Wednesday, April 16, 2014

Twister Refit

A wise man once said, "Perfect is the enemy of good." 

Blisters getting epoxy treatment
 The refit (that's boat-speak for renovation or refurbish(ment?)) is in full swing. I started with a week’s worth of sanding, and several blisters (aka osmotic blisters which result when the outer layer of the hull is not totally waterproof and acts like a semipermeable membrane…) were ground out then filled with epoxy.
  I had planned to redo the whole gelcoat, but several layers of old hard antifouling paint proved tougher than anticipated, so below the waterline only the blisters and some spots on the bottom of the keel (where the gel coat had been completely shaved off due to a few groundings over the last 35000 miles) got the epoxy treatment. Above the waterline, the worn, crazed, and chalky gelcoat was sanded then treated to two coats of epoxy barrier coat (epoxy diluted with solvent and with white pigment added) followed by two coats of white two-part polyurethane paint. 
Looking better
Below the waterline, the hull got one coat of red ablating (gradually wears off as you sail) antifouling paint (two coats near the waterline. The waterline was also moved up ca 5 cm as the old bootstripe was sometimes underwater when Twister was fully laden. 

New antifouling paint below waterline
Polyurethane paint above waterline
The rudder had a rather long crack along the wooden part that extends above the waterline to the tiller. I cut a v-shaped trough along the entire crack with an angle grinder and after letting it dry about a week laid up a couple of layers of fiber glass and epoxy resin. It looks pretty solid now. Below the waterline I discovered the rudder had about a liter of water inside it (not good), when I attempted to repair a blister. I drilled a big hole all the way through to drain it and let it dry out a bit (the inside is polyurethane foam like a surfboard). The next step is filling the hole with polyurethane foam and then closing the holes with fiberglass/epoxy. Then the rudder gets a couple of coats of epoxy barrier coat, followed by antifoul below the waterline and polyuerthane above the waterline just like the rest of the hull. 


I abandoned (postponed) the plan of replacing the through-hull fittings (where water comes in or out of the hull for engine cooling, toilet, sink, bilge pump, etc.), but my dream of replacing the cutless bearing was given new hope when I was able to get the prop shaft out of the hull (made easier by the fact that I had already removed the rudder). The old cutless bearing was quite worn and in an asymmetrical fashion, causing a lot of play in the prop shaft. 
Old cutless bearing
New cutless bearing
Some internet searching revealed that the usual method for removing the cutless bearing (which is more like a bushing – no moving parts. It consists of a bronze tube lined with a semi-flexible polymer with about ten channels running the length of the tube, allowing water to lubricate the prop shaft up to the stuffing box) is sawing it in half from the inside, collapsing the tube. In my case, the thing came loose after one side had been cut.

Fortunately the boatyard a 1-minute bike ride away had the right-sized cutless bearing in stock. While the prop shaft was out, I decided to replace heavy-duty hose that connects the stern tube to the stuffing box (aka stuffing gland. It is not a box or in any way rectangular) as well as doing some work on the stuffing box (the locking nut had been stuck for a long time, making adjustment of the stuffing box difficult. Due to access problems, I had thought this job impossible without removing the engine, but only minor contorting was necessary to remove the four hose clamps and pull the hose off the lip on the inside end of the stern tube (stern tube is just the hole in the hull that the cutless bearing sits in.

The stern tube has a lip on the inside end where a heavy-duty hose connects it to the stuffing box (which is the seal that keeps the water in the stern tube out of the boat, or at least mostly keeps it out).
Old stuffing

new hose and refurbished stuffing box

New stuffing

If anyone is still reading at this point...who wants to sail from Norway to California with me via The Beagle Channel or The Northwest Passage?
OK, more refit:   The six chain plates where the shrouds attach have been rebedded with butyl tape instead of polyurethane or polysulfide caulk. I have big hopes for this butyl tape stuff. All the other deck hardware (genoa car tracks, stanchions, windlass, handrails, etc) will also be rebedded using butyl tape. New wiring,  Bla bla bla...

Twister goes back in the water April 26. Hopefully the mast will be up soon thereafter. More photos from refit. 


  1. Excited to see Twister (and you) prepping for a new adventure. Do you have an estimated departure date? I'm still game, but still not sure I'll have the wherewithal.

  2. I came across your blog and had to read from the beginning. Very impressive trip!