Posted By: Coastie
Rudder(s) - 10/26/17 04:34 PM
One of the more fun projects I'm doing this winter is replacing the rudder. I may actually build two, a copy of the OD shape and a second that is more balanced with at least 2" in front of the pivot point. I have a couple of questions: First for anyone that has the wider balanced rudder, what is the best new width? I see an old post on Sailing Anarchy where it was suggested to add 60 mm (2.36") and that seems like a reasonable amount. Second, I have lots of nice quartersawn oak around the shop and it would be easy to use it for the core. Since it has substantial structural strength itself compared to the old balsa core I could reduce the section thickness of the covering glass, or I could go get some spruce which would be a dramatically lighter core and then just use the same glass section thickness as the old rudder. My planned fabrication process requires the use of solid wood rather than balsa or other core materials.
No matter what I do the new rudders will be dramatically stronger than when they were new, since I will be using cloth rather than all the chop strand used in the original rudder. The glass section thickness covering on my old rudder is about 1/4" albeit with a substantial reduction in that actual section thickness now with the thousands of serious blisters all over it (and it didn't fail in some pretty hard use by the PO). A curious side note here, the blistering on the rudder in terms of the density of the blisters is probably 10 times greater than what I was faced with on the hull. I assume these rudders used the same polyester resin that was used on the hull, for sure the same chop strand mat, why would the rudder be so much worse for osmosis?
Once I sort out a couple of these issues I will build these rudder(s) and I will show how I went about it.
No matter what I do the new rudders will be dramatically stronger than when they were new, since I will be using cloth rather than all the chop strand used in the original rudder. The glass section thickness covering on my old rudder is about 1/4" albeit with a substantial reduction in that actual section thickness now with the thousands of serious blisters all over it (and it didn't fail in some pretty hard use by the PO). A curious side note here, the blistering on the rudder in terms of the density of the blisters is probably 10 times greater than what I was faced with on the hull. I assume these rudders used the same polyester resin that was used on the hull, for sure the same chop strand mat, why would the rudder be so much worse for osmosis?
Once I sort out a couple of these issues I will build these rudder(s) and I will show how I went about it.