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Florida flat-lander refitting an Alberg 30, hull #329, for an eventual circumnavigation of the globe and the journey of a lifetime before I get too old!

Sunday, October 16, 2011

Thiokol - Satan's caulking

Friday was spent removing the stern tube and the thiokol that had a titan's grip on it. Thiokol is a grey, hard yet rubbery substance that is also sticky kinda. It is unlike anything I have ever worked with and I hope this is the last time I ever do.

I started by putting a socket wrench on the one remaining bolt holding the stern tube to the deadwood. With about two pounds of pressure the very top portion of the head of the bolt disintegrated. Out comes the Dremel Tool to cut off the bolt which went smoothly but not the way I wanted it to do this. Once it was ground down and looked like the other broken bolt I tried to pry the stern tube out of its hole. I could get it to move about a 1/4" and when I let it go it would snap back in as if it were held in by something rubbery. I knew then that I was going to have to remove the rubbery devil's caulk.

I spent the rest of the day, about five hours, laying on my stomach on this board scraping, cutting and cursing.

This is the point at which I was able to pull the stern tube out. Four inches of thiokol removed.

And the stern tube. You can see that is had a black rubber gasket around it aft end which reacted with the thiokol. It also had a large amount of what I think was burnt oil which I found to surprising.

With the tube out I returned to my oh so comfortable board to remove the rest of the thiokol. After a couple of hours fighting this stuff I decided to just take out what I needed to in order to make future stern tube repairs. It is not a perfect job but by this time my hands were killing me. I may finish talking the rest out later but this is what it looks like now.

I have all winter so maybe I will find a reason to punish myself and get back in there and get the rest out.


  1. So, I find myself in the midst of the stern tube issue. What began as a plan to replace the cutless bearing turned into loosening the cutless bearing housing and now, apparently, I'll be pulling the stern tube as well. I don't seem to have the mass of caulking that you do, and yet I'm having a tough time getting the stern tube and cutless housing off. I read that the cutless bearing housing unscrews from the stern tube. Is that accurate? What are your plans for putting that area back together? Will you use the original equipment?

  2. On my boat anyway, the stern tube and housing are one solid piece of cast bronze. I have not seen any evidence that one unscrews from the other. I also did not look that closely either since I knew I was replacing with something else. I do know this: the housing/tube would not budge until I removed the thiokol and then it was easy. BTW the thiokol was painted over and looked like glass.

    I will replace with a G10 FG tube and stuffing box assembly that I bought from Spartan Marine.

  3. I'll have to poke around some more to see if there's still caulking. I am able to spin the cutless housing (with some force), but it's not free enough to remove.

    Where are you sourcing your G10 tube, and what are the dimensions you'll be using? Which Spartan stuffing box did you get?

  4. Ok, got the cutless bearing housing off. It unscrews - just as the Alberg 30 site says it should. It appears that my stern tube might have partially "unscrewed" with the housing, though. If so, I'm sure it compromised the seal through the deadwood.

    You didn't chuck your old housing and stern tube, did you? If not, interested in parting with it? I had to drill one of the bearing set screws out and it appears a PO cut the aft end of the housing for some reason.

    Happy Fourth, by the way!

  5. I would be happy to send it to you. I do need to do something with it first though. I have to put it back in temporarily and run a string so I can mark the angle for posterity. I am doing a repower which requires new beds. The angle needs to be 90° to the outside face of the deadwood and the old log is the easiest way to get it. I will do that in the next few days.

  6. Almost forgot, I answered your other question with a new post!

  7. Cool! I will be doing essentially the same thing since the PO put together a rather awkward engine "bed" based upon the old A4 mounts. Maybe I'll actually update my blog with some pictures and description. By the way, my email is ariel dot cd36 at gmail dot com. It might be easier to keep up communication that way.