It kinda felt like an attempt to mix "Dead Calm" (1988) with the Big-Brother-y-like "My Little Eye" (2002)...

... and the slightly less humorous version of "Very Bad Things" (1998) (remember how in that film a woman "accidentally" died/got accidentally "killed" during sex) with a little bit of "Shallow Grave" (1994) on the side, not too bad for what its worth but mostly rather uninspired and middle of the road B-grade-like British boat thriller entertainment.