It sounds an attractive idea, I admit.

I suspect one problem might be balancing the single-player and multiplayer options: realism dictates that rowing with multiple players would be faster but that would also be an annoyance for solo players.

Originally posted by zxmuffin:

I'd like to have one set of oars for smaller boat so single person could handle it and multiple sets for long boat so people traveling in group could use them simlutaniously and maybe even synchronize their strokes in order make it work.

And that would certainly be a partial solution but, even solo, a longboat becomes very useful in mid-game.