term used when steering won't return to straight?

what is the word/term i am looking for when you steer your boat in too tight of a circle while under heavy acceleration and the steering wheel is hard to turn back in the opposite direction (back to straight)? is it called chine lock? i remember mastercraft had an issue a few years back on one of their ski boats where when you went into a tight power-turn the steering would be difficult to return back to straight ahead.

cavitation?

i have heard the term cavitation all of my life and still am not sure what it means but that is not the word/term i am trying to think of. my mastercraft dealer used it one time when he was telling me of a boat mastercraft made a few years ago and how the steering would "lock-up on you in a tight power-turn". the driver would have to use both hands and significant strength to turn the wheel back to straight ahead. it was dangerous and for an inexperienced or weak-armed driver it could have been very dangerous. i think they may have come out with a new rudder to help correct the problem.

sounds like chine lock? my tige 21v RE used to have that problem all the time.. i outfitted it with a 4 switch Hippo ballast system available back then and anytime in a tight turn with passengers and sacs loaded, the chine would lock up and make correcting the steering very difficult, almost impossible, until i came off of power.. my buddy's first generation x star dealt with it quite a bit.. usually by just coming off throttle enough to subside thrust on face of hard-turned rudder will allow you to regain control.. of course, perfect pass back in those days would always compensate for loss in boat speed by accelerating while turning and sometimes made for some hairy situations when in tight quarters..

What makes the rudder hard to straighten if you are under power and in a very tight turn is the vortexes that the prop throws out past the rudder. In escense it loads pressure onto the rudder shaft so the steering is stiff. Come off throttle or hit reverse and it should stop.
Chine lock is where turning the rudder has little affect on the boats direction because one side, or the chine on that side has more influence than the rudder. You have to drop speed to let the boat achieve a more balanced attitude.
Cavitation is where an air pocket shows up in a fluid environment leaving a cavity. That's air on the back side of a prop that stops it from being effective so you don't get a push and the engine runs higher.

Art is right about chine lock and cavitation. For chine lock just back off the throttle. And yes a bigger/shape rudder does help. And for cavitation usually happends while turning, have a passenger move to the opposite side you are turning to help flatten the boat.

i just remembered part of the phrase after thinking about it again. i believe it has the word "hook" in it. something like "steering hook" or something like that.

IIRC "hook" is a feature of the hull. I believe it is a concave pocket in the the rear hull that is supposed to help with chine lock.

Its not chine lock or cavitation. When you turn a boat super hard (one way more than the other)cuz of torque steer, its is gonna be difficult to straighten back up. Your going against the flow. Maybe torque steer is the word your looking for.

F.U.B.A.R.

I also think it is chine lock.

Torque steer is what makes it easier to turn one side and harder the other.

On this case the issue is you have to pull real hard to straigten the wheel and stop turning.

Cavitation is when the water around the prop starts to bubble/boil because of a pressure differences around the propeller. As the prop spins the water moving past the blades is at a reduced pressure, once this pressure gets to a certain point the water turns to vapour. As the bubbles collapse they cause shockwaves which can sometimes strip the paint or even the material of which the prop is made from away.

I don't think this is what you're talking about though, not a lot to do with steering as far as I know.

Also as Art said the prop starts grabbing air (or vapour) instead of water so it "slips" in the water meaning you transfer less power and your motor has to do more work to make the same speed.

(Message edited by jtnz on May 12, 2008)