Turning

[cyberhoops]

I have a question to see if I am on the right track here - or get ideas on what I might do to improve the turn radius of my 1/10th scale boat.

The boat is a model of the 1985 Miss 7-11, but pretty much exactly following the Newton Marine plans. It seems to run fine in a straight line, but the turn radius is bad... like lane 10 turning is the best it can do right now.

I already increased the rudder throw as much as I could with no real change in the turn radius.

I was thinking that moving the turn fin further aft might have an impact. Right now it is pretty vertical and tight to the rear of the sponson. It seems to me that if a turn fin was set very far forward - turning would be poor. On the other hand a turn fin back by the transom would make the boat very twitchy in a turn. If that is true, then moving my turn fin further aft might improve my turning circle.

Any thoughts would be appreciated.

[ED66677]

have tried a longer/wider rudder blade?

[Fluid]

Placing the turn fin ahead of the CG (moving it forward) will help turning while moving it back can hurt. I suspect that both your rudder and turn fin are too small for the hull and the speeds it runs. You should not need full rudder to make a lane 10 turn, that's a radius of over 50 feet. Keep the turn fin where it is and put on larger rudder and fin blades.


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[j.m.]

The rudder probably just isn't grabbing enough water. The turn fin and rudder should probably be deeper in the water. (Longer blade) (Fluid always knows what hes talking about)

Jon