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ESP Jib Reefing & Furling


Fewer components make this affordable furler quick to assemble and easy to use, while providing the same styling, durability, and low maintenance bearing system of our performance line.

Install an ESP and trim safely from the cockpit when it blows and unfurl instead of motoring when it's light for a great day of sailing.

Harken ESP furlers don’t require professional installation.

Tech Tips:

Harken Link Plate

Harken Link Plate Leg Extension Kits
Choose long legs with standard turnbuckles using swage, Norseman, or Sta-Lok® terminals; short legs when attaching directly to the marine eye at the lower end of the stay.

The 7404 Jib Reefing and Furling lead block kit reroutes lines outside the stanchions for a cleaner deck. A ratchet block is included in the lead block kit to keep tension on the furling lines. This will prevent the line from overriding in the drum.

Harken Lead Block Kit The 7402 Ratchet block offers total control over your furling line. The ratchet provides the extra holding power you need for reefing or furling the sail in heavy winds. The static sheave supplies the correct tension to help the line spool smoothly on the drum when unfurling, making it easier to furl the sail again.

ESP Jib Reefing & Furling Q&A


Designed for Cruisers

Clevis PinHeadstay

How do I select the right furling system for my boat?
The Ordering Furling guide explains how to choose a furling unit and accessories for your boat. You will need to know the clevis pin diameter as well as your headstay length and diameter.

What are the differences between Harken's MKIV and ESP cruising furlers?
Both are designed for longevity and ease of use, but the MKIV has additional features that make it more suitable for performance cruising and racing.

FoilsDouble-groove FoilAerodynamic foil profile. Double grooves for faster hoists, douses, and sail changes.Single-groove FoilRound profile for easy rolling. Single groove.

Precut top foils, adjustable bottom foil
Halyard and Tack SwivelsIndependent SwivelsIndependent swivels for improved sail shape.Fixed SwivelFixed swivel.
DrumSplit drum removes for racing.One-piece drum, spool, and guard i.e. fixed drum.

I am an avid cruiser. Occasionally I cruise with my wife and kids, and sometimes I sail alone. Do you have a simple furling system that my family and I can operate easily? One that is dependable and doesn't cost an arm and a leg?Art Schmickter, Great Lakes cruiser

The Harken ESP Jib Reefing and Furling System will fit your needs perfectly. It's simple and affordable, but has the same Harken styling and free-rolling, low-maintenance ball bearing system as our MKIV performance line.You'll be able to reduce and increase sail area quickly to keep your boat balanced and moving—Rick Wilfert, Harken Technical Service


ESP Furling drum and foil

I plan to keep my boat for a long time. Will the ESP furler hold up over the long term without a lot of maintenance?
The round foils are aluminum and are clear anodized for durability. Foil joints are extremely strong and will withstand years of heavy reefing loads.The one-piece drum, spool, and guard is molded from composite. Guardposts are stainless steel for a dependable, long-lasting system.

Trim Angle

How can I reduce heel and get better control with a reefed sail?
For best results, use a sail designed specifically for reefing with your ESP furler. Reefing sails should be designed to have good shape from about 5 to 40 knots. Additional sailshape adjustments can be made by increasing or decreasing halyard tension and by changing genoa lead car positions. After reefing, simply move the car forward so the sheet between the car and clew points to the middle of the luff.

Why do I need more than one jib if I can just reef?
Experienced seamen rarely sail without a heavy-air jib because even the best all-around reefing sails can fail. In a blow, you should change to a reefable heavy-air sail before leaving the harbor. A storm jib is vital for offshore passages because of the possibility of hurricane weather. In light air, having a large, lightweight genoa can make sailing a lot more fun.

Can I change sails with my Harken jib reefing and furling system?
Yes. Changing headsails is simple. Just attach the head and tack to their shackles, pass the luff tape through the prefeeder and feeder, and hoist. The feeder smooths out wrinkles and minor twists in the sail so you can easily raise sail while at the mast or in the cockpit.

What is the proper luff tape for my furler?
ESP Units 0, 1, 2, and 3 use #6 luff tape. #6 luff tape is 0.1875" in diameter (about 5 mm).

Furling clew

Should my new sail be made with a high or low clew?
Most furling sails are designed with a high clew to give the lower part of the sail a better wrap around the foils, and to improve visibility under the sail. A sail with a moderately low clew has the greatest efficiency and will maintain good visibility because the tack of the sail is raised off the deck.

Do I need to alter my sails to fit the ESP Furler?
That depends. If you are replacing another furler, check your sails to see if they have #6 or 5 mm diameter luff tape. With a new installation, specify #6 or 5 mm luff tape when you take your sails to your sailmaker. In addition to adding the luff tape, he will also add a cut-back above and below the sail to allow room for the halyard swivel and lower unit. The installation manual gives all require dimensions in the appendix.

ESP furling adjustable foil

Can I assemble the ESP myself?
Absolutely. One of our major goals when designing the ESP was to make assembly super easy. Your foils will arrive in precut lengths to fit the requirements of your boat. Once assembled, the bottom foil adjusts so you can fine-tune the unit length to fit your boat. Foils slip over most existing headstays without cutting the wire—a huge timesaver.

Harken has easy charts so you can determine which length top foil you need. Determine the furler size you need and then see the appropriate Choosing Top Foil Length chart in the product brochure.

Tools required

What tools do I need?
All you need is a hammer, a Phillips and slotted screwdriver, wrench, side cutters and included hex drivers. No hacksaw required! The bottom foil is adjustable to fine-tune the final length.

Is it easier to install the furler on the mast when the mast is down or up?
If the mast is down for storage or for other work, the assembled furler can be attached and go up with the mast when it is stepped. Removing the stay and raising the assembled furler on a standing mast is best left to experts and professional riggers.

Can I reuse my existing headstay?
Yes. However, when installing a furler, we recommend replacing a headstay wire used in a salt water environment if it is over three years old. Replace every five years if you sail in fresh water.

Halyard deflector installed

I see you offer a Harken halyard deflector as an option. What is a halyard deflector?
The Harken halyard deflector prevents the jib halyard and other halyards (such as a spinnaker or additional jib halyards) from wrapping around the foil. The deflector is easy to install.

What's the difference between a halyard deflector and a halyard restrainer?
A halyard deflector installs on the stay above the foil system and prevents the jib halyard and other halyards from wrapping around the foil.

Halyard restrainer

A halyard restrainer installs on the mast near the top of the foils and keeps the line against the mast. This provides a better angle to the halyard swivel and prevents it from wrapping around the foil. Stainless steel brackets feature hardcoat-anodized aluminum sheaves that accommodate both wire and rope.

You offer two different lower attachment options. Which one is right for me?
If you have a turnbuckle, choose the Long Leg extension kit. Long legs raise the drum to clear the turnbuckle and anchor, reduce sail chafe, and increase visibility. Choose the short leg extension kit when the furler attaches directly to a marine eye at the bottom of the stay. Short legs allow the sail to be closer to the deck.

ESP furling long and short leg extension kits

Is the turnbuckle easy to adjust?
Yes. Removable clamp screws allow legs to pivot out of the way so you can easily adjust the turnbuckle.

My boat doesn't have a turnbuckle. Which kit should I order?
If your boat doesn't have a turnbuckle and you are interested in a low sail tack, you should order a Short Leg extension kit for direct attachment to the marine eye mounted on the end of the stay. Long Leg kits can also work without a turnbuckle to raise the drum to clear the anchor.

7404 Lead Block KitWhat other components do I need for installation?

  1. The 7404 lead block kit has everything you need to lead line aft to the cockpit. The kit features outboard leads to keep the side deck clear and also includes a ratchet block to maintain furling tension for clean spooling and easier furling.
  2. Furling Line: Harken supplied polyester double-braid furling line can also be ordered. If you don't order line from Harken, here's a simple method to determine the length of line you will need. Take the length of your boat and multiply that distance by two. If your boat is 10 m (32 ft), you would order 20 m (64 ft) of line.
  3. Pre-cut and drilled top foil: Harken has easy charts so you can determine which length of top foil you need. Determine the furler size you need and then see the appropriate Choosing Top Foil Length chart in the product brochure.
ESP blocks

Why is it called the ESP furler
If you have ESP blocks you already know this. The name stands for Elegant Simple Products.

What information do you need when I place the order?
Start with your boat length and refer to our typical boat lengths listed for each unit. Next find your wire/rod headstay and clevis pin diameter. Finally check your stay length to see if you need an extra foil and connector.

Questions for Your Sailmaker

What does it cost to add luff tape to my sail?
Costs vary, but most sailmakers base prices on luff and leech lengths.

What brand of sails should I buy?
Select a sailmaker who offers answers that show an understanding of reefing and furling systems.

What size genoa should I use as my primary reefing sail?
This depends on your boat and your normal sailing conditions. Most boats find a 135 percent genoa ideal. Light air 150 and heavier air 100 percent genoas are also common in certain regions. Discuss sail size with your sailmaker.

Can I use my old sails with my new jib reefing and furling system?
Yes. Ask your sailmaker to modify the sails you use regularly, including at least one genoa and one heavy-air sail. If you sail in an area that requires specialty sails like drifters, convert these as well. Sails should be in good condition.

How are sails modified for jib reefing and furling systems?
Your sailmaker will remove the hanks and add a luff tape so the sails slide into the foils. Larger sails may need to be shortened to make room for the halyard swivel. Adding a sun cover to the sails you store furled will protect them from ultraviolet damage.

What should I look for when I purchase a new sail?
Look for a sail designed for a range of wind conditions. The sail should be powerful enough to move the boat in light air and chop, but flat enough to sail reefed in severe conditions. Modern sail shaping devices allow sailmakers to build sails that work in a range of conditions from 5 to 40 knots. Most sailmakers use foam or rope luff pads. Some use the Aeroluff. Ask your sailmaker which shaping device is best for your boat. Adding a sun cover to the sails you store furled will protect them from ultraviolet damage.

Genoa Sail UV-Protection

What's the best way to protect my sail from the sun?
Prolonged exposure to ultraviolet rays deteriorates most sailcloth, so any sail left rolled on the headstay needs protection. Your sailmaker can add UV-resistant material to the foot and leech panels—this can usually be done without adding a lot of extra weight. Most sailmakers prefer to use fabrics like Acrilan (the same material used for mainsail covers).

Alternatively, some sailors use a long sock-like bag to cover their furled sail. This design won't add weight to your genoa but you'll need a spare halyard to hoist it. Be aware these covers can flog in a breeze.

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