1978 craft boat porpoise

[cbryan70]

I own a 1978 skier and around 34 mph it begins to porpoise/bounce and gets increasingly worse. Does anyone have any ideas? i have a 13 x 13 prop. In the past years before i purchased the boat the shaft rudder and prop were all replaced and since it has porpoised. please help

[peason]

Newer boats have modified the hull to prevent this - some guys have done this on thier own - Search the thread. Or, you may want to look at adding an adjustable trim tab on the back - search Team Talk.