A Couple Things About Couplings

The general rule for fixing boats is 1. stop all leaks below the water line 2. stop all leaks above the water line 3. then make it smell nice and look pretty.

We ignored the order of these rules.

When Erin and I first bought s/v Social Security, the first thing we did was replace the cushions. What?! Yeah. Never mind the leaky ‘drip-less’ shaft seal, the mystery drips coming from the headliner or the smell. Yes, we got an excellent summer of sailing on the bay, but there were serious trade offs that made for anxiety filled nights coupled with a slight sinking feeling. Just go sailing, you can swim right?

Once on the hard for the winter, the first thing I did was address our ‘water’ problems, by replacing the shaft seal. The process went like this:

  1. Cut bronze shaft with hack saw and metal cutting blade.
  2. Cut bronze shaft again because you cut it in the wrong place and the ‘drip-less’ shaft seal rotor won’t come off.
  3. Have yourself a bit of a cry.
  4. Order a new shaft (for ’75 Sabre 28, 7/8 width  39-1/4 inches long), split coupling from Moyer Marine, traditional Buck Algonquin packing box and Western Pacific Trading GTU packing (5/16).
  5. Have the shaft machined to fit propeller.
  6. Use hacksaw on left arm to pay for step 4 and 5.
  7. Fit coupling to shaft so you have a press fit. This might require a bit of sanding with a high grit sandpaper. Mark places for fitting coupling to shaft because you wont be able to see how far to push the shaft into the coupling during the install in some cases.
  8. Drill set screw dimple in shaft (use cobalt self tapping drill bits). This is really important, if you don’t do this and slam into reverse in an emergency your shaft could spin out of the coupling.
  9. Assemble.
  10. Use 4 stainless clamps on the packing box hose.
  11. Install packing into packing box.
  12. Loosely bolt coupling to engine to hold it, but don’t tighten.
  13. Set shaft key so that it doesn’t extend outside of the coupling.
  14. Tighten 4 coupling bolts, tighten set screw and key screws.
  15. Install safety wire through the set screw and around the coupling.
  16. Install coupling to engine, I used a little Thread Lock.
  17. Align engine and shaft after boat has rested in the water for 3-4 months.

I love this shot because of the colors, I mean let’s just call it a ‘patina’ because that sounds better than dirt, rust and oil accumulation.

The business end of a Universal Atomic 4 (prior to install)

The Moyer Marine split coupling is a must have for this project. It will save a lot of hard work  and money if you should need to remove the shaft in the future.

For the Sabre 28, access is difficult to this part of the engine. There is access from the starboard sail locker, but there is a plywood panel in the way. I considered the lack of quick access not just undesirable, but a safety issue. If anything happens in this area, say to the hose, that 2 inch shaft log will let a lot of water in. In an emergency, you want to dive on this thing and plug that hole.

To remedy the lack of access, I cut an ‘arm port’ in the port quarter berth. There is a gas tank nearby, so it is critical that you know exactly what is behind anything that you are drilling or cutting. I cut this with hand tools. It is also worth noting that you can’t see the access port when the quarter berth cushion is laid down.

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