Windlass, chain locker & anchor

A $150 windlass

I found a pretty good deal: the bones of a Lewmar Pro 700 windlass for $150. I replaced all the bearings and seals, and made a new motor cover, because the original had been destroyed by corrosion. It looks like the previous owner sealed the drain hole, and the windlass filled halfway with salt water. I also replaced the brush springs and the compound gear, which was in very bad shape, then polished the body to a mirror and passivated it.

Here's the motor at the start: the mounting ears destroyed, the brush springs rotted away, the bearings rattling like crazy, and still the motor worked. I cut the new cover on my home-made plywood CNC. Then the motor went back in place. And then, two years later, I finally got to installing it.

The original "bow roller" doesn't fit ANY anchor. On a 34-foot boat it looks more like a joke. At best you could run a rope over it for a lunch hook. 5/16 chain doesn't fit at all. So I cut off one plate on the starboard side to install a real roller that takes my 25 lb CQR and 5/16 chain. Here's the side plate off and the roller dry-fitted; it needs a spacer plate at the back.

In June 2024, right after the deck was painted, I cut out the starboard roller plate, very roughly dry-fitted the new chain roller, and measured the chain locker.

The windlass mount

I modeled the chain path to put the windlass in the right place. Here's the very first mount prototype. The second dry fit showed that I needed to move the windlass 2 inches to port.

Then came the first real version of the mounting plate. The dry fit showed that the windlass must move 25 mm toward port to line up with the chain. I also dropped the front piece and kept just the "bridge".

After a lot of thinking, I decided to bolt the windlass mount to the chain locker. My reasoning: the load can't exceed the windlass's max pull times a safety factor, say 2. The pull is 300 kg, so under 600 kg on the mount. Six 5/16 bolts would be total overkill, but the locker is only 5–6 mm of fiberglass, so the load has to be spread. The bolts only stop the mount from sliding up; the sideways load is taken by the locker's wedge shape. But the chain comes in about 4 inches above the mount, so it tries to lift the back of the plate, maybe with up to half of the main force. With two bolts per side, no bolt sees more than 300 kg of shear. And fiberglass laminate is good for 1,000–2,500 MPa; a 5/16 bolt hole in 5 mm gives about 0.00004 m², so even at 1,000 MPa that's about 40 kN, about 4 metric tons per bolt. We should be good.

So I used the chain locker itself as a mold for the mounting plates, so they match the walls exactly and spread the load evenly. Masking tape, PVA mold release, then two layers of 1708 on the walls and all the way up to the top of the mount. In real life only the corners show. Here's the bottom view during the first layup. Then out of the "mold": now I had a perfectly matched base to build on. The cutout on one side is for the black water tank vent.

Meanwhile, I wanted to rebuild the encapsulated fuel tank, which could take weeks, but I still wanted to sail. So I put a 2-gallon "spare" tank in the engine compartment. It's the one-time-use type, but I hope it survives a few dockings. Not bad as a short-term solution.

Then back to the garage: I cut off the extra, sanded, and started building up the inside. I cut a 5 mm G10 "interface plate" on the CNC with the exact windlass bolt pattern. It saves time, guarantees a flat surface under the windlass, and lifts it a little, so I can service the gears and motor without taking the windlass off the deck. The plate was laminated on with thickened epoxy and filled around with epoxy filler.

Then inside fillets, and four more layers of 1708 from below to the mounting plates. The brown color is the old hardener from a metal can again. I trimmed the leftovers with a knife when the resin had kicked enough to hold its shape but was still soft.

Since I built it from the inside out without a mold, the outside needed fairing compound (TotalBoat epoxy fairing) and sanding to get flat. Then sanding again, two coats of primer and one of Interlux Perfection, the same as the whole deck. And we have an almost perfect part, almost ready to install. Here's the windlass dry-fitted on the finished mount, and the mount dry-fitted on the boat.

For now I'll keep it removable, on six 5/16 bolts to the locker walls. The main reason: access to the nuts under the deck for the bow chainplate and the pulpit. You can see the small plate on the front of the locker. If the mount were permanent, that access would be very hard.

A deeper chain locker

At first I planned 60 feet of chain and the rest rope. But when I went shopping, 90 feet (the maker's full bucket) was actually cheaper than 60 feet cut to order. So 90 feet it is: now I can be on all-chain rode in up to 10 feet of water, which sounds cool.

But a windlass needs at least 10 inches of free drop under the gypsy, and my locker was maybe 12 inches deep. Not enough. And I'm a lazy guy: I'd rather spend a week building a deep box than toss chain around by hand every time. There were two options.

Option 1: cut through the existing locker, build a watertight bulkhead and use the whole bow as a chain locker. Pros: a really big locker, the chain kept low, and a "crash" compartment if I hit something and hole the bow. Cons: it can't drain by itself, so it needs another pump or a drain into the main bilge, which I don't like. It's big, 30–50 gallons or more, and a wave over the bow could fill it in seconds, especially if the lid ever opened. And I'd want to reinforce the hull sides there: 6–8 mm of extra glass, laid almost upside down in a tight space. Plus that makes a hard spot in the hull, which can bring its own problems.

Option 2: cut a hole and build a 6–8 gallon bucket big enough for all the chain. Pros: it can be removable for access to the bow, a small volume can't hold much water even when full, it's much easier to build, it gets a nice inside surface if built on a mold, the hull isn't compromised, and the V-berth bow door stays. Cons: it's smaller, so less chain, the weight sits higher, it's hard to measure a box that fits well, and the old drain hole must be closed and a new thru-hull made.

The decision: option 2, a self-draining box hanging from the deck, as removable as possible, or at least easy to cut out. And the existing wood bulkhead gets glassed watertight up to the waterline, with the door staying, mostly for some protection if the bow gets holed.

I cut the bottom out of the original locker, made a wood-strip template for the box, and, using the old locker as a mold, a template of the "interface" with the existing walls. To make the box removable, it needs a tight interface to the existing walls. Then I checked the depth of the new locker and made a template for cutting the original locker lid.

The plywood box is a mold, not a core. An inside mold means no glassing inside the box, and a nice surface. It should be 10 mm smaller than the space, and 10 mm shims on the sides stand in for the future fiberglass. It fits well. The front and back interface plates went on in place to set the mold's position.

I cut off the extra plywood "ears", put thickened epoxy fillets inside, routed and sanded all the corners round, coated it with two layers of epoxy and patched the corners with epoxy fairing filler. Two days later it was sanded glossy smooth and ready for laminating. At the last moment I remembered that the bottom needs a dip for the drain. It's not in the pictures, sorry. The 3D model, a PDF drawing and DXF files for the mold panels are in my online folder, if you want to build the same.

Three layers of CSM went on the mold, and then the mold came out. Yes, I used mold release, and yes, I tried to be careful, but in the end the best way out was to break the front and back, squeeze it and pull. It was a one-time mold anyway. Still to add: at least three layers of 1708 overall and five on the interface, for about 4–5 mm on the sides and 6–8 mm at the interface and corners.

This is what came out of the mold. No gelcoat: it's inside and won't see the sun, but I want it to look good, so the smooth surface gets bilge paint. Then I bonded the interface to the box with thickened epoxy in four spots, in the boat, and took them home together to fill the gap properly. The corners only look like huge bubbles; they're sanded.

The original drain was too high to keep, so it had to be closed. The hull there is about 6 mm, so a 1:12 bevel is 72 mm around. Seven layers of 1708, small to large. The first five were done, two were left. The patch from inside is done; the fairing outside comes next weekend.

The box was ready, and the opening was ready. A new thru-hull went in on a 5 mm FR4 backing plate set in thickened epoxy. I know that wire splice looks wrong; it'll be fixed.

The box went in, "kind of" removable: on 3M 4000UV and nine 1/4-inch bolts. It sits on a cone shape, so the bolts just hold it in place. Even without them I could stand in it. The sealant fills the gap between the old surface and the box. Later, a couple of layers of glass cloth around it, to be 100% sealed and level.

The drain is thick-wall clear 3/4-inch PVC hose. It drains faster than I can fill the box with a city water hose. One clamp only: it's above the waterline, with no pressure. Outside, the old hole is patched, sanded and faired, ready for primer.

90 feet of 5/16 G40 goes into the box easily, with about 10–15 inches left above for the windlass drop.

The bow roller

Installing the bow roller at 100 °F was a challenge by itself. The main problem: I had to disconnect the forestay to drill and tap through the bow plate. The roller has two screws at the back and one at the front. The front one only takes side load, and there's no way to get a nut under it, so I tapped the bow plate and screwed into it. The back screws go through the deck, with nuts and big washers underneath. I added a stainless plate, as thick as the bow plate, between the deck and the roller, because the front sits on the bow plate and the back on fiberglass.

I'd like a backing plate, but there are two reasons I used wide washers. The surface underneath isn't flat: there's a bump in the middle that would make a stress point and put all the load on a small area. And the windlass can only pull 600 lb, so the loaded area doesn't need to be big. I'm still thinking about a wood block and a couple of bolts at the very back holes, after painting. The chain runs through the roller well, and the CQR fits.

Windlass in

First a dry fit of the mount, then it was installed on six 3/8 bolts. Inside I used 1/4-inch stainless backing plates with tapped holes, because the back of the chain locker is very hard to reach. They're actually old chainplate pieces, glued in place inside, so one person can do the bolts. Everything is sealed with butyl. The holes in the locker are drilled exactly to size and countersunk; the holes in the mount are oversized, so the butyl goes around each bolt. I put lots of butyl on each bolt neck and squeezed it in with wide washers. One bolt sits at the edge of the old closed hole, which is no problem: there the mount only pushes down.

I re-checked the hatch template, and cut and fitted the chain locker hatch.

Then the windlass went on. Three test runs: the anchor and all 90 feet of chain down in 50 feet of water (I know 30 feet was lying on the anchor on the bottom), but OK for a first test. I paid out all the chain and pulled it back. Everything worked; the box takes the whole chain without my help. Once I accidentally "caught" the dock and tried to lift it, or to sink the boat. So without meaning to, I tested the windlass at full load. The windlass, the mount and the roller all survived. The dock too.

Here's the final view. It looks like it was part of the original design.

Its own battery

I decided that the windlass gets its own battery. Why?

• I had a nice 55 Ah AGM battery.
• 15–20 feet shorter cables between the battery and the windlass.
• Even if I drain it completely, I can still start the engine and have power for the house.
• I can always recharge it from other sources.
• A spare battery on board is always nice.

So: the battery, a 50 A breaker on the positive, a shunt for the battery monitor on the negative, and a 4-pole solenoid relay, controlled by a 2-channel 433 MHz wireless remote module. To "marinize" it I coated the board with polyurethane conformal coating and put it in a sealed box. Here are the controls and the solenoid on their mounting block, tested before the install, then installed, with the back plate glued to the hull with epoxy and 404. The battery goes under the V-berth on the starboard side. The breaker will be inside the cabinet, doubling as a battery switch. A 12 AWG charger cable runs to the battery, with its own fuse at the battery. Then a temporary "dry fit" electrical check.

The same day I put a class-T 300 A fuse on the lithium battery bank.

In September the windlass battery and breaker setup was finished. The charging cable negative goes to the load side of the shunt, and the positive has an inline 15 A fuse. The windlass negative goes to the shunt, and the positive to the 50 A breaker. Still to do: connect the battery monitor and run its wires to the main battery box, a battery cover, a strap, an LED that shows the windlass is powered, and maybe a cut-off relay from the cockpit.

In October the battery got a custom plastic cover, and the bow got foot switches. I had to re-crimp the control wires to the solenoid and add one more inline fuse.

In November the battery was strapped down. I pulled out the chain and marked 40, 60 and 80 feet with pieces of webbing.

The hatch, finally with a latch

The previous owner had put mild steel piano hinges on the chain locker hatch, and they were completely rusted. And the original design had no latch at all. I patched and sanded the hatch and split it in two. The front part comes off without hinges. The back, bigger part is hinged. I sanded landing pads for the hinges and reinforced the hatch there, and added a lip on the hinged part that overlaps the front piece and holds it down when closed. The handle looks like the old rectangular one, but it latches. I also lowered the hinge landings on the deck, so you don't trip on them. Then all the hardware came off the bow, everything was sanded, and unnecessary holes were glassed over, sanded and faired.

One more surprise from the previous owner. He had ended the lifelines on extra stanchions and rails, so the jib goes out without rubbing on the lifelines. Smart. BUT those stanchion bases were screwed to the deck with self-tappers. They'll need through-bolts and backing plates.

At the end of September the pulpit went back on 3M 4000 UV (mainly so the tapped threads in the glass don't fill with butyl), with the original screws. The lifeline rails and cleats were bedded on butyl. The hatch is now in two halves: the front one removable and locked with a turn latch, and the back one on hinges, opening from starboard to port, with a latching handle, so the chain can't dump out if the boat ever goes upside down. Hopefully it never will. Here's the latch cam, and one more view of the bow. That's it for that day.

The deck was painted, the foot buttons installed, and the anchor connected and sitting on the roller.

Anchor control on the NavPod

In May 2026 the NavPod got an Anchor_control screen. What's working so far: a custom anchor alarm, speed and course from 10-second averaged positions, the current depth, a "virtual depth map" built over time to estimate the tide compared to when the anchor went down, manual and automatic anchor settings, the current scope, the distance to the anchor, and the wind direction and speed shown on the map.

In March 2026 I put safety wire on the anchor shackles.

A rope-to-chain splice

In September 2026 it was the anchor rode's turn. There are lots of double-braid anchor ropes, but how do people splice them to chain so it goes through the windlass? A normal eye splice makes the joint too big and stiff for the gypsy. My solution: unbraid the core and the cover (keeping the strands intact), rebraid them as an 8-strand rope (the core is 8-strand anyway), then do an 8-strand rope-to-chain splice. Maybe it's temporary, but it doesn't look bad.

Cracked shackles

November 2026. After two years I decided to replace the windlass motor with a brand new one. Mine sometimes lost power on long, hard pulls. I know why: when I repaired it, I couldn't find the right brush springs and used what I had, and probably one spring loses strength when the brush gets hot. I'll replace the springs and keep the old motor as a spare.

During that work Vic found that both shackles on the anchor chain were cracked. When I took the pins out, I could break them in half by hand. I can't imagine how I didn't lose my anchor!!!! I replaced them with galvanized ones. There's really no point in stainless shackles between a galvanized anchor and galvanized chain.