Thanks for the info. Yes it will mostly be use I flat water and maybe waves here and there.. No white water at all. Only use my raft for lake fishing really.Round and Square Bent Metal Tube | The Chicago Curve
For fishing on moving flatwater, I bet you'd be fine. And if the frame folds, at least you're in flatwater.
If you've got waves and rapids and such to deal with, the strength of round tube might be worth the awkwardness of mounting stuff to it.
*Built an uber simple fishing frame for my raft and I'm currently using 1 inch conduit tubing. I'm thinking of now using square tubing so that I can easily install rails to mount accessories on. Any problems I might run into using square tubing?