Before we discuss Three Men in a Boat (1956), the movie, I'd like to ask, do you know of Three Men in a Boat, the 1889 novel by Jerome K. Jerome? Science fiction fans of a certain age may remember it from Robert Heinlein's Have Spacesuit - Will Travel, where Kip's father reads it obsessively, drawing deep philosophical inspiration from the incident with the pineapple tin and no opener. Younger SF fans may be more familiar with Connie Willis' tribute, To Say Nothing of the Dog.
If you haven't heard of this book, then this movie may not be for you. On the other hand, if you are a big fan, you may be disappointed to find that the movie only vaguely resembles it. So be warned.
Sometime in the 1890s, three men (and a terrier named Montmorency) who take a rowing holiday on the Thames. They are a handlebar mustached Nigel Bruce type, trying to get away from his fiancee's mother (Jimmy Edwards), a henpecked husband (David Thomlinson), and a bank teller and ladies' man, Laurence Harvey. They are rowing from Hampton Court to Oxford, and sleeping out under the stars (or drenching rain, since it is England). There are misadventures, slapstick, sunny days and cute girls. There is, indeed, a struggle with a tin of pineapple.
Once again, we have a gentle little English comedy. If you like that sort of thing, if you've read Three Men in a Boat, but aren't a fanatic, or if you want to see Laurence Harvey in a non-bongo-related role, give it a look.
In conclusion, the 1975 TV movie version, written by Tom Stoppard, starring Tim Curry, Michael Palin and Stephen Moore sounds amazing.