Onne van der Wal photo

Harken Battcar System

A low-friction Harken CB (captive bearing) Battcar system lets you quickly raise, reef, and douse your full-battened main on all points of sail from the safety of the cockpit. It's a dependable ‘extra hand’ when you’re sailing alone or with inexperienced crew—no matter what the weather.

Installing a new Battcar system is a big project, so if you have any questions, don’t hesitate to email Harken Technical Service or call us at 262-691-3320.

Tech Tips:
Our low-friction Battcars drop the main so fast that we advise a wrap on the halyard winch to slow your takedown and maintain control.

Lazy JacksLazy Jacks contain the main on the boom while dousing to give you
better visibility as you approach the mooring.

Battcar Systems Q&A


General Information

A Harken Battcar System is a simple, low-cost solution to a problem that seems bigger than it is. Battcars let you raise, lower, and reef at any wind angle while enjoying efficient sail shape underway. Adding a Harken Lazy Jack to your system makes dropping and reefing the sail even easier by gathering the mainsail on the boom.

Sail AreaWhy choose Battcars instead of in-boom or in-mast furling?
No hidden costs: a basic in-boom or in-mast furling system costs 4 to 6 times as much as a top-of-the-line Battcar system. With ball bearing Battcars, you don't need a new boom, running rigging, mast, mainsail, or professional installation. The system is so free of friction that you'll never need an electric winch as long as you can hoist the weight of the sail.

Proven reliability: Battcars have a simple, robust design that withstands years of extreme mainsail loads. Top solo circumnavigators trust these systems to take them around the world.

Sail efficiency: In-boom and in-mast furlers generally require smaller and flatter custom-designed sails so they can roll properly. Battcars let you keep the performance of your existing sail.

Do Battcar systems make it safer to sail shorthanded or by myself?
Yes. One of the most difficult things to do safely when sailing alone or shorthanded is reefing the main. This is usually a two-person job—you either need one crew to pull the luff of the sail down to reef or the skipper has to turn head-to-wind to lower the sail to a reef position.

You can lower Battcars at any time when the sail is not pressed against the spreaders—in any condition, at any wind angle, and without having someone go forward. Just let off the halyard to one of the reefing positions you've marked on it.

What system size do I need for my boat? 
Using the table below, select your system based on mainsail area and hull type (boat length is only an estimate). Standard Battcars fit boats from as small as 6.5 meter Mini Transats (21 feet) to as large as 30 m (100-foot) megayachts. We offer custom systems for yachts over 30 m (100 feet). 

Typical Boat Length
Maximum Sail Area
System Size
to 37
to 11.3
to 30
to 9.1

How do I approach my mooring with a Battcar system?
It's easy. A Battcar system combined with a set of Lazy Jacks lets you sail almost right up to a mooring. When you release the halyard, the sail drops between the Lazy Jacks into a neat stack and stays on the boom. You'll have excellent visibility as you approach the buoy.

Can Battcars help me if a squall comes up with little warning? 
Battcars are perfect for these conditions. If you need to get your sail down in a hurry, let the halyard go and it will drop immediately regardless of the load. We recommend keeping a wrap on the winch to slow the take-down and maintain control.

I have a full-battened mainsail. What modifications do I have to make?
Quick Release Pin (Top); Attaches w/Slugs (bottom)  Harken makes cars that accommodate most batten receptacles on the market. All you need is to have your sailmaker add webbing for the intermediate luff cars. 

Is the mainsail easy to remove?
All ball bearing Battcar systems feature captive bearings to make them easy to remove from the mast. No more balls bouncing everywhere. Battcar systems B and C have quick-release pins that let you quickly detach the sail without removing the cars.

What are the benefits of installing the Harken system? 
In addition to being able to keep your existing mainsail, Battcar track attaches to your existing spar with slugs that fit inside the sail groove on your mast. Grooved aluminum production masts don't need to be drilled or tapped. If you're handy, you can install the system yourself.

Harken: Battcar TrackWhat if I don't have a grooved mast?
You can drill and tap your mast to install standard Harken traveler track in place of slug-mount track. Drilling and tapping requires a little more care and expertise to do yourself, but even with professional installation it is still far less expensive than installing an in-boom or in-mast furler.

How can I save money and still get performance using a Battcar system?
We recommend using ball bearing Battcars at the battens and headboard because these carry the highest loads. However, installing slider cars at the intermediate luff positions will reduce weight, cost, and stack height.

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