I would like to comment on not just the sponson issue which has been a problem and addressed but on my experience with effect of lengthening the hull
I think the difference in MY GT VS THE STANDARD 21 boat after comparing the boats closely has to do with the difference in tail weight vs weight on the front sponsons
The GT HULL was lengthened. The motor placement was not changed, ie lengthened behind the motor mounting.
Thus DECREASING THE TAIL WEIGHT AND INCREASING THE WEIGHT ON THE FRONT SPONSONS
So I think the front sponsons have to be modified to handle the increase in “weight”
So my GT with what is supposed to be the correct sponsons width angles the same as the standard( like Ron Z has described) still runs wetter than the standard boat.
BTW MY GT OVER ALL WEIGHTS LESS THAN THE NON GT BOAT.
So at least in my case I need to do something to my GT sponsons to handle the increase in the displaced front weight
So after racing my standard 21 at the Winter Nats, in the Spring some double sticky tape and wood are going to be experimented with on the GT sponsons and ski
DO MY GT IS A WORK STILL PROGRESS