August 30, 2010

During the week I tried a little experiment to replace the leaking gaskets on the old Ta Chiao bronze ports I bought on ebay. The ports are probably 25-35 years old and the old dried up and brittle gaskets are now pure unobtainium, so I had to improvise. After removing the old gasket, I tried filling up the groove with silicone, letting it cure and then trimming it. The resulting gasket was pretty uneven, so I wasn't shocked when it leaked like a sieve when I tested it. To paraphrase Thomas Edison, I succeeded in finding a new way in which a gasket won't work. Hopefully I'll be able to find suitable material at McMaster-Carr. Over the weekend I started tackling the leaking hatches. On Saturday, I removed the forward hatch, a Bomar, to take it home and clean it up prior to rebedding it. Luckily it came off the teak base pretty easily. Thank goodness it wasn't adhered with 5200! Once it was removed, it was clear that the previous efforts to stop the leaks by slopping caulk over the teak joints were misguided as well as crude. The fiberglass molding of the cabin top included a rim and base upon which the teak hatch base was mounted. Any leakage in the teak base would drain harmlessly off the cabin top. That was actually reassuring. The leaks would have to be either around the plexiglass in the hatch itself (bad), a bad hatch gasket or faulty bedding of the hatch. I was going to have to rebed the hatch anyway, and planned to replace the hatch gasket as well. With the hatch removed, I ground off the excess caulk from the teak base and sanded it until it was ready for some epoxy. I thought sealing it with epoxy would help stabilize it as well as get it ready for a couple of coats of Cetol or varnish. I brought the hatch home that evening to leak test it and grind off the gunk around the mounting flange. I took a chance by replacing the old dried out gasket with some cheap car door gasket material. It didn't fit properly and testing confirmed it leaked badly. So now I'll have to order the right stuff at twice the price...no big deal. The good news from the testing was that there was no leakage in the plexiglass-to-frame joint on the hatch.

Sunday I remounted the hatch using 3/8 round butyl tape. It was a pretty messy job despite my attempts to be neat and careful. Butyl is like a cross between tar and chewing gum. The stuff sticks to everything, and once it pulls the surface oil off your skin, it sticks to your fingers, making it hard to mold and manipulate without creating a scene worthy of Laurel and Hardy. And of course it would just stick to and pull apart disposable gloves. You can just make out the black butyl around the flange of the inverted hatch in the photo below: Nonetheless, in the end, I got the hatch mounted neatly, and, because the butyl stays sticky and flexible indefinitely, the bedding should be leak-free for as long as I own Circadian. Later I will need to finish off the edge with some 3M 101 or Sikaflex 291 and put some varnish on the teak base to protect the epoxy from UV damage. When it's eventually all done, of course I'll have to test it.

The rest of the day was spent removing the leaky plexiglass window in the top of the doghouse. While not as critical as the cabin leaks, I want the doghouse dry to protect my instruments, my paper charts , my crew and myself. I understood why the P.O. just covered it with a sheet of plastic when I started wrestling with the 36 bedded bolts that secured the window. (Some of the bolts I removed can be seen in the photo below.) I was eventually able to get all but five out myself. I had to enlist the help of a dockmate with those since I just could not manage to hold the machine screw outside on top while cranking on the nut below at the same time. Being two different places at the same time is a tough one! Again I was lucky in that the window was bedded with a non-adhesive compound and came up pretty easily. Although crazed, the window was 3/8 inch thick...a good thing! At home I'll need to clean the old bedding off the aluminum frame, mark the frame parts for easy reassembly, and unscrew the frame from the plexiglass. Then I'll get replacement plex at TAP Plastics, put it back together and remount it.

By this time I was pretty beat, so it was all I could do to make some measurements for the new bronze ports and clean up the mess before wearily driving home.