vibration during turns

I'm new to the inboard ski boats. We bought a '78 Martinique 351W Commander toward the end of last summer. I notice when my skier falls and I turn around at speed I feel a lot of vibration. Is this normal? Does it mean I need a shaft bushing? ...or a rudder bushing? ...or should I just get used to it?

Nauti Girl,

You may be experiencing propeller cavitation. Are you turning around the same direction each time? Try turning the other direction and see if the vibration changes.   My '89 Nautique sensitive to direction in a sharp turn.

Jeff

One reason for vibration in that particular situation is that the prop sits back to far from the strut and causes vibratio ,among others. Your condition could be other reasons, not knowing your boat condition. However the prop only needs to be the width of a propeller puller 1/4 inch from the back of the strut. However in 1997 they changed amd put the props about 5/8 inch from the strut. A comprise fron a 1/4 inch. This I know because it my suggestion.

When they changed the prop position the vibrations went away, 1997 for CC. Your experience is because your boat turns the opposite rotation to CC. CC is the only boat in the industry today that turn right hand propellers all the rest are left hand.If you look at all the older boats prior 1997 you will see that the props are 2-4 inches away from the strut.Most all the boat Ski tow boats except maybe Sanger, MB Mike Brendella boats didn't experience this because they both were high performance builders and drivers. I know this because I drove with and against them. The farther the prop away from the rudder the less force against it and makes it easier to steer, also helps to put bow up. IO are completely different situation.

SS-201,

Thanks for the info. When you talk about the distance from the strut to the prop, is that as measured from the trailing edge of the strut body to the forward most portion of the propellor blade, or is it from the strut bushing to the prop hub?

Also, my boat is a 1989 Ski Nautique. I think you had the impression is was not a Correct Craft.

Jeff

Dollars to donuts what your experiencing is cavitation. When you turn at skiing RPM's (or higher....great feeling) the forward speed is reduced but the prop is still spinning at high RPM's and pulling water through it which increases cavitation AND the prop is also "sliding" sideways due to the turn which also increases the risk of cavitating the prop.

The prop is also "sideloaded" slightly from the turn and can induce flex into the boat and any misalignment is magnified (make sure you do Tryans post for things to check) it could be both cavitation and misalignments.

Nauti girl- when my cuda had the wrong sized prop (bought it like this) it would make a ton of noise when turning sharp.This was magnigied when pulling a tube-er.With the correct size and pitch prop, the noise and virbration is drastically reduced.Make sure your prop is sized and pitched correctly for your model.

My 66 came with a 14X11 I had an amazing amount of vibration/Cavitation. I replaced it with a 13X13 and 90% of the vibration went away. I now find that a 12.5X 13 was original Equip.