a Question of Balance

[Patrik111]

Hello All,
Last year I built a 14ft performance dinghy. After last summer I decided to highten the deck to get more boyancy and less water in the cockpit when capsizing ( frequently occuring ). This modification has resulted in me having to move the mast step aft about 5 cm. The mast will also have a possibility to be raked more in the new configuration. The centerboard has a cord of 32cm and the distance rudder-CB is about 220cm (leading edge-leading edge.). The boat carries about 160sqft sail upwind and an additional 225 downwind.

The question is how much this movement of the center of effort of the sailplan will affect the balance of the boat. In the old configuration there was no weather helm and no lee helm.

Greatful for input in this matter

Patrik Elfving

[John E Hardiman]

If you only moved the mast 5 cm (2") aft, rake the mast forward to get the center back to where it was.

A bigger question would be how much you changed the lateral plane by sinking the hull down forward with the added weight of the higher bow.

[Aramas]

If there was no weather helm before the mods, then the rudder was not producing lift, which is a bad thingTM. I'd just rig it as is with the new mast location, and see how it goes. A bit of weather helm is mandatory. Without it the rudder is producing drag with no lift. Any foil needs to be operating at an angle of attack in order to produce lift. It sounds like the mast needed to be raked aft before the mods.

[brian.cunningham]

Here's a good page on the subject
Balancing the Rig (http://www.paddlin.com/fivelakes/balrig.html)