When I was working with the straps and positioning them, one thing I noticed is that there will only be about 1-1/2" of projection in front of the pivot point. The standard rudder leading edge is well back from the actual pivot point. So part of the 3" of added width is used just getting to the pivot point. In my research before building thing thing all I found were owners adding the ~ 3" amount. I would be curious to know the effects of a more modest add of the 1-1/2" would be. My goal has been to make this helm be easily manageable by my wife, so once we get on the water this summer I will advise her report.
One of the minor surprises on this project is that the original and this new NACA0012 shape are modestly different for the given chord width. One thing this difference does is make the straps that attach to the rudder happen at a slightly different part of the chord, essentially further aft. So while max section thickness is the same between the two rudders the section thickness where the straps end is less than in the original. So I have had to build up some section thickness and maintain parallel surfaces. This has taken a bit of sorting, but I think I have it now. I also have to compensate for the planned thickness of the glass, so a bit more head scratching and hopefully I will get it right.
I am planning to use one layer of 29 oz. biaxial and two layers 10 oz. cloth, not counting areas that I have already glassed over like the bottom edge and the entire top of the rudder. I think this is way more than needed for strength considering the oak core, but probably adequate for moisture intrusion. I am planning to vacuum bag this thing and that will be a first for me, so hopefully I won't end up running out of the shop screaming.
One problem I could use some help with is figuring out a method to drill the holes for these straps once I get to that point. These straps are not perfectly square to the world in the first place and trying to drill perfectly through to opposite side to hit the opposing hole accurately is going to be tricky. One idea I have is to drill a 3/16ths hole all the way through to see the first shot lines up ok, then advance to larger diameters and more or less mill the holes as needed to get a final result. If someone has a better idea I would love to hear it.
I have been doing video for this rudder build as well and once I have a minute to get through editing I will post that. This will be a multi part video that shows the details as I sorted them out, and a bunch of sorting I have done.
