Everything You Need to Know About Boat Trailer Winches

Your boat trailer winch works hard. It has to retrieve a wet boat weighing hundreds of kilos, and bring it up perfectly centred onto a few slippery rollers, all on a steep slope.

If you are like many other boat owners, you may dread the launch and retrieval part of the day. There’s plenty of stress when getting your boat off or onto the trailer quickly without any damage to the car, boat or crew. Some skippers upgrade their trailer winch to make the task easier and minimize stress and hassle.

There are two kinds of boat trailer winches – manual (muscle power) and electric (12v). With each type, it’s essential to make sure it is suited to your boat’s length and weight.

How Boat Trailer Winches Work: Electric vs Manual

Manual Winch

The hand-cranked manual winch method and components have changed little in the past few decades. The crank pulls the line in to be stored on the drum. The windlass, a horizontal-axle rotating machine, maintains tension while the ratchet lock prevents slipping and a gearbox allows for winching at different speeds or ratios.
The gearbox has three main speeds:

  • 1:1 ratio – for winding up the line once the boat has been launched into the water
  • 3:1 ratio – for pulling lighter boats onto the trailer
  • 5:1 & above – for pulling a heavier boat onto the trailer without the assistance of water (e.g. it is completely out of the water)

Electric Winch

Instead of a crank handle and muscle power, the electric winch is hooked up to a 12-volt battery and uses variable speed high gear ratios.

Most standard electric winches will have basic features like being able to power in and freewheel out. The winch motor pulls the boat on to the trailer. Freewheel or float means gravity is used to float the boat into the water. The only case where this is not true is with the Powerwinch 915 which has a power-out control that assists with releasing the boat into the water by slowing releasing the gear. Trailer winch models are based on the size of boat they need to pull out of the water – small (3 metres), mid (5 metres) and large (7 metres). A maximum boat weight also ensures the winch is suited to your boat.

Some electric winches have a smooth pulling action and less amperage draw. A level wind system helps prevent snarls and wear in the cable.

Why Choose an Electric Winch?

The cost of an electric winch is more than a manual one, so the advantages need to justify the additional cost.

Some of the reasons for using an electric winch include:

  • Boat size – the length and weight means it can’t be manually winched
  • Skipper strength – if you aren’t strong or nimble enough to manually winch the boat
  • Speed – an electric winch can make it a little quicker to retrieve a boat
  • Safety – the risk of accident and hull damage can be minimized by electric winching


Trailer Winch Capacity

Choose your trailer winch based on its Safe Working Load (SWL) capacity and the weight of your boat. Remember to include the weight of your motor, fuel and equipment, not just an empty hull.

There are some factors to consider when deciding on the winch. If you usually launch on a steep ramp, you will need a bigger capacity winch than if you winch on a gentle slope ramp. Your trailer has an impact on how much your boat slides and therefore how hard your winch has to work. If you are using rollers, there is less resistance than carpeted wood bunks so a smaller winch will do the job.

Regarding cranking resistance, lighter boats can use a manual winch with a 3:1, 4:1 or 5:1 gear ratio. For a 3:1 ratio you turn the handle three times for the drum to rotate once.

For heavier boats, a two-speed winch may be required to give you the option of a quick pull-in ratio and a second low speed with a ratio around 16.2:1 for increased mechanical advantage. If the two-speed manual winch isn’t strong enough, it might be worth moving to an electric winch that has variable speed and high gear ratios.


How to Service & Maintain a Boat Winch

Your winch is one of the hardest working parts on your boat and trailer. Winches and their accessories are fairly easy to maintain and replace. If you have owned your trailer winch for a few years and given it little to no love, it’s time to do some maintenance.

The level of maintenance your boat trailer requires will depend on the type of water your boat is launched and retrieved in. If you only use your boat in the ocean, your boat’s maintenance schedule will be different to one that is only launched in freshwater.

Some winches are rated for a number of hours of exposure to saltwater but you still need to make sure you hose down your trailer and winch with fresh water after every trip. A few minutes of your time can extend the life of your winch.

Manual Winch Maintenance

After each trip check if the strap is wet or dry. A wet strap will deteriorate faster and place the drum at risk of corrosion. Pull the strap out its full length and let it dry before winding up again.

Check the winch line regularly for signs of fraying. If you notice any fraying or areas of wear, replace the rope, strap, and cable. You don’t want the strap breaking whilst you are retrieving the boat as this has the potential to cause an injury.

Non galvanized winch gears are particularly prone to corrosion. Use a marine grease to lubricate them, then do the same for the shaft and bushes. Use wire rope lubricant regularly on the cable’s strands so they slide over each other with a minimum of friction.

When the boat is off the trailer, check the rollers. They should move freely and not show any signs of damage. If there is any damage, replace the roller. You may be surprised how much easier it is to retrieve your boat after replacing a roller.

If you see any rust or signs of corrosion on the winch, use a wire brush to remove it and a galvanising compound to prevent more corrosion.

There are parts of a manual winch you can’t inspect without taking them apart. Your trailer winch will have a long life if you take it apart once a year to check the moving parts and to apply grease.

Electric Winch Maintenance & Servicing

Once a year, clean and check your electrical trailer winch. Take off the cover and lubricate the gears with a lithium-based grease but be careful not to spread grease on the clutch lining. Lubricate the cable with WD40 or a similar product by spraying the shaft and cable while the cable is being wound. If the cable is worn or frayed anywhere along the length, buy a new one.

When replacing cable, be sure to buy the same cable type to ensure the winch rating and cable strength are matched for both performance and safety. When replacing the cable wear leather gloves and follow the manufacturer’s instructions.

Tips for Using a Trailer Winch

If you are using an electric winch, remember to keep your car’s motor running to reduce the drain on your battery. You don’t want to retrieve your boat only to get back into the car and find you can’t drive off the boat ramp because the battery has died. Don’t overlook your car’s battery. If it’s being used to power your winch, you don’t want any problems on the ramp. Clean the battery terminals and check its charge before hooking up.

If you are using a manual winch, be careful on the ramp. Before you start winching, make sure you have a firm footing and good leverage as ramps are often slippery. Also, be aware that the winch handle can kick back and injure you at any time. You can download a handy guide to boat ramp safety and etiquette here.

Don’t rely on your winch to hold the boat on the trailer while travelling – that’s not its job! Instead, use dedicated boat tie downs to ensure the boat and trailer stay connected while you are driving on the road.

It’s important that your winch and boat weight are a match at the time of purchase and later on. Your boat’s weight is rarely the same when you take trip after trip. The boat shouldn’t exceed more than 75% of the winch’s weight rating. This will allow for a steep incline on a boat ramp or poor weather conditions which effectively add weight to the boat.

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