Annoying porpusing..........
#1
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Annoying porpusing..........
Has anyone one experienced the bow of their boat nose diving to the left under acceleration ? Its in a Carrera ss8M with a single big block.Just started doing it after new engine. About 700 hp and 700 F/P torque. Also, the boat is porpusing after 60 MPH now. Its really annoying. I would assume the nose diving is from the torque, but how do I correct it ?
#3
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My 24 will "roll" to the port side under acceleration a bit. At WFO run the port tab just a touch lower and BARELY drag it to keep the boat level. 700 hp is a lot of power. More torque=more roll. If the bow is "diving" you may have the drive trimmed in too far. Try trimming it out a bit.
My boat will also porpoise if I don't use the tabs just a touch. Some props are better than others.
What prop are you running?
My boat will also porpoise if I don't use the tabs just a touch. Some props are better than others.
What prop are you running?
#6
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Its a 28 bravo 1. The prop is actually alittle too big I think. But I tried a 26 bravo yesterday and the " torque roll" was worse. I think I need to try a 5 blade prop to lift the hull out of the water more. Less drag, less roll ? Maybe? Im going to talk to Hydromotive and bblabes today to see what they say. Thanks for the advice.
#7
As far as the rolling goes, it is a light narrow beam boat, even my 24 with a 225 outboard does it under acceleration with all props except a 23 mirage, just drop the tab a bit, and trim it up. Porpoising can be helped with weight transfer, drive height, or prop selection.
#8
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Ive tried dropping the trim tab, that didnt do much at all. Driving this boat above 60 MPH can be a handful. Its not even fun. Someone needs to do some tricky prop work I think. I mean, Im not the first person to put a motor like this in this style boat. I will stay on it until I find the answer!
#9
Ive tried dropping the trim tab, that didnt do much at all. Driving this boat above 60 MPH can be a handful. Its not even fun. Someone needs to do some tricky prop work I think. I mean, Im not the first person to put a motor like this in this style boat. I will stay on it until I find the answer!
#10
Check the hull for a hook on the bottom, I had a 33 avanti with stock 454 mags, when I put in 540s with blowers about 900hp each, the hull acted the same way as yours is, found the problem to be a hook in the hull, when fixed it rode great, the hook will act as a trim tab pulling the bow down.