good weather days

7/18/2019 Good Weather Days

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1. Good Weather Performance Speed

There are two kinds of “performance speeds” assessed by weather routing companies. One is theGood Weather Performance Speed, analyzed based on the good weather analysis methodology withthresholds taken from the vessel Charter Party, and the other is the Entire Voyage Performance Speed,which applies a weather factor. In maritime Arbitration, the former is the only acceptable method. Thelatter is a useful performance analysis tool for owners' and operators' scheduling and other businessdecisions, but not for legal purposes.

The Good Weather Performance Speed is assessed based on a good weather analysis method asset out in two English Law precedents, namely: LMLN 357 (1993) B.P. Shipping Ltd. v. Exmar N.V.(The Gas Enterprise) - Court of Appeal (Lloyd, Butler-Sloss and Roch L.JJ.) - 23 June 1993 and TheDidymi [1988] 2 Lloyd’s Rep 108. This methodology is widely accepted in London legal circles. As both judgments were made in the Court of Appeal, this means the judgments are binding on all lowerEnglish Courts.

London Maritime Arbitration Award LMLN 549 (2000) explains the method as follows:

The appropriate approach was as follows (see The Didymi [1988] 2 Lloyd’s Rep 108):

(i) The vessel's performance should be assessed in good weather conditions (generally Beaufortwind force 4 or below or as defined in the Charter Party) on all sea passages from sea buoy tosea buoy excluding any slow steaming at charterers' request.

(ii) If a variation of speed from the warranted Charter Party speed was shown, the varianceshould be applied with all necessary adjustments and extrapolated to all sea passages and in allweather conditions (excluding slow steaming at charterers' request).

(iii) If a variation of fuel consumption from that warranted in the Charter Party was shown thevariation should be applied with the necessary adjustments and extrapolated to all sea

passages and in all weather conditions (including slow steaming at charterers' request).

Complying with the method, Weathernews analyzes the average vessel speed during good weatherdays as stipulated by the Charter Party and applies the appropriate good weather current factor, unlessotherwise stipulated in the Charter Party.

Therefore: Good Weather Performance Speed = Good Weather Average Speed – Good WeatherCurrent Factor

The accuracy of current measurement now is very high indeed and Weathernews no longer usesPilot Charts which are deemed obsolescent - please read point 5. ‘Current Factor’

It should be noted that in this analysis a “weather factor” (as used in entire voyage analyses) is notemployed.

To complete a ‘Good Weather Analysis’ all ship noon positions for all days of the voyage areneeded.



2. Good Weather Analysis Method

A Good Weather Analysis is the correct methodology for speed & bunker analysis calculations as setout in two English Law precedents, namely: LMLN 357 (1993) B.P. Shipping Ltd. v. Exmar N.V. (TheGas Enterprise) - Court of Appeal (Lloyd, Butler-Sloss and Roch L.JJ.), and The Didymi [1988] 2Lloyd's Rep 108. This methodology is widely accepted in London legal circles.

Step 1: Assessing Which Days are the Good Weather Days

The first step of a Good Weather Analysis is the selection of good weather days. This selection isbased on a 6-hourly analysis which depicts weather / seas / current conditions experienced by thevessel. The analysis process follows:

1. The overall voyage is separated into individual days, where a “day” is taken to be theperiod of time between consecutive daily noon positions. Therefore the duration of a daycan range from 23 to 25 hours depending on the direction and number of time zones avessel passes through.

2. The weather / seas at 00Z, 06Z, 12Z, and 18Z for each day is analyzed and categorized

as either “Good” (within the fair weather definition) or “Bad”. 3. If the majority of the above time slots (over half the day) are categorized as “Good”

regarding wind force and sea height, then the whole day is considered a fair weather day- i.e. ¾ of the day.

Step 2: Analyzing the Vessel Speed on the Good Weather Days

The second step of the good weather analysis method is to calculate the ship performancespeed. We assess the ship performance speed by calculating an average speed in good weatherperiods, and taking into account a current factor during the good weather periods, unless otherwisespecified. The equation is:

Good Weather Performance Speed = Good Weather Average Speed – Good Weather CurrentFactor.

London Maritime Arbitration award LMLN 670 (2005) explains this as below.In the event, the good weather performance of the vessel (between 0130 on 19 and 0200 on 20November) could be assessed in round terms as 12.21 knots (305.3 miles ÷ 24.50 hrs less 0.25 knotscurrent factor) against her warranted performance speed of 13.00 knots (13.50 less 0.5 knots for“about”). There was therefore an under -performance.

The tribunal had accepted the overall mileage steamed as 5,224.60 nautical miles. Thus, had thevessel steamed throughout at 13.00 knots she would have taken approximately 401.89 hrs (5,224.60nms ÷ 13.00 kts). At her actual good weather speed of 12.21 knots she would have takenapproximately 427.89 hrs (5,224.60 nms ÷ 12.21 knots) - a loss of approximately 26 hours.



3. Good Weather Analysis with “No Adverse Current”

If the good weather definition has a “no adverse current” stipulation in the Charter Party, currentsshould be taken into account in selecting good weather days, as demonstrated in London Maritime Arbitration award LMLN 723 (2007).

The charterers first calculated the vessel’s average speed and consumption for the voyage during

periods when the weather was up to Beaufort Force 4 and the vessel was not encountering a headcurrent. The average good weather performance was then applied to the full sea passage from seabuoy to sea buoy (as in The Didymi [1987] 2 Lloyd’s Rep 166).

This means that any day where the vessel experienced, on average, negative currents, has to beexcluded from the good weather analysis period.

CORRECT METHOD

Once the good weather days are selected (for example, all days that were equal to or less than BF4and/or DSS3 and with no adverse currents) then the performance speed of the vessel can becalculated.

Ship performance speed = Average Speed - Current Factor

Good Weather Days

DATE GMT

POSITIONS

DISTANCE(NM)

WINDSIG.

WAVE(M)

Daily Av.

Current(KTS)

LAT LON DIRSPEED(KTS)

BF

4.8 3:00 6.17S 81.23W

4.8 6:00 5.97S 81.28W

285.5

SSE 15.0 4 1.2

-0.41

4.8 12:00 4.78S 81.55W SSE 17.0 5 1.2

4.8 18:00 3.60S 81.50W S 13.0 4 1.0

4.9 0:00 2.44S 81.37W S 10.0 3 1.2

4.9 3:00 1.48S 81.27W

4.9 6:00 1.30S 81.24W

275.0

SW 11.0 4 1.1

-0.10

4.9 12:00 0.20S 81.05W SW 13.0 4 1.0

4.9 18:00 0.91N 80.86W SSE 15.0 4 0.9

4.10 0:00 2.05N 80.67W SSE 15.0 4 1.1

4.10 3:00 3.03N 80.50W

4.10 6:00 3.22N 80.47W 283.3 SW 13.0 4 1.1 0.10



4.10 12:00 4.38N 80.26W WSW 13.0 4 1.0

4.10 18:00 5.49N 80.06W SW 9.0 3 1.0

4.11 0:00 6.88N 79.85W SW 7.0 3 0.8

4.11 3:00 7.67N 79.67W

Good weather average speed = 11.80 knotsGood weather current factor = 0.10 knotsPerformance Speed = 11.70 knots

INCORRECT METHOD

Days having adverse current are NOT excluded from good weather period below which goes against

the Charter Party definition and therefore is incorrect.

Ship performance speed = Average Speed - Current Factor

Good Weather Days selected incorrectly

DATE GMT

POSITIONS

DISTANCE(NM)

WIND

SIG.WAVE(M)

Daily Av.

Current(KTS)

LAT LON DIRSPEED(KTS)

BF

4.8 3:00 6.17S 81.23W

4.8 6:00 5.97S 81.28W

285.5

SSE 15.0 4 1.2

-0.41

4.8 12:00 4.78S 81.55W SSE 17.0 5 1.2

4.8 18:00 3.60S 81.50W S 13.0 4 1.0

4.9 0:00 2.44S 81.37W S 10.0 3 1.2

4.9 3:00 1.48S 81.27W

4.9 6:00 1.30S 81.24W

275.0

SW 11.0 4 1.1

-0.10

4.9 12:00 0.20S 81.05W SW 13.0 4 1.0

4.9 18:00 0.91N 80.86W SSE 15.0 4 0.9

4.10 0:00 2.05N 80.67W SSE 15.0 4 1.1

4.10 3:00 3.03N 80.50W



4.10 6:00 3.22N 80.47W

283.3

SW 13.0 4 1.1

0.10

4.10 12:00 4.38N 80.26W WSW 13.0 4 1.0

4.10 18:00 5.49N 80.06W SW 9.0 3 1.0

4.11 0:00 6.88N 79.85W SW 7.0 3 0.8

4.11 3:00 7.67N 79.67W

Good weather average speed = 11.72 knots (843.8 miles / 72 hours)Good weather current factor = - 0.14 knotsPerformance Speed = 11.86 knots

4. Good Weather Definition missing parameters

For days to be selected as ‘Good Weather Days’, they must meet all parameters defined in the

charter party. The definition of what constitutes ‘good weather’ (the conditions under which thedefinition of the vessel's speed and consumption warranties are valid) varies widely from Charter Partyto Charter Party. Some definitions only mention wind speed; others mention wind speed, wave height,swell, current, sea surface temperature and more. Generally, the less terms are included in the CPdescription of what constitutes good weather, the better from a charterers' point of view.

When a Charter Party only mentions wind speed such as Beaufort Force 4, we do not take intoaccount other parameters such as wave height, swell, or currents. The Charter Party is the CharterParty and anything to be added as a factor for performance analysis should have been written.

This means high seas will not be taken into consideration even if the vessel encountered suchconditions. Likewise, even if the vessel encountered adverse currents which might have impeded thevessel's progress, the good weather days selected would include days with adverse currents.

London maritime Arbitration precedent LMLN682 (2006) shows that, the Charter Party good weatherdefinition is taken to mean exactly what it says, no more:Nothing was said in clause 29 about weather or sea conditions. The charterers said that that meantthat the owners warranted that the ship would perform under the charter at the stated speed andconsumption, whatever the weather. The owners said that, on the contrary, the warranties onlyapplied in perfect conditions, and that since between Algeciras and the Brazilian discharge port theship performed at 12.09 knots, ie "about" 12.50 knots, there was no breach.

Held, that the tribunal did not accept the owners' argument. In the tribunal's experience it was veryunusual to find such an unqualified warranty in a normal charter. Nevertheless, the tribunal did not seehow it could fairly read the relevant words in clause 29 as the owners suggested. The natural meaningof the words was that the ship was to perform at the stated speed and consumption throughout thetrip. If the owners had wanted to qualify their obligations in some way, they should have inserted

words such as the common “in good weather and smooth water”, or even “without guarantee”.Otherwise the words had to given the broad meaning argued for by the charterers.

(2006) 699 LMLN 1 opted for BF4 only when ‘good weather’ was described in the Charter Party: “[Details of the vessel were then set out] speed / consumption (under good weather and smooth seacondition): about 13.5 knots on about 79 long tons fuel oil 380 CST at 50 deg C under laden condition;no Diesel oil consumption during normal steaming at sea …”



What weather and / or sea conditions were covered by the description “good weather conditions”?There was a dispute as to whether “good weather conditions” meant winds of force 4 or below or force3 or below on the Beaufort scale. Held , that the correct answer was winds of force 4 or below on theBeaufort scale. There was no absolute yardstick by reference to which one could measure what parties objectively intended by referring to “good weather conditions”. However, the figure of Beaufortforce 4 or below was so widely applied that unless parties expressly agreed another figure, theirobjective contractual intention could be considered to be to adopt the generally applied figure of force4 or below.”

6. Time Lost and Over-consumption Calculation

The concepts used in time lost and over-consumption calculations are explained in the “DIDYMI”case and the “GAS ENTERPRISE” case. The MV Gas Enterprise case (LMLN 357, 1993) explainsthem as follows.The first step in the exercise is to find the average speed for each passage in accordance with sub-cl(4) during period when the weather was force 4 or less. That established the speed (andconsumption) of which the vessel was capable during the passage in question and thereforedetermines whether or not the owners were in breach. To have included periods during which theweather was worse than force 4 at that stage of the exercise would have been unfair on the owners,

just as it would have been unfair to include periods when the vessel's speed was reduced by reasonof poor visibility or congested waters. Once the speed of which the vessel was capable in fair weatherhad been established for each passage, the warranty took effect. If the speed was less than thewarranted speed or if the consumption of bunkers was greater than the warranted consumption forthat speed, the charterers were entitled to recover compensating over the whole of the passage inquestion, not just that part of the passage which was performed in good weather. If the bad weatherwas such as to effect the vessel's performance on any particular passage, the owners could take thatinto account in reduction of damages. The warranty was an undertaking as to the speed at which thevessel was capable of performing, not the speed at which she would actually perform.

This indicates that the correct way to analyze a vessel's performance is to separate out the periodswhen the vessel is sailing in good weather conditions and calculate the vessel's good weatherspeed/consumption. This can then be applied to the overall period as follows: The good weather speed

and consumption are applied to the whole voyage and the time / consumption for the whole voyage atthe good weather speed/consumption can be compared to the time / consumption for the whole voyageat the Charter Party speed/consumption. The difference represents a time loss or fluel over -consumption or under - consumption.This methodology can be seen in several Arbitration judgments (an example per below):

TIME LOST

Example 1:LMLN 723 (2007)

Comparing the time required to perform the voyage of 10,900.50 miles at the warranted speed of 13

knots (838.50 hours) with the time taken at the average good weather speed of 12.28 knots (887.66hours) the vessel lost a total of 49.16 hours between Tubarao and Majishan, equivalent toUS$130,819.28, net of address commission but including brokers' commission payable, according toclause 27, by the owners to the brokers involved.

To summarize:Total distance: 10,900.50 nmGood weather distance: 1162.80 nmGood weather time: 95.0 hoursGood weather performance speed: 12.28 knots(Note: It looks like this is a miscalculation, because 1162.80 / 95 = 12.24 knots)



It should be noted that good weather current factor was discussed, but it was rejected because ofno proof of the same was submitted ? Weathernews can always provide evidence.

Therefore time lost should be calculated;

Example 2:LMLN 670 (2005)

In the event, the good weather performance of the vessel (between 0130 on 19 and 0200 on 20November) could be assessed in round terms as 12.21 knots (305.3 miles ÷ 24.50 hrs less 0.25 knotscurrent factor) against her warranted performance speed of 13.00 knots (13.50 less 0.5 knots for“about”). There was therefore an under -performance. The tribunal had accepted the overall mileagesteamed as 5,224.60 nautical miles. Thus, had the vessel steamed throughout at 13.00 knots shewould have taken approximately 401.89 hrs (5,224.60 nms ÷ 13.00 kts). At her actual good weatherspeed of 12.21 knots she would have taken approximately 427.89 hrs (5,224.60 nms ÷ 12.21 knots) -a loss of approximately 26 hours.

To summarize:Total distance: 5,224.60 nmGood weather distance: 305.3. nmGood weather time: 24.5 hours

Good weather performance speed: 12.21 knotsGood weather current factor: 0.25 knots

Bunker Calculations

Bunker calculations consist of an over-consumption evaluation and a fuel saving evaluation, wherethe former applies an allowance of usually 5% upwards, but the latter does not give any allowance(unless otherwise specified in the Charter Party). Complying with maritime Arbitration standards, Speedand Bunker Analysis is not applied when there are no good weather days.



It should be noted that there are some other calculation methods, employing a ‘weather factor’ forthe entire voyage, but they are not accepted in maritime Arbitration. (Please see 8 “Weather Factor andEntire Voyage Performance Speed”.)

Nowadays almost all Charter Parties apply an “about” on speed and consumption with the word“about” before speed and consumption values, and/or a phrase ‘All details “about”’ in the vessel'sparticulars section.

It seems that owners and charterers generally agree on an application of 0.5 knots for speed“about”, but there are still some arguments regarding the consumption “about”. Weathernews' Speedand Bunker Analysis applies an allowance of 0.5 knots on speed, 5% on fuel over-consumption and noallowance on fuel saving when the Charter Party includes an “about” for both speed and consumption.

As English Law is about ‘damages’, there is no ‘damage’ to the charterer if they are having to giveowners credit for bunkers under-consumed. This interpretation is reasonable for both owners andcharterers. London maritime Arbitration precedent LMLN723 (2007) expressed the same idea asbelow. In this case, the consumption warranty stipulated in the Charter Party was 46 MT/day:With regard to the extent of the allowance to be given for the term “about”, although on someoccasions in the past, Arbitration tribunals had referred to allowances of less than 5% on bunkerconsumption, the current practice was almost invariably to apply an allowance of 5% unless therewere special circumstances. There was no reason to depart from that practice in the present case.

Accordingly, in considering whether the vessel had over performed, reference was to be made to adaily consumption of 48.3 mts, whilst in determining if bunkers had been saved, reference was to bemade to a daily consumption of 46 mts.

Over-consumption:LMLN 723 (2007)

The charterers calculated that on the days of contractually good weather conditions the vesselconsumed an average of 44.90 mts of IFO and 0.87 mts of MDO each day. Performing the entirevoyage of 10,900.50 miles on that daily consumption at the average good weather speed of 12.28knots the vessel’s voyage consumption would have been 1,660.67 mts of IFO and 32.17 m ts of MDO.Those figures were to be compared with consumption for the voyage at the minimum warranted speed

of 13 knots on a daily consumption of 48.3 mts IFO and 1.05 mts of MDO, namely 1,687.48 mts ofIFO and 36.68 mts of MDO. There was therefore no over consumption of bunkers. Was there asaving? Whether a speed of 13 knots or 13.5 knots was adopted, the vessel’s good weatherconsumption figure of 1,660.67 mts IFO and 32.37 mts MDO exceeded consumption for the voyage ata daily rate of 46 mts and 1 mt respectively. The vessel’s bunker consumption therefore neitherexceeded the maximum permitted nor fell below the level at which savings were made. In short, thevessel’s consumption fell within the permitted range for the voyage and gave rise to no claim or credit.

To summarize:Total distance: 10,900.50 nmGood weather distance: 1162.80 nmGood weather time: 95.0 hours(Note: It looks like this is a mis-calculation, because 1162.80 / 95 = 12.24 knots)It should be noted that good weather current factor was discussed, but it was rejected because of

no proof submitted.

http://weathernews.com/TFMS/services/opa/methodology/09.html








8. Weather Factor and Entire Voyage Performance Speed

The vessel's Entire Voyage Performance Speed is another Performance Speed utilized in weatherrouting operations, but it is at odds with English Law and therefore not preferred.

The vessel's Entire Voyage Performance Speed is determined from an average speed, a current

factor, and a weather factor of the entire voyage. The average speed is calculated as follows: Averagespeed = Total distance / Total time en route. Ocean current data at all points along the vessel's routeare analyzed to calculate how much effect each current had on the vessel at any given time.

The ‘Weather Factor’ is a numerical representation of the speed reduction experienced by the vesseldue to the wind and sea conditions it encountered. The weather factor can be determined by speeddown curves to determine how much the vessel would be affected by a given set of conditions. Thespeed down curve is applied to all conditions experienced throughout the voyage and the resultingspeed down is the weather factor.

One of the major drawbacks of using this method is that often times an accurate weather factor isnot provided because it requires a speed down curve tailored for each individual ship that takes intoaccount all characteristics of that ship, including load condition. Since this is not a realistic or feasible

solution, a generic speed down curve is employed and the resulting speed downs are adjusted by acertain percentage based on the vessel type. Provided a sufficient data set taken from many voyages,an accurate weather factor could be obtained by tailoring the reduction percentage, but suchmeticulous and detailed data sets are not usually available.

It should be also pointed out that the Weather Factor was rejected in a recent London Maritime Arbitration award, LMLN 738 (2008), as below:

Moreover, on the facts, the charterers were not entitled to make any deductions in relation to thealleged speed claim. The charterers' case was based on a number of days, some of which plainly fellto be excluded since the weather was at the acceptable limit on them, not below it. The charterers hadalso said that the deck logs should be ignored, and that a “weather factor” should be brought intoaccount in order to establish what the actual speed was. That approach was impermiss ib le .

As the two judgments in the Court of Appeal LMLN 357 (1993) B.P. Shipping Ltd. v. Exmar N.V.(The Gas Enterprise) - Court of Appeal (Lloyd, Butler-Sloss and Roch L.JJ.) - 23 June 1993 and TheDidymi [1988] 2 Lloyd’s Rep 108 both outlined the correct method to analyze a vessel’s performance(in good weather only) then this is binding on all lower courts and as such is the correct method to use.

FAQ’s

Q1. How to determine whether or not a vessel under-performed



Weathernews analyzes and selects the periods that can be considered “good weather days”according to the good weather definition in the Charter Party and then calculates the vesselperformance based on how the vessel performed on average within these “good weather days”. As per London Maritime Arbitration precedent LMLN 357 (1993):

“The first step in the exercise was to find the average speed for each passage in accordance with sub-clause 4 during periods when the weather was force 4 or less. That established the speed (andconsumption) of which the vessel was capable during the passage in question and thereforedetermined whether or not the owners were in breach.”

“Once the speed of which the vessel was capable in fair weather had been established for each passage, the warranty took effect. If the speed was less than the warranted speed or if theconsumption of bunkers was greater than the warranted consumption for that speed, the chartererswere entitled to recover compensation over the whole of the passage in question, not just that part ofthe passage which was performed in good weather.”

Thus any underperformance for a vessel during the good weather period would be extrapolated tothe entire voyage to arrive at the true loss for the charterers.

Q2. Shouldn't time lost be calculated only for The Good Weather

Period?

Weathernews' stance is to provide objective ship performance auditing reports based on Londonmaritime arbitration standards, using a good weather analysis method, as explained in English Lawprecedents such as the MV Didymi case [1988] 2 Lloyd's Rep 108) and the MV Gas Enterprise case



(LMLN 357, 1993). London Maritime Arbitration Award LMLN 549 (2000) explains the method asfollows:“The appropriate approach was as follows (see The Didymi [1988] 2 Lloyd's Rep 108):

- (i) The vessel’s performance should be assessed in good weather conditions (generally Beaufortwind force 4 or below or as defined in the charterparty) on all sea passages from sea buoy to sea buoy

excluding any slow steaming at charterers' request. - (ii) If a variation of speed from the warranted charterparty speed was shown, the variance should be

applied with all necessary adjustments and extrapolated to al l sea passages and in al l weather

condi t ions (excluding slow steaming at charterers' request).

- (iii) If a variation of fuel consumption from that warranted in the charterparty was shown the variationshould be applied with the necessary adjustments and extrapolated to al l sea passages and in al l

weather c ondi t ions (including slow steaming at charterers' request).”

Gas Enterprise case (LMLN 357, 1993):

“Prima facie the charterers were entitled to be compensated for any breach of that warranty. A vesselwhich could not comply with her contract speed or consumption in good weather was unlikely to beable to comply with the contract when the weather was bad. One would therefore expect sub-clauses

4 and 5 to provide the machinery for assessing compensation for any breach of warranty irrespectiveof the weather. There was no sensib le business reason wh y the part ies should have intendedthat the charterers should be comp ensated for under performance in per iods of goo d weather ,

but not in per iods of bad w eather .”

The extrapolation of a vessel's performance in good weather to the entire length of the voyage is thecorrect method for assessing damages due to the ship under-performance and / or over-consumption.

Q3. How are Good Weather Days selected?

The evaluation method applied by Weathernews is analyzed on a 6 hourly basis to determine a goodweather period is as follows:

1. The overall voyage is separated into individual days, where a “day” is taken to be theperiod of time between consecutive daily noon positions. Therefore the duration of a daycan range from 23 to 25 hours depending on the direction and number of time zones avessel passes through.

2. The weather / seas at 00Z, 06Z, 12Z, and 18Z for each day are analyzed and categorizedas either “Good” (within the good weather definitions) or “Bad”.

3. If the majority of the above slots (over half the day) are categorized as “Good”, then thewhole day is considered a good weather day.



When the good weather definition includes ‘no adverse current’ or an equivalent stipulation, step 3)above should abide by this stipulation by taking into consideration the current factor when selectinggood weather days: wind / sea conditions need to be within the good weather definition thresholds andthe average daily current factor must be zero or a positive value. If this stipulation is neglected, theanalysis results in incorrect conclusions.

Q4. Is the Good Weather Definition used by Weathernews correct?

The correct good weather definition can only be verified by a look at the charter party. This is usuallynot provided by the operators who order service from a weather routing company. Therefore, routingcompanies must rely on the correct interpretation of the charter party good weather definition providedby the operator. When the interpretation of the good weather definition comes into question, a routingcompany may request a scanned copy of the charter party sections detailing the good weatherdefinition.

Q5. Does BF4 imply DSS3 even when it is not explicitly stated in the

Charter Party?

Usually, the correct good weather definition can be verified by analyzing the charter party goodweather definition, but there are some cases when the charter party itself is not clear enough andcauses disputes. One example: The charter party good weather definition is up to and including BF4;there is no mention of wave height thresholds.

In such a case, it could be argued that, as there is a causal relationship between winds and waves,the good weather definition for a charter party that only states BF4 should also include the thresholdDSS3 for waves. Owners may take this point of view if it suits the limitations that sets on the number ofdays selected as good weather days. Charterers may argue that the charter party good weatherdefinition should be read exactly as it is and needs no interpretation: If it does not state a wave heightlimit, then there is none. Sometimes owners and charterers can find a way to negotiate on the correctreading of the charter party. But sometimes these disputes go to arbitration.

In Arbitration, good weather definitions have in the past been interpreted very strictly as meaningexactly what they state, and no more. One example for such a case is 2006 LMLN 682:Nothing was said in clause 29 about weather or sea conditions. The charterers said that that meantthat the owners warranted that the ship would perform under the charter at the stated speed andconsumption, whatever the weather. The owners said that, on the contrary, the warranties onlyapplied in perfect conditions, and that since between Algeçiras and the Brazilian discharge port theship performed at 12.09 knots, ie “about” 12.50 knots, there was no breac h.

Held, that the tribunal did not accept the owners' argument. In the tribunal's experience it was veryunusual to find such an unqualified warranty in a normal charter. Nevertheless, the tribunal did not seehow it could fairly read the relevant words in clause 29 as the owners suggested. The natural meaningof the words was that the ship was to perform at the stated speed and consumption throughout thetrip. If the owners had wanted to qualify their obligations in some way, they should have insertedword s such as the common “in good weather and smooth water”, or even “without guarantee”.Otherwise the words had to given the broad meaning argued for by the charterers.

This is a very strict interpretation, and it was surely a painful reminder that, as it stands, the risk ofsigning unclear charter parties lies with the signatories. Weathernews therefore strongly urge allowners and charterers to ensure that the contracts they sign are as clear as possible.

Q6. The Good Weather Period for this voyage is too short. Surely it

can not be sufficient?



The shortest allowable good weather period for a good weather analysis in London arbitration was24.5 hours. It is important that charterers understand this condition for the good weather analysis andthat shorter time periods are not sufficient.

If the vessel does not perform to the Charter Party warranted speed & consumption for 24 hours orlonger in good weather during the voyage (excluding periods of bad weather, off hire, periods of slowsteaming at the Charterer's request, canal transit etc…) then there must be a good reason given by theMaster for the speed reduction.

The award 670 LMLN 1 (2005, London Arbitration 15/05):In the event, the good weather performance of the vessel (between 0130 on 19 and 0200 on 20November) could be assessed in round terms as 12.21 knots (305.3 miles ÷ 24.50 hrs less 0.25 knotscurrent factor) against her warranted performance speed of 13.00 knots (13.50 less 0.5 knots for“about”). There was therefore an under -performance.

The tribunal had accepted the overall mileage steamed as 5,224.60 nautical miles. Thus, had thevessel steamed throughout at 13.00 knots she would have taken approximately 401.89 hrs (5,224.60nms ÷ 13.00 kts). At her actual good weather speed of 12.21 knots she would have takenapproximately 427.89 hrs (5,224.60 nms ÷ 12.21 knots) - a loss of approximately 26 hours.

The calculations shown above indicate that the good weather period during a journey of well over400 hours was only 24.5 hours. Important to note: When the good weather period is less than 24 hours,it would be seen as insufficient.

(2007) 718 LMLN 3 London Arbitration 9/07“As to whether the voyages of less than 36 hours duration could be taken into account for the purposeof assessing the vessel's good weather capability, the charterers had conceded that very shortvoyages of less than 24 hours duration should not be taken into account. However, the chartererswere correct in contending that the vessel should have been able to achieve her warranted speed ingood weather on any voyage of 24 hours of more.”

As the above stated, voyages of 24 hours or longer should be included in performance calculations.

Q7. Can bunker under-consumption be offset against time loss

and/or other bunker over-consumption?

Offset of fuel savings against under-performance is a standard procedure in London Arbitrationcircles unless the Charter Party stipulates otherwise. There are four Arbitration awards relevant to thisissue which conclude that off-set is allowed.1980 LMLN 17

Held, that the owners were entitled to compensation for the difference in fuel consumption. When thecharter had been drawn up in 1973 and entered into in July, 1974, fuel prices had been relativelyunimportant: prices had risen to such an extent in the meantime that saving on bunkers could be moreimportant in financial terms than saving time. Bearing this, and the terms of the charter, in mind, it was

not incongruous if the charterers only received compensation for excess fuel consumption if thevessel was slowsteaming, while the owners received compensation for reduced fuel consumptioneven when she was slow-steaming.1987 LMLN 188

Held, that to the extent that the charterers' claim had been put as one for damages for breach ofcontract, the owners were entitled to credit for any under-consumption of fuel oil when the charterers'damages were calculated.2002 LMLN 587



Held, that there had been an over-consumption as contended for by the charterers, but the tribunalwould agree with the owners that the charterers' claim had to lie in damages, and that in calculating it,credit had to be given for any savings in time or fuel oil consumption. .... In the present case, it wassufficient to say that on any view the lower than warranted consumption of fuel oil substantiallyoutweighed, in terms of the value of the bunkers in question, the over-consumption of diesel oil. Thus,although there was a breach, there were no damages and the charterers' claim had to fail.2007 LMLN 718

Held, that dealing, first, with the cargo heating point, the owners' case was that on those voyageswhere heating did take place less fuel was used in cargo heating than was warranted and thereforethey could set that off against any over-consumption in other respects. All the charterers had done, intheir calculations, was to give credit for the fuel actually used in heating............................

Therefore, the tribunal concluded that any under-consumption in cargo heating, whether at sea or in port, should be credited against over-consumption or under-performance at sea measured byreference to the relevant warranties.

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