Photo Essay: How to Build a Seneca - Spira Internation ?· Photo Essay: How to Build a Seneca Plans…

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<p>Photo Essay: How to Build a</p> <p>Seneca</p> <p>Plans for this boat may be found at:</p> <p>Pacific Power Dory</p> <p>To begin building the Seneca, or anySpira International framed boat, astrongback jig is required. This is simplya sturdy beam on which the frames andother elements of the hulls framing areset up and temporarily attached to holdthem in position until the adhesive hold-ing the frame together is cured.</p> <p>The frames need to be set up on thestrongback, in most cases, higherthan the strongback to establish thefair curve of the bottom. (Some boatshave a completely flat bottom.) Theblocks need not be as elaborate asthese, but these work very well andmake the following tasks mucheasier.</p> <p>When the frames are set upon the strongback, it lookssomething like this.</p> <p>The keelson isadded next to theframes. Note thatthe cutout in theframes is widerthan the keelson.This is intentional,to create limberholes so that bilgewater can moveback and forthbetween frameseasily.</p> <p>Notches in theframes are cut andthe longitudinalelements areadded. After thekeelson, the chinelog is the first to beinstalled. It runsthe length of thebottom and sidejoint.</p> <p>The same procedure usedfor the chine log is usedfor the sheer clamp, thelongitudinal elementrunning on the top of theframes. (Actually on thebottom in this viewbeacuse the boat is up-side down.)</p> <p>The boats framing is faired, thatis, cut to follow the fair curves ofthe side and bottom panels, so thatthe plywood planking will have anice flat surface to lay against andget bonded.</p> <p>The framing itself is used as apattern to cut out the plywood. Itdiesnt really matter if the bottomplywood or side plywood is at-tached first, but it does matter thatwhichever is lain first, it must beaccurately trimmed to be flush withthe framing surface so that the nextpanel will cover the end grain ofthe first.</p> <p>Where the plywood meets, buttblocks made of scrap plywood arebonded to the inside of the joint,and screws run through the outerply into the butt block to ensure asecure doubled joint.</p> <p>You can scarf splice the plywoodtogether, but it is a lot more workand not really necessary. Thesesimple butt-joined panels areamply strong for anything youboat is likely to come across.</p> <p>Here, you can see the meticu-lous detail this builder usedwhen creating the plankingjoints on the bow of the boat.Acheiving this level of crafts-manship is not difficult, it justrequires patience and atten-tion to detail.</p> <p>Once the planking ison, the hull startslooking like it isreally a boat.</p> <p> Once the epoxy orpolyurethane gluesets, the hull becomesrigid and you canloosen or remove itfrom the strongbackjig.</p> <p>The outside of thehull is prepped byfilling any counter-sunk screw holes,any seams at the buttblocks, and any otherfinsih defects. Pa-tience here pays offin the long run.</p> <p>When this part o fthe hull is complete, most builders elect to cover the hull with</p> <p>The hull is then flippedover and removed from thestrongback. The inside issaturated with epoxy resin.No fiberglass cloth isneeded. The epoxystrengthens and seals thewood making the boat bothsturdier and more rot resis-tant.</p> <p>fiberglass and epoxy resin.Two layers of 6 oz glasscloth and epoxy laminatingresin are normallyrcommended.</p> <p>Though not spe-cifically called outin the plans, thisbuilder elected toadd an inwale onthe inside of theframes. This givesthe hull a morefinished appear-ance.</p> <p>Strip deckingwas added to thishull. Left bright(varnished,) thewood appearanceis elegant andtraditional. Thesestrips are at-tached directly tothe topside of thelower frrameelements.</p> <p>Next the variousaccessories areadded as desiredby the builder.Cleats, motor, oarlocks, and in thiscase swivel seats.finish the hull andmake it seaworthy.</p> <p>Ahhhh... This is what its all about!</p>