of tents, sailing smoothly towardsthe far side of the lake bed.

Nudging the craft gently downwind a bit, withoutchanging the trim on the sails, the craft�s speed picksup more, the first rush (sudden acceleration) beginsjust before the galloping front wheel tosses up apiece of brush from the desert floor straight at myhead. There is no time to duck the twig. It slamssquarely across my sunglasses and bounces off thecorner of my helmet back to the desert. I think�Jeewhiz another desert hazard escaped. Whew! Thisis fun�. Catching my breath and steering moretowards a downwind direction, at a certain point,speed begins to fall off. Heading back up to abroader reach course regains speed quickly. Runningout of dry lakebed it is time to gybe (change coursefrom one side of the wind to the other when goingdownwind.) Gybing from starboard to port tack is acalm quiet transition. The boom and sail comeacross smoothly, the sail is full, and the craft regainsspeed quickly on the new gybe course downwind.

8 CATALYST

Ivanpah

APRIL 2005 9

Jerry Selness

Glancing over the left wheel, I see the RV tents arefar to the left and leave them further behind headedfor the far side of the lakebed.

It is time to go back, head the craft upwind to getback to camp. Thinking about the light winds ofyesterday, when wearing about (like the old square-riggers going in a 3/4 circle to change tacks upwind)was the only way to tack upwind and keep the craftmoving from upwind course to upwind course Idecide today with the stronger winds to try tackingthrough the eye of the wind. On first try, turning thecraft hard slows the wheels nearly to a stop beforeattaining the opposite upwind course. Re-gainingspeed on the opposite upwind tack is slow. On thenext try I find that a technique of turning lessabruptly, maintains momentum through the eye ofthe wind, and there is still speed when the sails fillcoming out on the new tack.

The rush on the downwind course is hard to putinto words; yet, every land sailor knows what it isabout. The best I can do to describe it is this: it is thesudden transition from moving/rolling quickly toanother world of speed with the wind, man, craft,and nature, moving as one, together for a preciousmoment in time.

Having made my way back upwind, I am temptedto stay out a little longer on the playa just for therush, one more time, but decide I need to head backto the tents and get Bob�s land sailor back to himready for his afternoon racing starts. I head theManta twin quickly and swiftly for the line of tents,get there and turn head into wind just beforecrossing into the line of craft and folding chairs toavoid any spectacular crashing arrival incidents. Aftergliding to a safe stop, it is a challenge to get the craftback to its parking space.

Learning to back the Manta Twin while standingin front of it is a necessity for controlled movementalong and among seated campers, RVs, tents, othertethered craft and Manta�s turned on their sides, sailsdown against the desert floor and one rear wheelhigh. Backing the Manta Twin this way and that waybetween the many already parked craft to a parkingspot for Bob to find, is a tricky proposition with thewind blowing strong and nervous owners watchingthe show. I get the hang of it. Pull the sail in tight, tieit off on the frame, then grab the sail�s mast, turn thecraft head to wind and let the wind push itbackwards is the way to do it. I nudge the wheels alittle this way and a little that into an open areabefore tipping it gently on its side, safe and ready for

the next lad or lassie to right, steer into the openIvanpah spaces, walk next to and jump aboard �forthe rush of it.�

It is a thrilling sail for me this mid morning. Whathas Bob been doing all this time I have been havingfun with his craft? Soon I see Bob and walk towardshim with a big smile on my face and ask, �What canI do for you?� He knows just the thing for a readyvolunteer. Ho, ho, ho. The ensuing afternoon, untilsunset, is spent standing on the hot dirt tiles in themiddle of the hot playa with just enough water to sipas a volunteer scorer for rest of the high tech folksand their real fast custom race machines, togetherwith fleets of Manta Twins, Singles, Fed Vs, FiveSquares, New Zealand MiniBlokarts, and otherclasses.

Before the racing starts members of the ad hocracing committee place orange traffic control conesspread across on the desert floor to form the endsof a start and finish line and be marks for the racecourse. The race committee driving back and forthin an SUV places more cones about three milesstraight upwind at the far, far end of the playalakebed towards Arizona and Mexico. Other conesare then set straight downwind at the far, far end ofthe lakebed towards the main highway, theCalifornia-Nevada Mountains and Death Valley�sdeep desert beyond. The start finish line is situatedcrossways in the middle of the course near scorerswho keep track of the zooming land sailing craft asthey streak up and down the course, passing throughthe official line when making each round of the racecourse beneath the desert sun. As scorers (SteveBrown and myself), our job is to record the numberson the sail of each competitor�s craft as it whizzesby, speeding through the line. One scorer calls outthe number and the other writes it down on a scoresheet that is �hopefully� done in the correct order.Both scorers are ready to jump out of the way of awayward pilot who takes it a little too close to a conefor our comfort while aiming for the official linewhile moving at 60 plus mph.

The Manta Twin truly had a little gitty-up. Earlierin the day on the same playa, I was moving at 22-mph plus or minus 2 to 3 miles per hour in the day�swinds of just 10-mph true wind plus or minus 2-mph. There are not any whitecaps to say the truewind is 13 knots, but the flags are flying straight outindicating 10 mph for the wind. This is a dry lakebedneighbour to the Mojave Desert on which we aresailing, after all. (See Photo and Sketch)

10 CATALYST

Elementarry

I arrived at Coffs Harbour Friday to be met at theairport by Mark Stephens, who took me down to thebeach where the boat was nearly rigged and ready togo. Such service! Donned the wetsuit and off wewent, through small surf and a near on shore breeze.No problem getting going. I took the sheets, Markthe tillers and shunting was very easy. We playedaround a bit and practised shunting, theninadvertently capsized.

The boat lay on its side, but was easily rightedwith help from a passing fisherman (sorry nopictures, Ed.). Top GPS speed 15.6 knots, windaccording to the local yacht club wind gauge, peaked

at 15 knots. The sails looked a lot better, but stillweren�t perfect. The booms bonded to the mastsworked brilliantly, and the new rudder bulkheadsmade the rudders far stiffer and stronger.

Had another sail on Saturday and took family andfriends sailing. Both Bain (Harry builder) andMichele mastered shunting and two tiller steeringvery quickly. Mark and I spent half an hour buzzingupwind and down between two buoys a couple ofhundred metres apart and managed to convinceourselves we were ready to race. Tack shunting wasimproved again, to the point that I reckon we couldgo from hull flying hard on the wind on one tack to

Elementarry - a 7.5 m x 4 m folding sports,daysailing, or camping proa

Reports by Rob Denney & Michele Balharry

Test sail, 7th January 2005, Coffs Harbour, NSWAustralia. S to SE Winds, 10 - 15 knots.

APRIL 2005 11

Denney & Balharry

hull flying hard on the wind on the other tack asquickly as a beach cat. No breakages to fix.

SundaySunday morning headed for Point Manning for

their annual marathon race (no photos of the race).34 kms/18.5 nautical miles of mostly downwindsailing in a narrowish tree linedriver. 50 boats, 12 in our class, twovery hot F18 cats with spinnakersand double trapezes, two nice Acats, a couple of Hobie 18�s, aTaipan 5.6 and a couple of one-offs. Breeze very gusty andchangeable, max was probably 20knots in the puffs. We got therean hour before the start, and wereready to go in 40 minutes. Tyingin the battens takes a large part ofthis, perhaps a reason for having abolt rope mast.

We got a mid-fleet start andblasted off on a broad reach, atsimilar speeds to everyone exceptthe F18�s, one of which was veryquick under spinnaker. The reachbecame a run, and we ended up

on the light air side of the river, very slow. Shuntingto get to the other side was far slower than theothers gybing so we lost ground, although we pickedit back up once we got the breeze. The boat wasmarginally slower directly downwind than the H18�sand A-cats gybing back and forth across the riverwhen we were in the same breeze, much slowerwhen we were on the no wind side. We may havebeen quicker if we had gone wing and wing.Shunting was totally controlled and safe, at least twoof the cats capsized during their gybes.

We had not fitted sheet cleats and Mark (who hadnever raced a boat before) and I are really too old forthis sort of racing so we sat side by side half wayalong the beam, easing the sheets, luffing or bearingaway each time we flew a hull. Fit young fools in anoptimised boat would have been moving in and outwith cleated sheets and sailing much, much quicker.They would also have moved aft on the lee hullduring the shunts to speed them up. They would alsohave lifted the forward rudder as soon as the breezewas aft of the beam, something we only didoccasionally.

The rest of the race was in pretty much the samevein, apart from us going aground to prove the kickup rudders work and a very short stretch hard on thewind when we sailed higher (and much faster) than ahot 14' dinghy which had started an hour before. Wealso had a very quick broad reach, definitely thefastest the boat had yet gone, but the GPS hadturned itself off, so we�ve no idea how quick wewere.

12 CATALYST

Elementarry

We finished 5th; might have been third if wehadn�t run aground. Elapsed time was 93 minutes;the hot F18 did it in 73, a difference of about 25%.Can we find another 25%? With ease! A more activecrew, optimised sails and controls, and better tacticswould easily supply the deficit.

ImprovementsWe then did some thinking and decided that, if

we fitted trapezes, the boat could be a metre or sonarrower, which would make downwind shuntingfaster. This would make it 3m wide. For the loss ofanother 500mm, we could also make it in one piece,saving a lot of weight, cost and complexity. The nextday we tried it untelescoped. Rigging was easier andit felt much easier to sail, according to Mark on thetillers. It was certainly much easier to fly a hull,which we did with gay abandon until we got overconfident and capsized. We were unable to right it;due mainly to water in the pocket luffs, so we tossedout the anchor, removed the sails from the masts(another reason for a track on the masts) and easilyflipped it back up. We were about to start paddling inwhen the police boat came and offered us a tow.Interestingly, with a beam wind, no sails and onlyone rudder down, the boat was moving very nicely atright angles to the breeze, we could have blown/�sailed� ashore.

Further thought led to the idea of a seat outsidethe windward hull. Along with a righting polesystem, these mods will be made in the next fewweeks and we will try again.

The boat is a rocket, very easilysailed and controlled and quick torig/derig. We now need to finetune the controls, try differentwidths and options and learn howto sail it fast.

How did the schooner rigwork? Extremely well, at this stageof the game. Shunting is veryeasy, we can luff the boat head towind until it stops, then pull theforesail to windward, bear awaywith the rudders and go sailing.With the Easyrig, this would notbe possible after about 25 degreesfrom head to wind. The schoonerseems to go upwind well (needsome serious windward work totest this) although how much ofthis is due to the near

rectangularity of the sails, I don�t know. Our sails/rigs looked awful compared to all the other boats, weneed to get the sailmaker involved in the fine tuningof masts, booms and sails asap. Having said this, themasts flex nicely and seem to have very low dragwhen the tops are feathered. Once we decide howwide to make it, we can look at fine-tuning the bendcharacteristics. We are producing a mast in anafternoon now, so this is no big deal.

The steering also works very well, as long as youhold on or sit inboard during any violent coursechanges. This is a good idea as a matter of course, asthe boat accelerates in the slightest puff.

The boat sails nose down when pressed, but thisdoes not affect the handling. The bow shape risesthrough any waves with ease. Can�t wait to try itdownwind in big seas/breeze.

The fishnet trampoline is a pain to rig and keeptight. Lots of options to explore here, but all thathappens is wet feet, so this is not urgent. Thetriangular beams are great, deflecting waterdownwards, although at speed it is still a wet ride.

We did not try the kite, although I think I havenow figured out how it can be flown, after a week�spractise on a leadmine.

Is it a Tornado beater? Not yet, but it certainly hasthe potential to be. Is it fun? Absolutely, with far lessstress on the sailors than Tornado racing.

Rob Denney

APRIL 2005 13

Denney & Balharry

Sandwich maker goes sailing too!

Michele Balharry

Yes, I did eventually get a short sail after variouscombinations of Rob, Mark, Bain and our friendTim, took turns to zoom around the harbour on theElementarry. They were very appreciative of mysandwiches and I was taking photos so I felt contentwatching their obvious joy. The wait was worth everybit of buttered sliced bread.

Mark (captain and husband, in that order) and Ion board, we quickly left the shore. Mark on thesheets near the leeward hull and me sitting at the�rear end� (as in the end furthest from where we wereheaded) of the windward hull holding a tiller in eachhand. Now you will appreciate that I am no sailor.Floating around the river on my self-made Bolgerdesigned sailing dingy doesn�t count for muchalthough it has given me the beginnings ofunderstanding about the wind - water - boatrelationships required by a sailing person. Besides, Ihad full faith in Capt. M.

Two rudders make this boat very manoeuvrable,especially when you don�t know what you�re doing -o.k. when I didn�t know what I was doing - sofollowing clear instruction I held the fore rudderparallel to the hull and steered with the rear rudder.Easy. Whilst the beam obscured my view of the forerudder somewhat it was possible to feel when therudder was parallel and not fighting the water. Alongwe went.

Capt. M. on the sheets wascontrolling the speed we weregoing�hmm, straight towardsthe rock wall and a lot fasterthan my dear dinghy could everdream of going. I�ll admit thatmy faith in Capt. was about towaver as the wall got a lot closerbefore he began to do somethingwith the sheets (I�ll get tounderstand that next time), andsaid �we�re about to shunt, getready to turn the rudders�. I didso immediately, which was toosoon - better to wait until theboat slows down, that way Capt.doesn�t get drenched and fallover on the tramp as the boatvirtually stops dead and therudders make a �noise�.

Next time I was ready. Capt did his thing to thesheets. Boat slowed, I turned the rudders aroundfrom where I was sitting by pushing, then pullingwith the tillers in a circular motion. Capt. didsomething to sails and tightened sheets while I slidsmoothly-ish along the windward hull to the new�rear end� all the while grasping the tillers and stayingon board. That was it - faster than it took you toread this paragraph - shunt complete and off wesped in the other direction. It really was that quickand easy.

Indeed, we sped across the harbour, faster andfaster until up she went, flying a hull. This I was notready for, and being instantly over excited by my newperspective I steered off the wind and down wecame, as in, the boat . . . then me, with a thud andI�m sure I heard a small chuckle from husband.Once I�d collected the tillers and myself, I paid moreattention to what I was doing with the rudders.Making Capt. promise not to sheet in harder I wasable to manoeuvre the boat until the point ofbalance shifted and the hull lightened i.e. lifted, butnot totally out of the water, not just yet. Thatexcitement I will wait for until next time. And I thinkI have to do some sit-ups.

A few more shunts around the harbour and Captand I headed happily to shore. It was someone else�sturn to have some damn good fun.

14 CATALYST

Wave Rocker

Technical DescriptionMost people think about the sea and waves as

something that moves up and down and somethingthat rushes in and out. These observations arecorrect, but there are many other facts about sea andwaves. Two of these are very useful ones; one is thelength or pitch of the waves, the other is the movingmass from the renewable energy passing throughthem. Things that most people do not know muchabout or even consider when it comes to extractingrenewable energy from wave power.

There are a few types of wave energy machines inthe market that use the water rushing in and out of atube to move the air mass in it. This normally drivesa Wells turbine. Others use flotation in various formsusing water on a Wells turbine or pumping serpentsmoving with the waves etc.

When you look at the waves, you may think theyare coming in. They are not coming in as suchthough, it is the effect of the renewable energypassing through the mass of water that in itself isjust moving more or less up and down and back andforth in a circle. What moves the water mass are thetides and sea currents, what you see on the shore isthe same water, moving at the speed of the tide andcurrents with the renewable energy passing throughthe water making the waves. This energy comes fromthe winds caused by the sun.

The accumulated power the wind drag has builtup over the distance it has travelled to get to theshore is released in the breaking waves. That�s whythere are big waves in the Pacific Ocean and shortsteep waves in the Mediterranean and very little oneson an outside boating lake. Distance and wind speeddrag on the surface determine the wave size, theangle of the shore where it comes in gives the finalresult.

The pitch is the distance between the waves,which makes the basic wave pattern. A craft will

change its angle going up the front of anapproaching wave until it gets to the crest. Thenormal angle of the wave face varies between 10ºfrom a wind of 2 m/s and 30º from 10 m/s. That�s agood blow if you are a sailor. It can be steeper nearthe shore just before it breaks.

When the craft is making the effort of going upthe wave face, its weight and the water drag hold itback down the sloping face of the wave. Once thecraft is at the top, which is more or less the neutralposition from all the forces of the wave that wantedto take it with it, being liberated from those forces, itspeeds up as it surfs down the other side. This canbe exhilarating or very frightening in a small sailboatin a big sea, or in a bigger faster boat in an evenbigger sea. Like some folks say when we are veryhappy and enjoying the ride: �They are riding alongon the crest of a wave�.

If we anchored a craft or any floating object, itwould want to go backwards as it fought its way upto the crest of the oncoming energy force in thewave. At the top, it becomes level and its centre ofgravity moves amidships. Going up the wave, thecentre of gravity (being above the waterline) movesaft making it �drag its ass �as they say. Which putsup the resistance on the anchor and tackle. Using anelastomeric mooring system the drag effect can beused to give a better and more useful result.

From the sum of these forces, acting on the hullof the craft, Renewable Energy (RE) can becollected and stored up in an elastomeric mooringsystem. This is like when you use your muscle energyto pull back the rubber on a catapult or a stretchedelastic band to ping across the office.

After the craft has fought this energy that wastrying to push it back (as much as 70 kW per m³average), it then reaches the crest and starts to godown the backside of the wave. The centre ofgravity moves forwards, helping to accelerate thecraft, and with the help of the collected energy

The Wave Rocker

Ken Upton & William Groombridge

APRIL 2005 15

Upton & Groombridge

stored in mooring, the elastomeric effect is released;i.e. �The chain sinks or the nylon rope recovers� innormal moorings. Then the craft starts to movefaster down to the trough of the wave pattern,recovering this collected energy as itspeeds up, onlyto be stopped by the wall of water of the nextoncoming wave.

This effect can be amplified by adding vortex dragfoils or a special shape to the hulls in the lower stern.To increase the drag factor that can help thecollection of this Renewable Energy (RE), a specialtype elastomeric mooring system is used. When thisdrag energy is released, the extra speed has an effecton the craft ~ like a truck slamming into a concretewall or your body on the safety belt when you haveto do a emergency stop. Lots and lots of energy thathas to go somewhere or be absorbed. This RE canbe used in our new revolutionary 4p-wave machineto make a cleaner better world.

For the most beautiful thing about RenewableEnergy is that it does not pollute, spoiling our worldand mankind�s chance of survival. It makes the poorinhabitant of this planet independent of all thepowers that wish to be in control and are destroyingit with the polluting forms of energy that are having

such a devastating effect on our one and only planetand all the life Mother Nature has put on it. Andbeing renewable, it is endless; it will be there andavailable as long as our world turns.

As the old saying goes: �Money is the root of all evil�.Maybe! And perhaps that�s why it�s so difficult to raise moneyto invent, research, develop and build machines in this sectorfor concerned and capable individuals or small organizationslike our charity that work in this field.

How foolish is the greed of the happy few in power! Theirfamilies as well will suffer alongside all of us, because thesepoor little rich people mistake their greed for love andunderstanding for their loved ones and our world. Just thismakes our planet collapse, which it will do soon, if we do notchange our ways. It is already showing major signs of what isto come! Just look at the world news each day if you doubt mywords. In the news headlines every day we see a little of whatis happening, and that is just a fraction of what others seeand know about. Others who are not so lucky to live where wedo, really do have to suffer because of the effects of thisignorance and greed etc etc.

But this article is not about the moral behaviour of ourelite few or the ignorant masses that are brain washed bythem. So, dear reader, let�s go back to the core.

16 CATALYST

Wave Rocker

Now you have to think about a wagon on wheelsconnected to a reciprocating pump. The wagon goesup and down the length of the flat deck of acatamaran boat making the pump work, the pistonrod is connected to the wagon and the cylinder endis connected to the bows.

You should now know all the forces that are goingto be combined to make a clean, cheap, very powerfulRenewable Energy machine. Like you can only make agood meal with common sense and a little bit of love,if you want your loved ones to stay fit and well.

We all know the effect of cargo, something like alarge truck, loose in a ship�s hull, and the damage itcan do, acting like a battering ram topunch a hole inthe ship hull, capsizing it or sinking it. Or the oldsayings of a loose cannon etc. We all know what theslosh effect is, which in addition could be used toamplify the tilt angles of the craft, just as waterballast trim tanks can be added and used to adjustthe sensibility to suit the wave conditions and outputRE wanted.

We also all know what is a child�s rocking horse orgranny�s favourite rocking chair and how they move,but do you really know why? Well, they normallyhave two curved rockers touching the floor. So if wehave the hulls of a catamaran made so that theymake the same effect on the water, there is never atime it stops moving, because the rider or granny orthe waves passing underneath the craft are alwayschanging the centres of gravity & buoyancy. All thefree weight can change its position as well, that�s whyto date, with our simple shoestring R&D, we think aCatamaran type hull the most suitable for this job ��All rock and no roll!�

As the craft (cat) goes upwards on the oncomingwave, the centre of its balance moves towards thestern, making it dig in its backside to resist. This putsa drag force on the hull that is connected to anelastromeric mooring, thus stretching it like it isloading a catapult. Now if there were a weightedwagon on the deck, it would also want to movebackwards down the slope of the deck as the bowcomes up. just like a car rolling backwards on a hill.To stop the wagon going overboard it is connectedto the piston rod of the pump, so with thisbackward movement it sucks in its input charge. (Ora limit stops it for direct linear electrical generationand safety). This working fluid charge helps to startto balance the craft as the cylinder end of the pumpis connected to the bow fills. When the cat gets tothe crest of the wave the charging is finished. It thenstarts to go down the other side of the wave, and the

weighted wagon wants to move to the other endwhere the charge already is, because the centre ofgravity is changing. Just like that car on a hill needsno engine to go down the hill. The wagon starts topush out its working charge as it moves towards thebow. Also something else has to move with all thisrenewable energy that has been collected. The effectof the wagon going forwards levels and speeds upthe cat as it goes down the backside of the wave.Helped by all the other collected energy that is beingdischarged from the elastic mooring system, which isnow getting back to its unstressed position, as thereis no drag load. When the cat reaches the troughbetween of the wave pattern, it then wants to dig inits bows. Because most of the weight is now at thewrong end to go up the coming wave, the digging ofthe bows into the oncoming wave will stop thespeeding cat. The weighted wagon, which is still freeto move in forward direction with the inertia forcesacting on it, move the rod and the piston that ispushing into cylinder, giving the final compressionforce on the rest of the working fluid charge toempty the cylinder. Or make a super charge surge oflinear renewable electrical energy (LREE.)

The renewable energy output then can be used todo many useful things. Like driving a hydraulicmotor connected to a generator to make electricity,pump seawater out of dykes, or make fresh waterfrom the sea through a reverse osmosis systempowered by the waves, while at the same time thisfresh water made on board can all be piped from thecraft to where it�s needed by this real positive powerthe catamaran is floating in. Different pumping andlinear generation systems etc. can be in the hulls andon numerous decks in the craft if required. Thepractical size of the craft would be to suit the seasite, where it was stationed.

In the oceans the distance between wave crest isabout 80 - 100 metres. So a craft of 30-50 m longcould be used with very heavy wagons moving thepumps etc. Being a boat it self-adjusts to the waterlevel and can be moved to where you need it. Thismakes it also ideal for emergency use. Besides, it caneasily be serviced by taking it back to port or out ofthe waves in the lee of a breakwater.

This new renewable energy principle and type ofmachine, which is now working in experimentalforms, when fully developed, will give us all a littlemore hope! Hope for a cleaner and more efficientworld. It is probably the most effective way to usethe positive energy of blowing wind anywhere itmakes a wave.

APRIL 2005 17

Upton & Groombridge

Technical footnote:All foils extracting renewable energy work on the

same dynamic principle. The power ratio comes fromthe density of the fluid flow they are working in andthe angle of attack of the foil to the flow. Forwardfacing wind turbines can never work in the higherangles of attack where they can extract the muchhigher work values. The stresses are too great andbend the blades, plus there are very high shock loadsfrom the pressure difference as the blades pass thesupport tower. These bending moments, huge loadsand stresses cause fatigue that will destroy the blades if

they extracting energy from the best part of thedynamic power scale.

Water has 800 times more density than air Thereforeit has 800 times more potential for renewable energyextraction for the same working size of foil, plus theadded advantage of more constant forces in rivers andtides. Gravity, which is constant, moves rivers, and theexternal forces from the Moon, also constant, makethe tides. The wind blows when it wants to and is alsothe weakest force to use in the power scale of fluiddynamic natural forces for the collection of usableenergy. Water power is much better.

Fill pumpusing gravity

Elastomeric mooringcharged by drag force

Wave direction and RE mass movement

Change over position �pump is full and theelastomeric system fullycharged

Pump out with the changing weight position, and theinertia forces, from the recovery of the elastromericmooring system, are discharged into the RE collectionsystem. The movement of the weight C of G does nothave to balance floatation.

The vortex dragfoil only activateswhen the stern isdown

[Ken Upton and William Groombridge work for 4P, a small ecological charity based at Marina Alta,Alicante, Spain. AYRS understands 4P has patents pending on the priciples of using wave slope andwave-motion-generated inertia to make energy. Potential manufacturers should expect to pay 4P areasonable sum for licensing. After all, they are a charity (and the fee is probably tax-deductable). Ed.]

18 CATALYST

PAS & Mill-Prop principles

For the purposes of this discussion, I shouldmention the following:

1) There are three basic sailing media: gases,liquids, and solid-surfaces (or the equivalent). Thesemay be combined into 18 pairs which represent themedia contexts of sailing: 9 pairs where the �top�medium is moving while the �bottom� medium isstationary, plus 9 pairs vice versa.

2) I define Sailing as: Craft propulsion by extraction ofenergy from the relative motion between two material media(external to the craft) by interacting with both media simultaneously.The material media must have indefinite extension, and themedia flow must be essentially continuous (like the wind)rather than essentially oscillatory (like passing waves).

3) Sailing craft may make use of additional formsof propulsion or locomotion that are not strictlysailing, such as drifting, coasting, gliding, soaring, anddynamic soaring. But only craft that satisfy thedefinition of sailing are sailing craft.

4) There are four fundamental principles ofsailing: Direct Sailing (a sail, kite, or kite-sail producesthrust directly in conjunction with a lateral resistancedevice � or not, as when sailing directly downwind),Mill-Sail Sailing (a mill powers a device that createsthrust like a sail), Mill-Prop Sailing (a mill in contactwith one medium directly powers a prop in contactwith another medium), and PAS (the primary energyconversion devices move aft or slow down when �on�,and move forward especially rapidly when �off �).

5) At present, PAS includes five majorsubdivisions (techniques): Regenerative Sailing(short-term energy storage), Drag Resailing, LiftResailing, Rewindmilling, and Rekiting. (Thesetechniques are more fundamental than, and replace,the �Types� described in my original PAS article.)The prefix �Re� is from �regress�, meaning �to moveaft�.

Wilson�s PremiseMr. Wilson states that my PAS examples �may

seem unconvincing� because they are difficult toanalyze, and he finds them difficult to analyzebecause they use electricity or rubber bands. Mr.Wilson�s statement implies that he was distracted bythe specifics of my examples and missed their point,which was to illustrate basic physical principles forhow to sail either upwind or downwind, or both,faster than the wind, not to engineer specific craft.The specific mechanisms are arbitrary. For example,the twin craft concept illustrates that two sailingcraft, if efficient enough, could work together as ateam to power each other so as to achieve speeds inany direction in excess of what either could achievealone, and faster than the wind on average. Theenergy storage concept illustrates that an efficientenough sailing craft which stores energy can achievespeeds higher than it could achieve otherwise, andpotentially faster than the wind on average.

The Power Alternating Sailing (PAS) Principleand the Mill-Prop Principle;A critique of �Downwind as fast as you like�, plus new examples

Peter Sharp

In his article, �Downwind as fast as you like�, Catalyst 19, Jan. 2005, John C. Wilson offers a principle toexplain sailing down wind faster than the wind (DWFTTW). He begins by stating that no one has offered aunifying principle to explain sailing DWFTTW. His assertion is incorrect. The Power Alternating Sailing (PAS)Principle, which I invented (Catalyst 3, Jan. 2001), and the Mill-Prop Principle, which I discovered (Catalyst 13,July 2003) are sufficient to explain all craft capable, in theory, of sailing directly DWFTTW (and other craft aswell, and other directions as well). I will use them to critique Mr. Wilson�s �new� principle for sailing DWFTTW.

APRIL 2005 19

Sharp

Mr. Wilson�s �New� PrincipleSince Mr. Wilson considers my PAS examples to

be �unconvincing�, he proposes a �new� principle toexplain sailing DWFTTW. He illustrates his �new�principle in his Fig. 6. Astonishingly, his �new�principle is my PAS Drag Resailing technique that Ipresented five years ago in my original PAS article.See my drawing �Type 3 PAS: Downwind ToyVehicle�. My drawing shows two drag sails thatalternately oscillate fore and aft, to oscillateconnecting rods that crank two large wheels fixed tothe same axle. The propulsive drag (thrust) of thedrag sails pushes the wheels, and the wheels in turnprovide the power to oscillate the sails. As a result,the sails move aft relative to the large wheels whenthe sails are �on�, and forward faster than the largewheels when �off �. Since the large wheels have alarger radius than the crank pins� radius, the largewheels force the �on� sails against the wind.

Mr. Wilson�s Fig. 6, his key drawing, which isintended to illustrate his �new� principle, is merely aschematic version of my drawing. Same concept. MyPAS Drag Resailing technique may be implementedusing other mechanisms as well.

My drawing �Mechanical Analogue of BauerVehicle� in my PAS article, and my drawing �Mill-Prop Craft (Solid Surface / Solid Surface)� in myMill-Prop article, which are essentially the samedrawing, both illustrate how a ruler can be used topropel a vehicle with different diameter wheels fasterthan the ruler, as shown in Wilson�s Fig. 6. Thedifference is that the rulers in my drawings aretreated as the moving, propulsive medium � ratherthan as a crank mechanism as in my downwind toyvehicle � so the vehicles are Mill-Prop craft ratherthan PAS Drag Resailing craft. The addition of dragsails, and means to oscillate them, converts a (solid-surface/solid-surface) Mill-Prop craft into PAS DragResailing craft. It is important to note that PAS

designs often use complete or partial Mill-Prop craftas sub-units.

Mr. Wilson states his �new� principle as follows:To sail DWFTTW: �...part or all of the propulsionmechanism must be going less than the speed of thewind, at least part of the time. Of course, it mustnot always be the same part, or else not all the time:otherwise that part will get left behind. Therefore,the mechanism has to be oscillatory in some way.�

First of all, that is not true for Bauer craft, whichcan sail DWFTTW with no parts moving slowerthan the speed of the wind. So his �new� principlefails as a universal explanation of sailing DWFTTW.

Second, my Power Alternating Sailing (PAS)Principle, by definition, implies that the mechanismsmust be oscillatory in some way.

Third, his statement of his �new� principle istechnically incorrect even for PAS. For example, itwould not apply to a land yacht broad reaching at aVmg downwind greater than the wind speed, whilestoring energy, and then turning directly downwindto use its stored energy to further increase its Vmgto many times the wind speed. The vehicle could useone of its wheels to generate and store the energy inone of various ways. No part of the vehicle needmove at less than the speed of the wind, at any time,while broad reaching or while sailing directlyDWFTTW. So his �new� principle fails again.

The PAS PrincipleTo state the PAS Principle, it helps to use of a

concept called �the average location� of the craft asa whole. The average location is, under steady stateconditions, equivalent to an imaginary point movingat the average speed of the craft as a whole.Therefore: PAS craft make use of one, two or moreprimary energy conversion devices (such as dragsails, lift sails, kites, kite-sails, or windmills) whichoscillate fore and aft relative to the average locationof the craft ( such devices move aft when �on�, and

Wilson�s Fig. 6 Inchworm: end of pushing phase.

20 CATALYST

PAS & Mill-Prop principles

ahead when �off �); or, when storing energy, the craftas a whole moves aft relative to where it wouldotherwise be (it slows down). That statement appliesto all of the five PAS techniques, and it is not inconflict with the Mill-Prop Principle.

PAS craft also make use of lateral resistancedevices. When advancing against or with the movingmedium, some require additional resistance devicesin the stationary medium to stabilize the �on�primary energy conversion devices in the movingmedium.

The reason for oscillating the primary energyconversion devices is to maximize their power orthrust when �on�, to minimize their retarding dragwhen �on�, and to minimize their retarding dragwhen �off � and advancing especially rapidly. Theadvantage of PAS is its potential for higher speedsand/or higher average speeds. The disadvantages ofPAS are the complexity and inertia of the energyconversion devices. In general, although not in allcases, the four fundamental principles of sailing (inthe order listed above) are characterized byincreasing degrees of complexity and versatility.

A comment on the PAS Regenerative Sailing(short term energy storage) technique is in order.The stored energy can be used to head directlyupwind, or downwind, faster than otherwise. Whenreaching under varying wind conditions, the storedenergy can be stored during strong winds andexpended during weak winds so as to increase theaverage speed of the craft. The stored energy canalso be used operate onboard devices.

Wilson�s Fig. 1It is important to note that Mr. Wilson�s Fig. 1 (a

spool of thread moving faster than the thread thatpulls it) shows a partial Mill-Prop craft (not a

complete Mill-Prop craft). The thread can wind uponly so far onto the spool, thus limiting the distancethe spool can travel. That is why the spool is only apartial Mill-Prop craft and not a true sailing craft.(Many PAS craft would incorporate partial orcomplete Mill-Prop craft as sub-units.)

I believe the first example of a partial Mill-Propcraft propelled by wind was Theo Schmidt�s modelboat that was pulled DWFTTW for a limited distanceby a kite (AYRS 100). It should be possible for kitebuggies to briefly accelerate to very high speeds byusing an onboard spool, powered by one of thewheels, to wind in the kite lines very rapidly. Such akite buggy would be a Direct Sailing craft combinedwith a partial Mill-Prop craft.

Unfortunately, Mr. Wilson abandons the spool ofthread concept instead of modifying it to make it acomplete Mill-Prop craft. To make it a complete(true) Mill-Prop craft, it must be able to travel anindefinite distance, without an inherent theoreticallimit. That could be easily achieved. For example, justloop a continuous string once around the spool sothat the string crosses itself at the bottom of thespool. Then tie a small weight to the trailing end ofthe string, thus giving the string traction around thespool when the string is pulled taught. Finally, extendthe string an indefinite length ahead of the spool.The spool could then travel an indefinite distance,and it would be a complete Mill-Prop craft, a truesailing craft. It would then be able to sailcontinuously �down string faster than the string�.

Note carefully that the spool takes its energy fromthe string but takes its power from the ground. Thatinsightful distinction was made by Victor Korepanovwhen discussing Bauer vehicles (�Four Times Fasterthan The Wind�, Catalyst 18, Oct. 2004). Thedistinction applies to all Mill-Prop craft where themill-medium is regarded as the stationary medium. (Itwould not apply to a Bauer vehicle on a conveyorbelt since the moving belt is the source of bothenergy and power.) Note that the improved spoolwould be a true model sailing craft in its own right,not just an analogy. That is because sailing is possiblewithout wind or even air. The fundamental principlesremain the same even when applied to a craft thatextracts energy from the relative motion of twosolid-surfaces (a string may function as the equivalentof a solid-surface).

APRIL 2005 21

Sharp

The speed of the improved spool would probablybe less than 4 times the speed of the string due tofriction, no matter what gear ratio were used (therelative lengths Wilson�s �R� and �r�). This estimateis based on Theo Schmidt�s results for a Mill-Propcraft sandwiched between two planes (AYRS 100). Ittoo used a wheel-mill to rotate a wheel-prop, and itsdesign was quite efficient. As �mills� and �props�,wheels can be more efficient than turbines andpropellers, and propellers are usually much moreefficient than turbines.

The Mill-Prop PrincipleMills include windmills (gas turbines), water-mills

(liquid turbines), and wheel-mills (a wheel, or anequivalent device such as a passively oscillating [sideto side] skate-mill, whose drag is used to generatepower). Wheel-mills work on solid-surfaces or theequivalent, such as ground, ice, or strings. Propsinclude gas (air) propellers, liquid (water) propellers,and wheel-props (driven wheels or equivalent devicessuch as active skate-props). By definition, millsalways interact with the mill-medium, and propsalways interact with the prop-medium.

A Bauer vehicle uses a wheel-mill and an air-prop,so its mill-medium is the ground and its propmedium is the air (blowing or not). A windmillvehicle uses a windmill and a wheel-prop, so its mill-medium is the air (blowing or not) and itsprop-medium is the ground. Both a model windmillvehicle and a model Bauer vehicle could functionnormally if placed on a moving conveyor belt in awindless room. The Bauer vehicle could moveagainst the direction of the belt faster than the belt(and has actually done so). The windmill vehiclecould easily outrun the belt (by using the relativewind). A Bauer vehicle outdoors takes its power fromthe �relative moving ground� � but its energy from

the wind � just as a windmill vehicle on a conveyorbelt would take its power from the relative moving air(wind) � but its energy from the belt.

If we ignore the manner in which they aresupported against gravity, and ignore whether or notthey make use of a lateral resistance device, all Mill-Prop craft work alike. They are all, in principle, thesame abstract craft. The mill (in or on one medium)directly powers the prop (in or on the other medium)� regardless of which medium is actually moving�and the craft can sail directly against its mill-medium.When sailing against its mill-medium, the mill-medium is usually the faster medium relative to thecraft. Mill-Prop craft, like other sailing craft, are�blind�. They sense only the relative motion betweentheir two material media used for sailing. Theycannot �tell� which medium is actually moving. Theydo not �care�.

In my drawing, �Equivalent Mill-Prop Craft�, Ishow two images of the same combined spool � asmall spool (P, the prop) fixed to a large spool (M,the mill). The mill (M) always rotates the prop (P).The combined spool rides on two strings. In the topsketch, the spool combination moves to the rightfaster than the top string while the bottom string isstationary. In the bottom sketch, the spoolcombination moves to the left against the directionof the bottom string while the top string isstationary. With minor modifications, it is possible toconstruct a working model of such a sailing vehicle.

The string in contact with M is the mill-medium.The string in contact with P is the prop-medium.This combined spool is a complete Mill-Prop sailingcraft in its own right. It is also analogous to a Bauervehicle and to a windmill vehicle, respectively,outdoors in the wind. It shows that Bauer vehiclesand windmill vehicles are, in principle, the sameabstract craft. In both cases, the mill in one medium,rotates the prop in another medium. It is only whenthe abstract craft (the Platonic ideal) must exist in thereal world that it must take on specific forms for itsmill and its prop � such as a windmill to interactwith wind, and a wheel-prop to interact with theground or a string.

To understand the difference between a Mill-Propcraft and a PAS Drag Resailing craft, compare mydrawing with Wilson�s Fig. 6 (my Drag Resailingtechnique). Note that in a windless room, the spoolshown in his Fig. 6 could advance against the

Wilson�s Fig. 1. Spool-of-thread analogy

22 CATALYST

PAS & Mill-Prop principles

direction of a moving conveyor belt faster than thebelt � if the craft were efficient enough. In thatcase, the belt would be the moving medium, and thesails would function only as a crude propeller sincethere would be no wind. It would work like a Bauervehicle except for the additional oscillations.

Even in a true wind it is possible to combine awindmill craft and a Bauer craft into the exact samecraft so as to illustrate that they must be based on thesame principle. See my drawing �Windmill/BauerBlimp�. The craft consists of a blimp with apropeller at the bow (but with no tail fins since theywould turn the blimp into the wind), and a verticalaxis wind turbine (VAWT) suspended far below (100meters), near the ground (or water). The VAWT issuspended by a very long and light torque tube that isconnected to the propeller shaft using a type ofuniversal joint that permits the torque tube to swingfore and aft from the transmission without pitchingthe blimp. The VAWT powers the air propeller. Sincethe blimp is powered by a windmill, it is a windmillcraft. Since the blimp uses a propeller to outrun thewind, it is a Bauer air propeller craft.

Due to the wind gradient, the drifting blimpwould pull the VAWT along faster than the wind nearthe ground (or water). So the VAWT wouldexperience a relative wind from ahead. The VAWTcould convert that relative wind into power to rotatethe blimp�s propeller. That would enable the blimp tosail a little faster directly downwind than the truewind around the blimp. Since this craft is,simultaneously, both a windmill craft and a Bauer airpropeller craft, it demonstrates that both types ofcraft must be based on the same fundamentalprinciple of sailing, the Mill-Prop Principle. Note

that if the true wind is used as the frame ofreference, the blimp may be seen to be sailing directlyupwind rather like a (upside down) windmill boat.

The Mill-Prop Principle may be stated as follows:�A Mill-Prop craft is powered by a mill interactingwith one material medium to directly power a propinteracting with another material medium.� It doesnot matter which medium is the moving medium aslong as the movement is in the correct direction.When moving laterally relative to the mill medium,the craft will usually require an additional lateralresistance device in the prop medium.

Since all Mill-Prop craft are based on the sameprinciple, it should be possible to formulate a single,generalized, mathematical statement to describe allMill-Prop craft, based on their mills and props ingeneral (not on their specific mills and props, such aswindmills or water propellers), and on their mill-medium and their prop-medium in general (not ontheir specific media, such as wind or ground).

Jon Howes has mathematically described a Bauervehicle on a conveyor belt (Catalyst 12, April 2003).The special advantage of his description is that itfocuses on the wheel-mill as providing power andmakes no reference to wind. It should therefore bepossible to generalize the definitions of his terms sothat his mathematical statement will describe anyMill-Prop craft sailing directly against its mill-medium(not just the Bauer vehicle). His generalized termswould then be defined as follows: Vw = speed of themill-medium; v = increment by which the mill-medium is exceeded; F = drag on the mill; T = thrustof the prop; n = efficiency of the drive train andprop; and P = power in or out of the system. So, wenow have a verbal and a mathematical statement ofthe Mill-Prop Principle.

APRIL 2005 23

Sharp

Wilson�s Figs. 6 and 7As mentioned, Mr. Wilson�s Fig. 6 is equivalent to

my drawing of the �Downwind Toy Vehicle� in myPAS article. Therefore, Mr. Wilson�s Fig. 6 may bedescribed as an abstract approximation of one of themany versions of the PAS Drag Resailing technique� wherein two or more drag sails oscillate fore andaft by using the propulsive drag of the �on� sail bothto propel the body of the craft and to advance the�off � sail faster than the body of the craft. Then thecycle reverses and repeats.

My drawing of the �Drag Resail Land Yacht� isfrom my 2003 entry for the Hogg Prize. (My 100page entry was too long to publish, but copies weremade available to AYRS members by our editor,Simon Fishwick. My book will update and expandthat material and make it more widely available.) Mydrawing is merely an improved version of my�Downwind Toy Vehicle�. Two circulating belts aremounted on pulley wheels fixed to the groundwheels and to the axle, outboard of the wheels. (Thepulley wheels have a smaller radius than the groundwheels so that the ground wheels can force the pulleywheels to rotate.) The belts serve to increase thestroke length and cycle time of two oscillating dragsails so as to increase the efficiency and speed of thevehicle.

This vehicle is counterintuitive. Note that the pushrod of the �on� sail would push against the bottomof the belt which is moving aft relative to the craft.And the �off � drag sail would be pulled forward bythe top of the belt. To understand this vehicle, ithelps to focus on the �on� drag sail and to regard therest of the vehicle as a step-up transmission topropel the body of the vehicle (and the �off � dragsail) faster than the �on� drag sail.

Drag Resailing BoatsFor PAS Drag Resailing boats, a similar mechanism

using a paddle wheel instead of ground wheels wouldwork, although a simpler alternative is shown in mydrawing �Drag Resail Catamaran with Double EndedPaddle�. The paddle is like a kayak paddle where oneblade or the other dips into the water while the paddleshaft oscillates. The paddle blade in the water serves asa fulcrum (and temporary sea anchor). The �on� (open)drag sail next to it serves as the point of effort. And theboat serves as the point of resistance. When theadvancing �off � drag sail exceeds the speed of the

wind, it folds back into an aerodynamic shape tominimize its aerodynamic drag.

If the �on� drag sail is half way between thepaddle in the water and the boat, the boat must movedownwind at about twice the speed of the �on� dragsail. If the sail moves downwind at more than halfof the speed of the wind, the boat will sailDWFTTW. Mounting the sails closer to their paddleswill decrease the true speed of the �on� sail, willincrease the propulsive drag of the �on� sail, and willincrease the speed of the boat � until the retardingdrag forces equal the thrust of the �on� drag sails. Itis important to note that the paddle in the water doesnot create a retarding hydrodynamic drag to slow theboat. Nor does it function as a paddle to propel theboat. It serves only as a temporary sea anchor andfulcrum. (I have invented additional ways to reducethe hydrodynamic drag of both PAS boats and Mill-Prop boats so as to enable them to sail DWFTTW.)Conceptually, the double ended paddle may also beregarded as an oscillating, passive �paddle wheel�.

Rewindmilling BoatsThe same sort of oscillating double ended paddle

could be used to oscillate two VAWT. A blade (notshown in the drawing) would be lowered into thewater below the �on� VAWT to serve as a temporarysea anchor. The blade would be perpendicular to thedirection of travel of the boat. The boat would alsouse a conventional lateral resistance device. The �on�VAWT would propel the boat by means of a drivebelt to the boat�s propeller shaft. At the end of its�stroke�, the �on� VAWT would be turned �off �(feathered) to reduce its drag, and the oppositeVAWT would be turned �on�.

When reaching, the VAWT blades could beconverted into wingsails to increase the speed of thecraft. Since the VAWT provide power, the craft couldbe a hovercraft with a centerboard and rudder. Inprinciple, this Rewindmilling craft would be capableof sailing in any direction faster than the wind.

Wilson�s Concluding RemarksIn his concluding remarks, Mr. Wilson gives

examples of craft he believes would be similar inprinciple to his Fig. 6 (my PAS Drag Resailingtechnique). The first is a land/ice yacht that sailsdownwind on a broad reach and then turns to coast

24 CATALYST

PAS & Mill-Prop principles

directly downwind. It would briefly exceed the speedof the wind while slowing down. Mr. Wilsonsuggests it is related to his Fig. 6. It is not. It ismerely an ice yacht coasting directly downwind.

All sailing craft coast at some time, so coastingdoes not define their principle of operation. It is truethat the acceleration of the ice yacht stores kineticenergy in the mass of the ice yacht, and that theenergy is dissipated during coasting. But that is truefor all sailing craft, so it is not definitive. It is not, forexample, equivalent to PAS Regenerative Sailing(short term energy storage) wherein a land yacht,after using one of its wheels to generate and storeenergy in an energy accumulator while broadreaching, could turn directly downwind and thenaccelerate (rather than coast).

Also in his concluding remarks, Mr. Wilsonproposes the use of a vertical axis wind turbine(VAWT) to sail DWFTTW since the blades on theside moving against the wind could be movingdownwind slower than the wind, even if the VAWTas a whole were moving DWFTTW. That would notwork. The VAWT would simply run out of wind as itapproached the speed of the wind. What would workis a vertical axis propeller. But then the craft wouldbe a Bauer craft, which uses the Mill-Prop Principle,not the PAS Principle (Drag Resailing) as in Mr.Wilson�s Fig. 6.

Mr. Wilson also suggests that a paddle wheelturbine on its side with its shaft perpendicular to thewind would work. It would not. As before, it wouldrun out of wind. However, it would be possible tomodify a special kind of paddle wheel to sailDWFTTW. It would be rotated by one of the wheelsof the vehicle. The vehicle would be another kind ofPAS Drag Resailing craft.

Note that if efficient enough, this or other PASDrag Resailing land yachts, if placed on a movingconveyor belt in a windless room, would be able toadvance against the direction of the belt faster thanthe belt, like a Bauer vehicle. The sails wouldfunction as a crude propeller. If the sails were largeenough and light enough, they could be efficient.Note that Mill-Prop craft would use paddle wheels asunits � as mills or props. But PAS craft could usepaddle wheels as a collection of oscillating bladesthat turn �on� and �off �. For example, a DragResailing boat could use a conventional paddle wheelin the water as a mill to rotate a modified Janko�paddle wheel with sails in the wind. A Mill-Prop boatcould use a conventional paddle wheel as a mill in thewater to rotate a conventional air propeller. The keydifference between PAS Drag Resailing craft andMill-Prop craft is that Drag Resailing craft employsome form of �on� and �off � oscillations, whereasMill-Prop craft do not.

It is important to recognize that the drag sails of aPAS Drag Resailing craft can function simultaneouslyas sails, a windmill, and a propeller � dependingupon the perspective of the analysis. They functionto produce power like a windmill, and thrust like apropeller.

Mr. Wilson concludes by strongly insisting that a�Bauer vehicle� does not use the same principle asshown in his Fig. 6, and he believes that some otherprinciple must be involved. That conclusion iscorrect, but quite obvious. The Bauer vehicle is basedon the Mill-Prop Principle, which I have explained ingreat detail. His Fig. 6 is merely a schematicillustration of one of the many possible ways toimplement my PAS Drag Resailing technique.

APRIL 2005 25

Sharp

Regenerative Sailing (short term energystorage)

Since we have two new fundamental principles ofsailing to work with, we can use them to evaluate newtypes of sailing craft. I will briefly mention twoexamples of new, real-life, sailing craft based on thePAS Principle and the Mill-Prop Principle.

A company called HaveBlue has integratedcomponents from various high technologymanufacturers to create two ocean cruising yachts, amonohull and a catamaran, that use a concept theycall �Regenerative Sailing�. Regenerative Sailing isequivalent to my original PAS Short-Term-Energy-Storage, so I have adopted their term.

Regenerative Sailing eliminates the need for aconventional diesel engine and greatly reduces theamount of diesel fuel carried on board for the back-up generator. The boat�s propeller(s) is driven by anelectric motor(s) that can function as both a motorand a generator. The propeller functions as both apropeller and a water turbine. During strong winds,the propeller is used as a water turbine to generateelectricity, which is then stored on board. Generatingelectricity reduces the hull speed by about 1.5 knots.During light winds, or no wind, the stored energy isused to propel the boat � at up to 8 knots.Consequently, the average speed of the boat duringthe voyage can be increased by 0.5 to 1.0 knots,although that depends upon many variables.

The water turbine is capable of providing all ofthe electricity for lighting, air conditioning,electronics, cooking, water desalinization, and hotshowers. Since the energy storage devices are chargedand drained in short cycles during the voyage, theyfunction as energy accumulators; they smooth outthe flow of available energy. I would say that they�distribute� the available energy over time.

The electric motors are run constantly so that theyspin the prop just enough to eliminate its drag. Whenclimbing a wave, the motor/generators help topropel the boat. When gliding down a wave, themotor/generators feed electricity back into theenergy accumulator. The result is noticeablysmoother sailing.

Regenerative Sailing boats are no longer limited bythe amount of fuel they can carry. One of the crewsbelieves that all energy could have been derived fromthe wind during the voyage. If it is, the sailboatremains a pure sailboat, a PAS boat.

Anders Ansar�s �Stripkite�My second example is actually a prediction based

on my Mill-Prop Principle. A long (about 20 meterslong, as best I can determine) strip kite has been usedto sail directly upwind and directly DWFTTW on ice.The kite is extremely simple. Anders Ansar, the Ice-Wing innovator, developed it. I call his kite, for lackof a better name as yet, an �Ansar stripkite�. It is avery long strip of flat plastic material with somestiffness, and with a stiffening rod located at eachend, like a batten, that serves as a handle with whichto change the pitch of the stripkite. Two ice skatershold the opposite ends.

For sailing directly upwind, the skaters face intothe wind with the stripkite between them, and pitchthe stripkite up by twisting the ends. It rises to forman arc. In the process, it pulls the skaters toward eachother. The skaters angle their skates so that for eachmeter they move toward each other, they must move5 meters forward � until the stripkite peaks in anarc. Then the skaters pitch the stripkite down so thatit descends and becomes straight between themagain. At the same time, they coast away from eachother to take up the slack. By repeating this twostroke cycle, they can sail directly upwind. The kite,when arched, is 30 degrees from vertical, indicatingthat it has a lift to drag ratio of 2. Mr. Ansar gives noupwind speed ratios.

Sailing DWFTTW is more astonishing. Theskaters skate directly downwind until they exceed thespeed of the wind. Then they begin repeating thecycles as before, and they continue to sail DWFTTW.Mr. Ansar suggests that the stripkite uses the relativewind from ahead to propel the skaters.

However, a different explanation is needed toexplain the stripkite�s downwind performance sincethe existing explanation could lead to perpetualmotion machines, which are not possible. In otherwords, the current explanation implies that, underwindless conditions, the skaters could skate forwardto create a relative wind and then use that relativewind to propel themselves. That would not bepossible since there would be no source of energy(other than the skaters themselves). Sailing requires arelative motion between two material media, such aswind and ice.

I explain the combination of the stripkite andskaters as based on the Mill-Prop Principle.

26 CATALYST

PAS & Mill-Prop principles

Specifically, when moving directly upwind, I suggestthat they function as a pulsed-power-windmill iceyacht with a coasting recovery stroke. The powerstroke is the stripkite�s upstroke. I predict that thespeed directly upwind will be no more that 0.5 timesthe speed of wind because the stripkite is functioningas a windmill, and windmill craft typically cannotexceed about 0.5 times the speed of the wind whenheading directly upwind.

When they are sailing DWFTTW, I predict thatthey function as a pulsed-power-Bauer-air-propellerice yacht with a coasting recovery stroke. Now thepower stroke is, I predict, the stripkite�s downstroke� even though that is not what Mr. Ansar reports.

In other words, when sailing DWFTTW, thestripkite becomes a flapping wing propeller (like abird wing) during its downstroke, and the power toflap it comes from the ice as the skaters angle theirskates in order to move apart � even though theirpropulsive energy is ultimately derived from thewind. They work like a Bauer air propeller vehiclewhere the propeller is powered by a wheel, and theground is the source of power, even though theenergy comes from the wind.

Since we now have an example of a kite that cansail directly upwind as a Mill-Prop windmill craft, letus consider how to construct a PAS Rekite boat thatcould sail directly upwind faster than the wind, atleast in principle.

The boat would use two or more kites thatalternately pulled their kite lines downwind. The�on� kite would pull downwind to propel the boatand the �off � kite upwind. The �off � kite would beplaced in a low-drag configuration so as to minimizethe power consumed when pulling it rapidly upwindin preparation for its next power stroke. The pitchangle of the kites would need to be remotelycontrolled, perhaps by radio control. The �on� kiteline would spin the boat�s propeller via a drum and atransmission. A matching drum (below the drum inthe drawing) would haul in the lines of the �off �kite. A paddle blade in the water would serve as atemporary sea anchor to resist the downwind pull ofthe �on� kite, while the other blade was lifted out ofthe water and advanced to its new position inpreparation for the next power stroke. The boatitself would not be retarded by the high downwinddrag of the �on� kite.

I hope my comments have helped to clarify thePAS Principle and the Mill-Prop Principle, and todemonstrate that they can explain all craft capable, intheory, of sailing DWFTTW.

Peter A. Sharp2786 Bellaire Place

Oakland, CA 94601sharpencil@sbcglobal.net

4 February 2005

APRIL 2005 27

Notes from Toad Hill

So now we might talk a bit again about Down Wind Faster Than The Wind. There has beena plethora of abstruse articles on this, but now it is time, I suggest, that we get on with thisproject and, using a term with pejorative connotations, form a COMMITTEE! The Committeecould be formed of some or all of those individuals who have written articles about this subjectsince the inception of the Catalyst. The duty of the committee would be two-fold:

1. To outline strictly the test procedures that any DWWFTW machine would have to pass.

2. To sort out all of the developed theoretical data and come up with an actual rough DESIGNthat could be turned into a mechanical drawing so that a full sized vehicle could be built.

It appears the vehicle could perhaps best be a wheeled vehicle that could be tested on dry flatland. It would be as small and as light as possible for easy transportation to and from any test siteand for ease of construction. As was previously suggested by an interested individual, dry landis the choice test site so as to keep �hull/water� friction out of the equation. Better yet, anabandoned narrow gage railway would be better but wind direction is of course a problem here.I envision something on three bicycle wheels but from then on we need the input from thecommittee. Further, if we should possibly even get this far, I would volunteer my services toactually DRAW UP a mechanical drawing since I have a straight edge, and compass and dividersand with the blessing of Euclid, I could even add a few more drawing aids, perhaps adding aplanimeter, an item to measure degrees, and a graduated scale even though the dividers wouldsuffice here, and maybe even an erasure. The humble design engineer would be grateful to theCommittee for rough sketches of any complex design ideas such as variable pitch windmills, etc.

Hopefully, the drawings would be reviewed by the Committee; and adjustments made ifnecessary so that a final approved set of drawings could result. At that time, we could then startto think about actually constructing the vehicle.

I further SUGGEST that a list of the components be developed and that the Committee farmout parts of the machine to those volunteer individuals who have expertise in fabricating someof the components. For instance, I have at the Toad Hill Boat Shop a lathe (not made in China)with an eleven-inch swing that could be used for turning bearing housings, etc. I also have ahalfway decent wood shop that is capable of turning out 17 foot boats (not considering energyinput). I envision we members fabricating these parts and sending them to some location in theUK or the western desert of the U.S. for final assembly. Once assembled then, of course, themachine could be turned over to the testing Committee. And this is when the real fun starts!What say ye all? Should we all not get busy? Please hurry as I am running out of steam.

Congratulations on the A.Y.R.S.�s 50th.Frank Bailey

A Suggestion, and an OfferSomewhere between 1832 and 1898 a mathematician said the following:

�The time has come,� the Walrus said�To talk of many things:

Of shoes � and ships-�.�

28 CATALYST

Catalyst Calendar

This is a free listing of events organisedby AYRS and others. Please send detailsof events for possible inclusion by postto Catalyst, BCM AYRS, LondonWC1N 3XX, UK, or email toCatalyst@ayrs.org

April6th AYRS London meeting

Subject to be confirmed. 19.30for 20.00hrs at the LondonCorinthian Sailing Club, UpperMall, London W6. Contact:AYRS Office, BCM AYRS,London WC1N 3XX; tel: +44(1727) 862 268; email:office@ayrs.org

24th Beaulieu Boat JumbleAYRS will be there on StandR320/9.

24th BMMA MeetingYeovil: Start times will be 10.30.Sailing is free to BMMAmembers. Non-members areoffered the choice of joining theassociation or paying a £5 sailingfee. Visitors are welcome butplease contact Robbie Nevitt on01963 370058 prior to the eventas some venues have restrictedaccess. Directions to the venuesare available from Robbie andmost are available via the MYAwebsite (www.mya-uk.org.uk)Further information about theBMMA is available by contactingRobbie.

May16th-20th AYRS sailing

meetingPortland Harbour, Dorset, UK.(Neap tide, going to Springs).Shore location to be confirmed.Contact Bob Downhill, tel: +44(1323) 644 879 email:icaruswr@tiscali.co.uk

21st BMMA MeetingPortishead: See above. Contact:Mike Dunkley on 01252 721439for details

June5th AYRS Trophy Race

Worthing SC, UK. Open to allkinds of boats, fastest round thecourse wins. Contact: CharlesMagnan, email:crmagnan@yahoo.co.uk

12th BMMA MeetingGuildford: See above. Contact:Mike Dunkley on 01252 721439for details

July2nd BMMA Meeting

Cotswold: See above. Contact:Mike Dunkley on 01252 721439for details

August13th BMMA Meeting

Woodley: See above. Contact:Mike Dunkley on 01252 721439for details

October8th-14th Weymouth Speedweek

Portland Sailing Academy,Portland Harbour, Dorset UK.Contact: Bob Downhill; tel: +44(1323) 644 879 email:icaruswr@tiscali.co.uk

12th AYRS Weymouth meetingSpeedsailing. 19.30 for 20.00hrsat the Royal Dorset Yacht Club,Upper Mall, Weymouth. Contact:AYRS Office, BCM AYRS,London WC1N 3XX; tel: +44(1727) 862 268; email:office@ayrs.org

22nd BMMA MeetingGosport: See above. Contact:Mike Dunkley on 01252 721439for details

November2nd AYRS London meeting

Subject to be confirmed. 19.30for 20.00hrs at the LondonCorinthian Sailing Club, UpperMall, London W6. Contact:AYRS Office, BCM AYRS,London WC1N 3XX; tel: +44(1727) 862 268; email:office@ayrs.org

December7th AYRS London meeting

Subject to be confirmed. 19.30for 20.00hrs at the LondonCorinthian Sailing Club, UpperMall, London W6. Contact:AYRS Office, BCM AYRS,London WC1N 3XX; tel: +44(1727) 862 268; email:office@ayrs.org

AYRS John Hogg Memorial Prize Award 2005The AYRS announces another award of a £1000 Prize in memory of John Hogg, the

distinguished amateur yachting researcher, who died in 2000.

The aim of this international award is to encourage and recognise important amateur contributionsto the understanding and development of sailing performance, safety and endurance. Preference willbe given to on-going work where the prize money is likely to benefit further development. Other thannominations for a �lifetime achievement� award, the work should have been performed within thelast few years. Work that has previously been entered for the John Hogg Prize is not eligible, unless inthe intervening period significant advances have been made.

Nominations, whether of oneself or another, should be submitted to the Honorary Secretary,Amateur Yacht Research Society, BCM AYRS, London WC1N 3XX, UK, to arrive by 1st October 2005.Nominations may be made by or for anyone, whether or not they are a member of AYRS. Thosenominating someone else must obtain the written agreement of the nominee .

�Amateur� in this context means primarily work done as a pastime and largely self-funded. Details should begiven of any grants or other funding or assistance received. Work carried out as part of normal employment isnot eligible, neither is paid-for research where the researcher does not own the results, but subsequentcommercial exploitation of research need not debar work carried out originally as a pastime.

Whilst it is not essential that any innovations embodied in the work be demonstrated and �debugged�, thework must have some practical application, which should be made clear in the entry.

The submission shall cover the following:-• A summary, of not more than one page, identifying the nominee and the work submitted, and including

a short statement of its merits to justify its submission.• The description of the work itself, its novelty, its practical application, its degree of success to date, and

(briefly) your hopes for the future.• Submissions must be made in English, in hard copy, to arrive by the due date. FOUR COPIES ARE

REQUIRED � one for each of the three judges and one for the Secretary.• Diagrams, graphs and photographs may be used, video material on VHS PAL videotapes or DVDs can

be helpful supporting material. Programs and presentations on disk may be entered as part of a submission.Appendices may be used, e.g. for mathematical workings.

• Entries should be printed on A4/letter paper in a legible font.• Separately, a brief biography of the nominee(s) should be included, and their amateur status and

qualifications should be explained.• Nominees may care to say how they will use the prize should they win.• AYRS will wish to publish brief summary accounts of entries, and may also seek further articles from

entrants. Grant of permission to publish such articles is a condition of entry. To this end it will be helpful if entriescan (if necessary) readily be abridged for publication in Catalyst, and if a computer disk copy of the entry is included.However any information received as part of a submission will be treated �In Confidence� if so marked.

The winner and runners-up will be announced at the London Boat Show in January 2006. All short-listedentrants will receive one year�s free membership of AYRS and a certificate; the winner will receive a cheque for£1000. The Judges, whose decision shall be final, will co-opt experts as required to assist their deliberations.

Submission of an entry will be taken as signifying the entrant�s acceptance of these rules.

Queries concerning possible entries may be made by phone or e-mail to the AYRS HonorarySecretary on tel/fax +44 (1727) 862 268; e-mail office@ayrs.org.

Catalyst �a person or thing acting as a stimulusin bringing about or hastening a result

On the Horizon . . .

Amateur Yacht Research SocietyBCM AYRS, London WC1N 3XX, UK

Printed by HenDi Systems Ltd, London N1 6DL.

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