After having done photos at events, I have once decided NEVER to photograph people while they are eating any more. You have the hardest of time getting a flattering photo when they chew or have their food in one cheek, or just shovel some more into their mouths. Not saying that you captured some such extremely unflattering situations, only was I thinking that when I saw that you also took photos of the guests on board while eating...
It is, of course, very difficult to really separate one clear subject from the rest with so many people walking about, being in the picture, moving, jostling, and generally being so close together. But it'd be more pleasing if there had been no stray ellbows in your pictures, or hints of the next person at the very edge of your frame (3). But, like I was saying: this is very hard to achieve in a situation like the one you came upon. Careful cropping at home could do the trick, though, maybe. With some.
All in all I like the first and last best, as I like how the light lightens up the drinks in 1, and you captured some of the atmosphere for the crew, and the last because you have ONE clear subject (and one stray ellbow, but that needn't stay), he's alone with his raki (without the dot, only my computer can't type that), deep in thought, nicely separated from the background.
All in all I like the fact that I seem to know where they have gone, as I may very well have gone past all the sights they passed on a boat, myself, too ;-).