Hi Doug, just dragged out the book I have 'The sea Shall Not have Them' It's funny how things are different between the book (1954), the movie and the re mastered copy. In the book the ASR boat is no 7525 (unknown type, but on the cover looks like a Maiami ), in the movie it's a British Power Boat 'Hants and Dorset'with the number 2561. On the cover of the remastered movie the boat is a 100 series HSL with the number 2561 which is totally incorrect as they only went from 100-121. Much poetic licence and lack of research methinks.
Could have been a lot more accurate as the boats were mostly all still in use back then.
The original movie is on Youtube as well which is great (obviously not a big budget movie though, as the acting and scenes are pretty crap) but the boats save it. Pics are a few shots from the movie , book and remastered cover.
The author of the book should have known better as he served on the ASR boats in the war.