Friday, April 25, 2014

Somethin' was buggin' me

Somethin' in the back of my teenie tiny brain was buggin' me. I've been going over a list of stuff I have to get done in the near future and the rudder is one of those items. The rudder I have came with the kit that we bought. I don't know who built it or how it was built but the dimensions are 'close' to those on the plans.

It appears to be well constructed but the shaft is too long by almost a foot overall. I assume whoever built it didn't make it specifically for this boat. I've mocked up the skeg for the boat and used some advice from previous TW28 builders and need to make some modifications to the rudder before I can use it.

The first thing on the list is to have it shortened. Not an easy proposition since it's already built. It can't be put on a lathe to cut that way so it's pretty much an eyeball operation which worries me a bit. 5-1/2" have to come off the bottom of the rudder and 6-1/2" off the top.

Second is the shaft has to be cut just above the top of the rudder blade. This is to allow two stainless steel flanges to be machined and welded on. These flanges will allow the rudder to be unbolted and removed without having to dig a huge hole beneath the boat or have a crane brought in to lift the boat.

I got these two SS flanges off of eBay pretty cheap. They're used in piping in the nuclear reactor industry! :-) So quality isn't an issue. They will require a little machine work before they can be welded on.

Next issue is size. The rudder is just a bit too big and there won't be any room between the bottom of the hull and the top of the rudder for the SS flanges. I don't know how the rudder was built so I had to cut into it. In order for the flange idea to work it'll need more room.

I removed about an inch or so from the top of the rudder. Looks like high density closed cell foam on the inside and a couple of layers of glass on the outside. I drilled down into the foam and hadn't hit the first flange so we can easily take off more material if needed.

Even modifying the shaft as radically as this there still won't be much room and especially on the bottom where the rudder bearing will mount.

I need at least 1-1/2" for the skeg channel and the bearing. This meant  I had to leave this end a little longer than I would have liked. I'll haul the whole thing off to the Machine ship on Tuesday to see if it can even be done. If not I have another 1-1/4" shaft that I can start over with.


PS. Yeah! No sanding today! Wohoo!