a new idea

[^] well people there seems to be an idea that seems worth while to some members. has anybody ever thought of a rc sailboat with a retractable centerboard? this could be like a laser. and would be fast down wind.
see what you think
long live the cup and cris dickson

Ok, Where is the righting moment coming from?

Luff 'em & leave 'em.

Cougar, It’s already been done! You have even seen the boat it was fitted on but you did not know the keel was retractable. :slight_smile:

We did it years ago with a worm gear drive and a toothed bar out of a typewriter.
The bar ran along the back edge of the keel. Total lift was about 9 inches.
It worked great right up to the point where you forget to put it back down at the leeward mark and your boat spends the next 30 second trying to right itself, and drifting further downwind with it’s bottom to the breeze, and the sails in the water.
The extra weight and complexity upwind will quickly lose what you gain in downwind performance.
Keel fin drag is less than 1% of the total drag on a well set-up boat.
The other problem is with a boat like an IOM or 10R,the keel weight (pendulum) is required to keep the boat from going bow down in a puff.
The other problem is where do you put a 9? long keel when you lift it up through the deck? The main boom is right there and gybing is impossible with the fin sticking up in the air.

Neat idea, but way too small an effect to warrant the design and complexity.

Peter R.

Visit www.climatemodels.com

Peter: Thank you for the great response. Its this kind of reasoned discussion based on real world experience that is truly valueable.

Fact is, r/c boats about forty years ago used non-retracting, lead “fins” without bulbs. To get sufficient weight in them the fins were very, very thick and compared to today’s fin/bulb keels were very, very slow.