21GT Hull Speed

[Rick]

Does anyone know what the 21GT hull is capable of speed wise. Thanks Rick

[oldLenny]

I don't have a clue, but this fellow seems to think that 72MPH is available. Give him a call and see if that was GPS/Radar or just a speedo and what the 454 has done to it.

http://adcache.boattraderonline.com/6/9/4/19301694.htm

[jwright]

I am not sure what the highest speed that a 21GT can go (safely!)
I have a 1976 21GT, 280 TRS package (350 chevy)with upgraded exhaust, ignition, intake, carb... 21" prop, I run 54 mph at 4500 rpm. That works out to 8.5% slip which indicates that the hull is running very efficiently. So that is just a data point that indicates that the hull is great in the mid 50's.
My boat is very stable at that speed, so I can easily beleive that a big blck would run well at higher speeds. Check out JamesBond, he is redoing one right now with a BIG engine!

[Jamesbon]

I'm sure you could reach 100+ with the right HP. Not sure if I'd want to be in it though eek.gif

Mine ran stable and solid as a rock with no bad tendencies @ 55-59 mph with a 383ci and Volvo drive.

I would guess you're safe up to 80'ish...??? I'm hoping for 85 right out of the box with the ASD 6 and 510 ci....