whats the biggest motor I can use

[bicyclejuju1]

I have a 2001 west marine 310 by Avon. Boat is about 12 feet. I am currently using an old Johnson 9.9 motor. It just doesn't seem to have the power I feel the boat needs. Then again its my first boat and I don't really know how fast this boat should even be running. I was wondering if going up to a 20 HP motor is a bad idea? As I go up in motor size and gain speed will I lose maneuverability? Will the front ride to high?

[jyasaki]

Spec on the current WM 310 RIB is 15hp max. Be aware that you may have problems with insurance if you exceed the mfgr's max hp rating.

Power on a boat is kind of weird; up to a threshhold, you'll gain speed, but past that you generally add lots of hp for a small gain. Weight also becomes an issue, as higher output motors tend to weigh more, upsetting the boats' balance.

jky

[bicyclejuju1]

Ok thanks. If they say 15 I'll probably be ok w 20!

[Peter_C]

No 15hp is okay. If you want a bigger motor, get a bigger boat. Adding weight/power to the transom past what it was designed for may cause it to rip parts right off the boat (Especially on an older boat), and will cause water to come over the stern more.

Your gains for over powering the boat are outweighed by the possible consequences.