Switching to Electric Winches

I’ve always liked the shape of the fully battened mainsail on Caretta, my tall rig Catalina 380 sloop. But my aging north-of-65 body no longer enjoys cranking it all the way to the top of the mast. Here’s how I upgraded my Lewmar winch for push-button operation.

I’ve always liked the shape of the fully battened mainsail on Caretta, my tall rig Catalina 380 sloop. But my aging north-of-65 body no longer enjoys cranking it all the way to the top of the mast. When I found myself daysailing in light air with a partially reefed main, I decided it was time to replace my manual Lewmar ST40 halyard winch with an electric one. Luckily, I didn’t have to purchase a whole new winch—Lewmar, like Harken and Andersen, sells conversion kits for its existing two-speed winches. Here’s how I upgraded my Lewmar winch for push-button operation. (The procedure for a Harken or other winch will be similar.)

To make such a conversion, you need room under the winch for a horizontally mounted gearbox and motor. In Caretta’s case, I also had to drill a 2½in-diameter hole in the coachroof to accommodate the winch motor’s drive shaft, and I had to run several heavy-duty #1/0 gauge wires. In other words, serious pre-installation planning is vital.

One of the main components of the Lewmar conversion kit is a base plate with a 2¼in outer diameter flange that extends through the boat’s coachroof or deck. Your converted winch will sit on this baseplate, which also houses the shaft seal and drive shaft. A belowdecks coupling attaches to the base of the flange, and the electric motor bolts to this coupling.

Another major component is a new winch center stem (the metal component that houses all the winch’s gears and bearings). This stem, which includes a hole to accommodate the drive shaft, bolts to a set of threaded holes in the base plate, an arrangement that allows you to remove the winch for servicing without having to disconnect the baseplate, motor and driveshaft.

The first step in the conversion is to remove the existing winch and clean the pad. You will re-use almost everything from your existing ST-40, except for the center stem, one lower ratchet gear and the mounting bolts.

You will probably want to use the same winch pad for your EST-40 that was used for your manual ST-40. Most production boats have an aluminum plate glassed in below the winch pads, which can be drilled and tapped for mounting bolts. Be prepared to drill your 2½in-diameter drive shaft hole through fiberglass, wood and aluminum.

My only complaint with the Lewmar kit is that it did not include a scaled template. Instead, we made one using tracing paper with the new center stem as a guide. This is a critical step, because the drive shaft hole is offset from the center of the winch, and the gearbox/motor can be rotated in 90 degree steps to suit one of four below deck mounting configurations. On Caretta, we were fortunate in that the after-most mounting configuration provided just enough room for the gearbox to clear a bulkhead. However, because of the relatively short length of the baseplate’s flange, I had to cut out a complete shadow of the gearbox and motor assembly from the boat’s headliner. I learned later that an extension kit is available by special order.

Once the drive shaft hole has been drilled, you can insert the baseplate and drill the plate’s mounting holes. If you are lucky, you might be able to use one of the existing holes. We elected to drill through the coach roof and through-bolt the baseplate after setting it in copious amounts of sealant. Note that you will need to use flat-head screws for mounting the baseplate in order for the center stem to properly mate with the baseplate. You will also have to drill a 1in-diameter hole for the push-button deck switch. Lewmar does provide a template for the deck switch. I mounted mine about 7in outboard of the winch, where I had a clear view of the winch, mainsail track and reef lines.

Now for the belowdeck work! I found it easy to mount the coupling to the bottom of the baseplate’s flange. But it was a real bear mounting the gearbox and motor to the coupling. The assembly is heavy, weighing approximately 36lb. Holding it above your head while trying to engage four barely accessible hex bolts borders on the impossible. We solved the problem by buying a 7in-long bolt with two fender washers and a nut at the local hardware store. The bolt was inserted from the coach roof through the baseplate, coupling and gearbox, where the driveshaft would normally go. The 7in-long bolt supported the gearbox/motor assembly while we painstakingly tightened the hex bolts that secured the assembly to the coupling. It still took us over two hours to tighten these bolts, because we could get less the one eighth of a turn with a stubby wrench on each attempt. You may have slightly better access on your boat, but I would still recommend using the long bolt and fender washer approach.

Once the motor is secured to the coupling, you simply remove the long bolt, pop out the shaft bearing, slide it up the driveshaft far enough to insert the key and then insert the driveshaft assembly—complete with key and bearing—into the baseplate’s flange.

The final mechanical task is reinstalling your winch using the new center stem and lower ratchet gear. This ratchet gear, which sits in a cup atop the drive shaft, is what actually turns the winch when power is applied. Your converted winch will sit slightly higher due to the addition of the baseplate. Lewmar provides a black plastic ring that is inserted between the baseplate and center stem to cover the metal baseplate.

The conversion kit also includes a 90-amp breaker, a “contactor” solenoid switch, and the previously mentioned deck switch. We installed the breaker in the positive lead from the house bank to the selector switch. From the common connection at the selector switch, we ran red #1/0 gauge cable to the contactor, which we mounted in a space behind Caretta’s distribution panel. From the contactor’s other terminal we ran red #1/0 gauge cable along a wiring raceway and thence, with the help of only one new inspection port, between the headliner and topside to the electric motor. The black #1/0 ground cable from the motor was run along the same raceway to the negative bus at the distribution panel. After estimating the lengths of the #1/0 gauge cable r

uns, we had the connectors crimped on professionally at a battery shop. You will also have to run several small gauge wires between the deck switch, contactor and electric motor. However, these are easy to work with and their installation is well documented in Lewmar’s manual.

Expect to spend between $300 and $400 above the cost of the kit for wires, connectors and bolts. Also, be warned that this is a full two-day job. I suppose a creative, mechanically inclined individual could do the job alone, but it helps to have a second person for at least half the time.

The Lewmar kit components were top notch and meshed precisely. The electric winch now hoists my main all the way up my mast in less than a third of the time it was taking me to do it manually. From now on, if you see Caretta sailing in light–to-moderate air, she will be flying her full main.

An increasing number of new boats are specified with electric sheet and halyard winches, but replacing the manual winches on an older cruiser is an expensive exercise—a new Harken 50 electric self-tailer will run you close to $5,000, for instance, while a conversion kit will be approximately half that. A single electric self-tailer on a cruising boat can be very useful, not just for hoisting the mainsail but for other duties that involve heavily loaded lines; retrieving a stern anchor, for instance. A few strategically placed snatch blocks to lead other lines to the winch make it a versatile extra hand on board. Lewmar, Antal, Harken and Andersen all offer kits to convert existing winches to power. It’s not an inexpensive exercise, but can be well worthwhile.

A semi-retired engineer, Steve Dublin lives in Fort Lauderdale. He and his wife, Lucy, spend the summer cruising the Bahamas in their 38 foot sloop, Caretta.

Photo courtesy of Anderson; illustration by Alastair Garrod