Windlass replacement

One of the things we knew we would have to fix on the boat when we bought it was the windlass. Despite visible corrosion, the windlass worked at the survey (done in September) so we assumed we would not have to repair it right away. Fast forward to the following spring, and now the corrosion had gotten worse, and the motor was seized. You can see from the photo below, that the motor basically had a rust “tumor” growing out of the bottom of it.

Additional examination of the windlass indicated that we would have to overhaul parts of the gypsy mechanism in addition to replacing the motor. There were also signs of corrosion on the gearcase, and it was 20 years old. After pricing out the various repair parts, it turned out that it was not that much more expensive to simply replace the whole unit. Doing this would give us a brand-new unit for a similar price, which would head-off any future repairs of the old one.

As with other repairs of this type, I chose the same brand of windlass to make for an easier replacement (holes match up, sizes similar etc). Happily, Lewmar, which made the original unit, sells new models that match the old ones. Using the model number of our existing unit, I was able to find an exact match (same size and mounting holes) which would simplify the install.

Removing the old unit was not difficult. First, I had to secure the anchor, and then detach the chain from the anchor. The chain was then run into the locker so the windlass could be removed. Luckily the fasteners had not corroded and so I did not have to cut anything. Took a little wiggling to get the pieces apart, but overall, not difficult.

However, this operation revealed two nasty surprises. First, the deck that the windlass was mounted to was not well reinforced (production boat sickness). It turned out that the studs supplied with the new windlass were sized for a thicker deck, and would not work with the Mainship deck thickness (thinness) where the old windlass was mounted. Secondly, although the holes all lined up, the new windlass required a slightly larger hole for the gearcase shaft.

Enlarging small round holes requires some kind of guide to centre the drill bit. Given the hole size, I needed to use a hole saw, which would require some way to guide the pilot bit. The way I did this was to build a backer-plate for the windlass out of inch thick starboard lumber. I did this in my workshop so that all the holes would line up exactly, and made sure the windlass fit the backer plate exactly. I then made another template from ¼” plywood. In this template, I drilled the 4 holes for the windlass studs, and drilled a small hole for the hole-saw pilot in the centre of the larger holes for the chain and gear shaft.

On the boat, I mounted the starboard backer-plate temporarily on the deck and the plywood template under the deck, using bolts through the stud holes (bolts same size as the holes) to line everything up exactly with existing holes. I could then use my hole saw to enlarge the gearcase hole, as the backer and template would guide the holesaw exactly in the centre of the existing hole. While I was at it, I also tweaked the hawse hole for the chain.

Once the holes were drilled, I removed the backer and template, and mounted the windlass placing the backer-plate underneath the deck. This reinforced the deck, and now the studs could easily be attached through the thicker deck. 

Once this was done, it was a simple job to attach the motor. Since the windlass model matched the old one, everything including the wires lined up exactly. The only wiring modification I had to do was to replace a corroded connector. Finally, the gypsy was assembled, and the chain was re-attached to the anchor.

Windlass worked perfectly.

The windlass came with a solenoid controller and switches, which I kept as spare parts (they were the same as the original ones, which were still in good shape). The whole project took about a day in total, not counting travel time to and from my workshop and the boat.