I've got a Yam 280 with a 6hp longshaft 4 stroke Merc. There is enough room for me and my two kids, but can't get it to plane with the three of us on board at the same time. I might add that I'm a weighty 19 stone and with kids are 14 and 10 if that helps any. I guess the longshaft outboard doesn't help either
But with just me on there it flys along pretty good.
I think the Yams where made by Zodiac and are made from the longer lasting Hypalon rubber. I'm pretty sure the 260 might only be rated for a 4hp BTW.