Hmm. The long-drowned patriot in me wants to advocate for In Which We Serve, and also for The Yangtze Incident (possibly the first movie I went to see without either parent in tow; it was a birthday treat, in a bizarre double bill with one of the St Trinians movies, and I forgot my then-very-new glasses and had to watch the whole of the first film in a blur, until my dad came hurrying down the aisle with my specs and Alistair Sym leaped suddenly into focus). The first of course is about a ship being sunk, and the second is about a ship being stranded mid-river and having to retreat: both continuing that splendid British tradition of finding triumph in defeat.

I might also want to make a case for The Life Aquatic with Steve Zissou or possibly The Boat That Rocked, just because frankly this list could use a giggle.