However, whether in or on, it wasn't an appropriate expression in that context.-haha -all good fun though.

As for semantics, "on the boat" may mean which side you are taking in the more active part, just imagine two warships trying to sink each other in a war. "In the boat" may refer, as you state, to the kind of situation are in, and thus may refer to the more passive aspect of the same situation. I was referring to the more active aspect, that's why I decided to use "on".

However, I admit that "in the boat" may be the more common usage in native English. Things like that are what you may call set phrases having been used by a certain native language community for a long time. Hard to say whether they are "right" or "wrong" in terms of the prepositions used. It would probably right to say that usage X may be uncommon while usage Z is.

I think you originally meant to say "you got the wrong end of the stick..........? Yep, don't forget "we are in the same boat" can only refer to an undesirable situation- and never "we are both rich and happy and in the same boat...that would not do at all....common usage should be adhered to otherwise meanings become fractured.