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dave leeming
04-22-2002, 01:22 PM
I have a 1970 GT with a 454/ TRS. The prop is a Cleaver. The bow really bobs. Trimming helps a little but really slows it down. Is this typical of GT's? Will changing the prop make a large difference? :confused:

Sam
04-22-2002, 03:09 PM
If you don't have trim tabs think about putting them on. They will cure a lot of problems like yours.

Sam

CDMA
04-22-2002, 06:59 PM
As far as I know all Gt's have built in rocker making them more likely to porpise. I would first try a different prop. A mirage style prop should carry the bow better and reduce porpising. If this is not enough I would go ahead and add the tabs.

Chris

jwright
04-23-2002, 04:13 PM
I have a 21GT with a TRS and small block. It also porpoises without using tabs. The fastest speed is attained in my boat by putting tabs down just a bit, then trimming drive out alot. The rocker in the hull does make it it a difficult boat to trim out in flat water. BUT it is so nice in rough water! It just skips from wave to wave on the transom... never planting the bow.. I love it!

Rick
04-23-2002, 04:59 PM
Guys, I also have a 21 GT and have heard of rocker on the hull for a while. Just what is rocker? Thanks in advance oh knowledgable ones. Rick

CDMA
04-23-2002, 09:46 PM
Basically instead of the hull being straight the back part of the hull curves up. Like a rocking chair. Generally very small. To the magnitude of 3/8 " per 3 feet or so. We are not talking a huge difference and sometimes only noticeable with a straightedge.

Chris

Formula Jr
04-24-2002, 03:00 AM
I could try to es'plane rocker but Brownie would just shoot it all to hell anyway. :D

think of booty on the end of your boat. Thats rocker. Hook is more like Laura Flynne Boyle. :D