boat tilt and pulling

[Logan1500]

I need some advice.

I have a 17 foot Larson v-hull run-a-bout that when going medium to WOT speed, tilts to the left and pulls slightly.

Previous owner has put what is commonly referred to as "whale tails" on the outdrive. Could this be the reason it does this or is it more serious?

Thanks for looking.

[gonzo]

I don't like those tails. In my opinion, if the manufacturer didn't install a bigger cavitation plate is because it doesn't improve anything. You should have a trim tab, kind of a little vertical fin, in the aft part of the cavitation plate. Often it is also the zinc. To adjust it, turn it to the side the boat pulls. It may take a few tries.

[Corpus Skipper]

Many many many tries! The hull tilting can be corrected with hull trim tabs.

[pungolee]

Sounds to me like your motor is mounted off center,assuming your whaletail was installed correctly.Also after checking this make sure heavy items like batteries and fuel cans are balanced to either side.

[gonzo]

Yes, a motor off-center or tilted would also do that. If you correct the problem at one speed with the trim tab, it will be worse at others. You can check it by measuring the distance from the bracket to the sides and that the keel and the lower unit line up.

[Logan1500]

Thanks for the input.

My boat is an I/O, so I would assume the motor is centered.

If I re-position people and weight around it levels out.

Could someone tell me more about Hull Trim Tabs?

Thanks for the help.

John

[Corpus Skipper]

Could someone tell me more about Hull Trim Tabs?
These are usually stainless (sometimes aluminum) plates that extend from the transom even with the after planing surface of the hull. There are hydraulic and manual versions. Hydraulics obviously allow you to alter the trim angle while running, while manual tabs are bolted down in position and require you to loosen the bolts to change the angle. These are usually found only on small skiffs. Hydraulic tabs are great because as people move around and change the trim while running, you can adjust the boat back to level. Bennett, Quicksilver, and Lenco are three manufacturers that I know of.