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Electric Winches Q&A

General Information

Why should I equip my boat with electric winches?
Electric winches make it possible to sail bigger boats shorthanded. Crew can perform any task onboard, regardless of their strength, size, or physical condition. With the push of a button, crew can sheet the jib in high winds and execute other heavily-loaded tasks. Jobs such as trimming the mainsail are effortless. When conditions get rough, trimming by push button often allows you to keep sailing instead of motoring.

Do all electric winches have two speeds? 
Harken electric winches are 2-speed in both manual and electric modes, while some manufacturers' electric winches are 2-speed in manual mode, but only one speed in electric. The ability to choose a winch operating speed is always an advantage. For example, in light air you can sheet the genoa with the fast first gear and fine-tune in second.

For fast line speeds, winches size 60 and up can be special-ordered with three speeds.

How do I switch gears?
You can press one of two switch buttons for the desired speed.

What systems should I power?
Electric winch systems commonly trim the genoa sheets and the main halyard. In many cases, it's possible to lead the main halyard back to a powered primary winch. In addition, electric winches can furl mainsails, raise the anchor, or help dock the boat.

How do I size electric winches? 
Always size electric winches for the highest load. For example, if you use the winch for both the halyard and genoa sheet, size the winch for the load of the genoa sheet. See Ordering Winches.

Can I use a winch handle to manually operate my electric winch?
Yes. Inserting the winch handle into an unloaded winch automatically disconnects the electric motor and allows you to use the first and second speeds just like a manual winch. This is important if you've lost power on the boat. If power is restored, the lockout prevents the winch handle from turning. 

Switches are also available with guard covers to prevent accidental starts.

Is there a racing disconnect for powered Radial® winches?
No. Permanent racing disconnect rods are not available for Radials at this time. However, all Harken electric winches automatically disconnect the motor when a handle is inserted. The main difference is the handle disconnect is easier to release. The only thing to be careful of is that the winch handle is properly locked so the pin doesn't push the handle out of the socket.

What is the best location for a single electric winch?
Harken winch motors are small and come in horizontal or vertical configurations to fit a variety of spaces. Cabin top-mounted winches are great for halyards. Smaller boats may find there is more room for the motor and gearbox in the primary position. Lead halyards to these winches by running them to a snatch block mounted near the gunwale and then to the winch.

I'd like to mount an electric winch on the cabin top, but it limits space below. Any suggestions?
Yes. The Harken UniPower™ 900 single-speed electric winch has a motor that is partially embedded inside the drum and extends only 105 mm (4-1/8") below the base. This gives crew more head room as well as space to move around.

How many speeds does the UniPower have?
The UniPower is a single-speed winch that combines the advantages of a low-profile manual winch with the power of a 12-volt or 24-volt, low-amp-draw motor. It has a maximum pull of 900 kg (1984 lb) Harken's WLC200R load controller keeps the winch from exceeding this limit. In case the boat loses power, the winch can be operated manually using a winch handle.

What's the UniPower's line speed?
Line speed under no load is 25 m/min (82 ft/min).

What's the difference between a standard electric winch and the Rewind™ electric winch?
The Rewind™ works like a standard Harken 2-speed winch, but engage the rewind function and you can trim in both directions. This means you don't have to sit on the low side to trim. Instead a set of buttons installed on the high side or at the helm lets you trim in or trim out without going to the winch and unwrapping the sheet.

For more information see the complete Rewind Electric Winch Q&A.

Can I tie my boat off to the dock using the self tailer? 
This is a very bad idea. Wind, tide, currents, and waves from powerboats constantly vary the loads on the self tailer and it could bend. Instead use spring lines to prevent fore and aft motion, and long bow and stern lines to prevent the boat swinging in and out.It also helps to attach dock lines to cleats or pilings that are at the same level as the cleats on the boat at mid tide.

Is it easy to convert my manual winch to electric?
Manual Radial® winches easily convert to electric or hydraulic power. They don't require an adapter plate, and the identical stud pattern means you don't have to fill old holes and drill new ones. To convert older style manual winches to power, please contact Harken.

General Radial® Information

How to I find the serial number on my Radial winch?
The serial number should be apparent when you take off the drum. It is on the drum support, just below the lower red roller-bearing cage.

Do all winches have part numbers?
No, only the Radial and Performa™ lines, which includes the electric, hydraulic, UniPower, and Rewind models.

Why is the drum narrower at the bottom?
This shape combined with the surface grip keeps the line low on the drum, providing efficient and trouble-free operation.


How much electricity do electric winches use?
Although electric winches can consume as much as 150 to 200 amps, they do not run for long periods of time. A day's use might amount to no more than 10 minutes. Many sailors measure the amp-hours used for each electrical device, calculate their total electrical needs, and match this to battery capacity.

How do winches of different speeds affect battery drain?
A Harken 2-speed winch drains less power from the battery because it offers the mechanical advantage of a second gear. A single-speed winch operates in the motor's upper range and draws more amps. Because line speed slows dramatically in the upper range, time of use is comparable to 2-speed, but amperage draw is greater.

How do I determine my battery requirements?
Calculate the amount of electricity you need for all systems per charging period. Compare this number to your battery capacity. For optimal battery life and performance, your battery capacity should be three times the daily draw. For example, if electrical draw is 100 amp-hours per day, you will need 300 amp-hours of battery capacity.

What is an amp-hour? How is it measured?
Multiplying amps by hours of use yields the amp-hour measurement. For example, an electric winch that uses 100 amps for 12 minutes (.2 hour) per charging period consumes 20 amp-hours (100 x .2). To calculate your battery requirements, total this number with other systems on the boat.

How many amp-hours will an electric winch use per day?
Winch amp-hours vary according to voltage, winch size, and the frequency of operation between charging periods. If you have a 24-volt system, you will use 30 to 35 amp-hours per day. With a 12-volt system, you will use 50 to 55 amp-hours. Larger winches—66and up—use 50 to 55 amps at 24 volts.

How do I check that my battery and charging system can accommodate my estimated amp-hours? 
Digital amp-hour meters will display the number of amp-hours consumed by winches and your other electrical systems, including charging sources. You can also buy volt meters and meters for monitoring your battery and charging system. If your boat has no metering system, you can purchase one with all three functions in one meter.

Does it matter whether I have a 12 or 24-volt system?
Check your system and specify voltage when ordering. Most boats in the US are 12-volt. Boats using 24-volt systems are more common in Europe. Because a 24-volt system requires half as much amperage, the wire and circuit breaker (fuse) can have lower amperage. Larger winches, such as the 1110, 1120, and 1140, are available in 24-volt.

Should I have a separate battery for electric winches?
No. It is best to have a bank of batteries to run your electrical components. A bank of batteries allows a slow draw from a large electrical supply and provides better battery performance. It's a good idea to install a separate battery system to start the engine to ensure enough power is always available.

What type of batteries do I need? 
You need deep-cycle batteries designed for deep discharges and repeated charge/discharge cycles. Gel batteries can handle deep discharges and are maintenance free. Wet-type marine batteries are less expensive, but require maintenance. Premium versions of wet batteries offer the longest life, but are the most expensive and require maintenance.

Do I need anything else?
You will need wire, two switches, a control box, and a circuit breaker. We also recommend adding an optional load controller to protect your winches from overload. Match wire size to the size of the winch, system voltage, and wire length. Harken offers five high-amperage, waterproof circuit breakers, 12 and 24 volts DC.

What maintenance is required?
You should check electrical connections and monitor the battery charge, but electric winches are otherwise serviced like manual ones. Remove old grease with a mild solvent and apply a light coat of grease on the gears. Oil the pawls and springs periodically.

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Rewind™ Radial®

The Rewind™ operates like a 2-speed winch—fast trimming in first gear and more power in second. Turn the red knob to engage the Rewind function, and you can trim in and ease out remotely without going to the winch and unwrapping the sheet.

Standard Electric Winches

Electric Radial winches offer cruising sailors the convenience of a push-button, easily-installed system. It's a simple task to convert from a manual Radial to electric power because the stud pattern is the same for both.

All Harken standard powered winches (even the smallest) drive through the winch's 2-speed transmission—first gear for speed, second for power. Harken motors attach directly to the drive shaft, so the gears turn the winch. This results in less drain on the battery with a smaller, more efficient motor to drive the winch.

Electric Radials are available with vertical or horizontal motors.


A Harken UniPower™ 900 electric winch on your cabin top, lets you raise your sails with the touch of a button. Even small yachts can now enjoy this convenience—the UniPower has a partially embedded motor to preserve headroom below.

Need a hand with your sheets? The Harken UniPower 900 also makes a great single-speed mainsheet or primary winch for boats up to 13 m (43'). Unlike typical powered winches, it’s an energy-efficient solution with no power lost to retrofit gearing.


Rewind Electric Winches Q&A
Choosing Winch Power