Changing a boat's characteristics

[Stumble]

Strudders,

I am coming late to the party, but the first thing that crossed my mind was to modify the rudder. There are really three ways to do so, they all have advantages and since there is little downside to any of them you might want to consider all of them at the same time.

1) Reduce the clearence between the top of the rudder and the hull to the minimum possible. This reduces the effects of arration when the rudder first starts to exit the water, and increases its bite in these circumstances.

2) Increase the draft of the rudder. Typically in rounding up situations it isn't necessarily caused by a lack of rudder area, but that too much of the rudder by percentage has released from the water. In this situation increasing the depth does a better job of fixing the problem than increasing general rsuface area.

3) Increasing the overall size of the rudder. See 2 for my thoughts.


As for the 'bouncing' I am not sure what motion specifically you are refering to here, but it might actually be that you have removed too much weight out of the ends of the boat, and too much from up high. I know it sounds weird since most sailors fight to get weight low and on top of the keel, but pushing weight high actually slows down the rolling period of the boat (making it less responsive... bad for racing good for reducing jarring motions). Try shifting some gear higher up on the boat and towards the ends, and see if this doesn't help reduce the bouncing motion you were talking about.

There are ways to modify the shape of the keel without changing the keel attachment points. Mostly by designing a bulb forward or backward keel. However these impart a large amount of twisting motion on the hull and may require reinfrocing. Which when combined with the cost of a new keel can be pretty expensive.

I would also recommend inviting a local sailmaker out with you to experience what you are describing. He may be able to suggest specific trim options or sail modifications that would help to reduce this as a problem.