The Warranted Ship: Speed and Consumption Claims

"She was warranted about 14 knots on about 25 tonnes, she made 12.5 on 27, so the claim is arithmetic." That sentence is spoken in chartering departments every week, and the arithmetic in it is the last thing that happens rather than the first. Every load-bearing word was somebody's judgement, and most of those judgements were made months earlier by whoever typed the recap: what "about" buys, when the ship had to be capable, which afternoons count as good weather, who owns a current that ran the ship's way, and whose account of the weather a tribunal will believe. On this course's own twenty-day voyage, a constructed passage built to teach the method rather than a real ship's, those words move the claim between USD 34,929 and USD 72,509. Nothing about the ship changes across that range.

So the course prices them, one at a time. Lesson 1 takes a real fixture recap apart into the four things that carry the money: the customary half a knot and five per cent, the double-about question and the caveat almost nobody quotes, whether the warranty is continuing or speaks only as at delivery, and what "without guarantee" does to everything that follows. Lesson 2 draws the good-weather window and finds that fifteen of twenty days fall out, for four different reasons, one of them nothing to do with the weather at all. Lesson 3 is the counter-intuitive core: performance is assessed on good-weather days only, and the deficiency is then applied to the whole voyage, bad-weather days included, which is why a claim filed as five days' worth of hire is a quarter of what it should be. Lesson 4 is where the fights actually happen, the wording on current, and it prices the same passage three ways. Lesson 5 weighs a deck log against a weather-routing report, reads a preference clause for what it does and does not bind, names the third witness almost nobody has yet pleaded, and reads the four London awards of 2026 for what their summaries support. Lesson 6 reads one award, London Arbitration 7/25, end to end, from the free commentary on it, and is careful to say so in every sentence. Lesson 7 is the dearest lever: what a court actually did to one expert report, paragraph by paragraph, and how to state an uncertainty argument a tribunal can act on. Lesson 8 is the only lesson that stops the argument happening, and it ranks six drafting changes by what each one was worth.

Three required exercises run on one Excel workbook, the speed and consumption claim calculator, on lessons 2, 4 and 8. It carries a twenty-day laden abstract with the weather, the current and the fuel for each noon-to-noon day, and it applies the charter's own clause to them: change the Beaufort ceiling, the sea state, the swell limit, the current wording or the minimum length of a qualifying period, and watch the sample redraw itself and the claim move in dollars. The last exercise turns each open sentence in a recap into a price, so a superintendent can walk into a negotiation knowing which two lines are worth spending leverage on.

Three subjects are deliberately not taught here. Our ISO 19030 course owns the filter chain, and lesson 2 says only that the chain and the good-weather clause are the same idea wearing different clothes before pointing at it. Our course Currents and Water Properties owns why a uniform current adds no resistance, the along-track cosine and the sign conventions that produce 180-degree errors; this course takes all of that as given and asks the one question that course does not, which is who owns the benefit. Our course ISO 15016 & Speed Trials owns the correction machinery and the checklist for reading a trial report critically. And this is a course about arguing from numbers, not a legal textbook: every case is cited to a source you can open, no proposition is stated more strongly than its source states it, and where the law is unsettled the course says so and names the competing readings.

The opening lesson is free to read as a sample. By the end you should be able to read a performance clause and say what each of its words is worth on your own voyage, draw the good-weather sample and defend the way you drew it, run the tribunal's own extrapolation before anyone sends you theirs, decide whether the claim in front of you is large enough to be worth an expert at all, and write the two lines into the next fixture that would have stopped the argument before the ship sailed.