Risto, in addition to what Jay and Brian said, the following may be worth mentioning...

First (unless I've totally missed the "boat", which wouldn't surprise me or my wife), gluing the strips together is temporary, in that you are just trying to have the boat hold it's shape until the glass can be applied. At that point, the strength is in the glass, not the glue.

Second, any yellow glue, if applied properly (good mating surfaces, tight joint under pressure while the glue sets, etc) will be stronger than the surrounding wood. I've tested this myself, just for fun. With proper use, you can beat the heck out of something you've glued, and the wood around the joint will bust before the joint itself does. So, who cares if the poly glue is stronger... by the time it matters, the wood around all of the joints would have disintegrated anyway.

All that stuff above, of course, is with the understanding that the "thing" will be encased in glass. If you want to talk about paddles, roof rack cradels, or anything that might not be glassed, the scenario changes, particularly in regards to waterproofness, holding a finish, UV degredation, etc. But, I don't know enough to get that specific in those areas.

I hope you find something in there useful.

Rick