The Deep remains a firm favourite of mine, all these years after having first watched it - the clear blue water, the gruff old sea dog (Robert Shaw), Jacqueline Bisset's wet T-shirt, the mystery of buried treasure in an ancient wreak. It's a classic. But what are some other good examples of this niche of film-making? Into the Blue isn't great, and Boy on a Dolphin is pretty hackneyed - despite the recompense of Jessica Alba and Sophia Loren, respectively, in swiming cossies. So what would other HTFsers recommend in this type of movie?