Thursday, September 08, 2011

Strut Rudder results

I am quite happy with the improvement in steering provided by the strut rudder. It seems to be far more effective than the dipping rudders in turning the boat. When both a dipping rudder and the strut rudder are used to turn in the desired direction the boat is almost able to be controlled to a reasonable extent. Of course, it is nowhere near as maneuverable as the Cadence and far from the maneuverability of the Escapade, both of which have the advantage of propeller thrust against the rudder. Still, it is an excellent improvement.

I found that the nylon tie was getting abraded by the aluminum on both the rudder and the strut bearing bracket. This was due to the fairly sharp edges on both. I have since rounded the edges of the hole in the rudder through which the nylon tie goes. The strut bearing bracket will have a second nylon tie over which the supporting nylon tie will nest. This way the inner tie can be tightly held to the aluminum bracket and provide a smoother bearing surface for the tie under tension holding the prop shaft to the rudder.

+/- 20 degrees appears to be all that is needed. In fact, turning the rudder slightly less than 20 degrees significantly reduces the aeration of the propeller.

Cruising speed seems to be either unaffected or possibly very slightly slower. However, not having to adjust course by dipping the rudder should make overall speed better.

Will I remove the dipping rudders? Right now I'm not sure. There are times when having the extra rudders for a somewhat tighter turn makes life easier. I also have to see if the nylon ties have an adequate lifespan to place all my trust in the strut rudder. Otherwise, an alternate mechanism or material will have to be used.

I still have to replace the prop shaft with one that is not bent. That project is nearly done as the tubing and rod were cut to proper length and bonded last night with fillet material and cloth. After it has set for two days I'll drill a hole through the diameter of the tubing and insert a stainless pin to make doubly certain they stay together.

I expect cruising speed to be a little higher and be able to maintain it for a longer time.

Work has begun on modifying the dipping rudders to have a 20 to 25 degree angle rather than the 40 degree angle they currently have. This involves cutting the fillet and glass securing the wood pieces to the fiberglass tubing and re-adhering them at the proper angle. This should be done in a week or three.

Meanwhile, I'll give it a try with just the strut rudder for the next race.

Labels: ,

0 Comments:

Post a Comment

<< Home