Originally Posted by Projectile
Because frankc mentioned that the hook can become more pronounced under power, this last pic shows what a little gentle push in that region can do.
I think that this is very likely to be the cause of my problems. When this is the cause, the more one accelerates, the more the bow gets pushed down, which is exactly what I experience.
Now, what is the solution? Whatever it is, it'll have to wait for spring ...
You can't really diagnose a cupped hull on an inflatable out of the water. And you can't see the shape of the hull underway. But your cup seems pretty pronounced, to the point where its obvious just sitting still - although its hard to know if the trailer bunks are doing on the dry what water does underway.
There are 2 solutions:
1) make the floor boards longer to take up the slack in the fabric and uncup the hull. Some sort of spacer might work, but only if the tubes are long enough that the extra floor board length can actually stretch the hull fabric enough to remove the cup at the transom.
2) return this brand new boat to the dealer. Its defective from the get go and you shouldn't need to be modifying it to make it ride right without bow steering.
I would not waste your money on a different prop, that will not cure the bow steering which is due to the defective hull.