like a bunch of unruly schoolkids
And that's exactly what they were ;-) You had the bad luck to share the trip with one sort of field trip or another (could've been a farmers' co-op on a day trip for example)... All these people were probably as happy as kids to be away from home, away from work, away from everyday responsibilities. And as they knew no other way to relax than drinking and shouting, they drank and shouted. This is not to excuse them in any way, but I can understand them (sort of). The only thing is, they should have reserved the boat for themselves, and not inflicted their infantile joy on the rest of the world at large ;-)