I suspect a large part of the problem is a smooth consistant even stroke from each oar, at least that's what if figure is my issue. I would guess if you put a member of the local rowing team in the boat he would go straight. I was told the two hull of the pontoon would make it twice as difficult to row straight. I'm guess Normand is on target with the tight pressure, secured straight in the frame advice also. I have also wondered about the position of the seat, is the center of the boat the best location?