Do You Want a Headsail Luff-groove Device?

Just 15 years ago, one of the hardest jobs on the foredeck of a racing boat was to make a quick headsail change.


Unless the boat was equipped with two headstays, which adds considerable windage, the headsail change drill meant releasing the lowest hanks on the headsail in use, tacking down the new sail, hanking it on below the head-sail already up, taking a deep breath, letting the jib halyard run, then going like mad to get the hanks open on the old jib, all the time listening to the skipper scream to hurry up.

No wonder it was a lousy job.

In 1969, Hood introduced the Sea Stay, a grooved rod headstay that reduced windage by eliminating jib hanks. The concept was further refined by other manufacturers, and a variety of modifications on the basic Hood principle followed. These include grooved aluminum extrusions that replace the headstay, such as Hyde Stream Stay, sectional aluminum extrusions that fit over the existing headstay, such as Hood’s Gemini, and plastic extrusions which fit over the headstay, such as Head Foil.

While luff-groove devices were developed for racing, they have been incorporated in modern headsail roller furling gear to eliminate some of the problems associated with old-style roller furling: most notably, the almost uncontrollable headstay sag which reduced winward performance, and the difficulty of handling sails with heavy luff wires. Most modern headsail furling systems utilize some form of luff groove device, most of which are designed specifically for use with that roller furling gear. If you already have a luff groove device, you probably won’t be able to adapt it to a roller furling system if you decide to go cruising rather than racing.

For racing, there are two primary advantages to a luff-groove device. First, it will make the leading edge of the headsail aerodynamically cleaner. There will be no wrinkles radiating from jib hanks, as the halyard load is evenly distributed along the luff of the sail. The “spoiler” effect of jib hanks protruding into the windstream is eliminated, and there is no open slot between the headstay and the leading edge of the sail, further reducing turbulence.

In addition, it is not necessary to lower one jib before setting another. While this doesn’t mean that the foredeck crew can get lazy -when two jibs are up simultaneously on the same tack, both are quite inefficient -but it does relieve a little of the hurried fumbling on the foredeck that undoubtedly can put the bowman in danger. A bowman being yelled at to hurry up with getting the new jib on is likely to ignore, or forget about, “one hand for the ship, and one for yourself ” in the effort to speed up the headsail change.

For the racer, then, the luff-groove device is practically essential. In fact, the advantages of the luff groove device are recognized by the two major rating rules, IOR and MHS, which add twice the fore and aft dimension of the luff groove device to the LP of the largest genoa to determine the boat’s headsail area, This is powerful evidence of the efficiency of the luff-groove device.

Do they offer advantages to the sailor who doesn’t race? Unless the luff-groove device is incorporated in the head-sail furling system, the primary advantage for the cruising sailor is the ability to set two headsails at once for downward sailing without a spinnaker. If you have two jib halyards, two jibs can be fed into the twin grooves of the luff-groove device, and sheeted to opposite sides of the boat. This eliminates the twin headstays, with their excess windage and difficulty of tensioning, that are frequently seen on far-ranging cruising boats.

In most other ways, however, the luff-groove device is a questionable luxury for the cruiser, particularly if shorthanded sailing is on the menu. With a hanked-on jib, releasing the halyard usually results in the jib falling to the deck, still attached to the stay for the full length of the luff. If the boat is equipped with lifeline nets, and the boat is brought head to wind or nearly head to wind before the halyard is released, the jib may stay completely on deck in a relatively docile bundle.

Releasing the halyard of a sail set in a luff groove device is another matter. Usually, there is enough friction in the system that the sail doesn’t fall to the deck. For the shorthanded sailor, it’s a good thing that the sail stays put, for a lowered jib set in a luff-groove device is attached to the boat only by the halyard, the sheet, and the tack. Handling a genoa in heavy weather, alone on the foredeck of even a small boat, when the luff is entirely free is a character-building experience most of us can do without.

If you are converting from hank-on sails to a luff tape for a grooved device, most sailmakers will charge about $2.50 per foot of luff length to make the alteration, or about $110 per sail for a masthead 34-footer. In addition, the luff groove device itself will cost $400 to $450 for the same boat. Pricing of the various devices is quite competitive despite differences in design and materials.

If you are having new sails built, the cost of hank-on jibs and luff-groove jibs is usually the same, so there will be no additional cost of doing the conversion from one system to the other.

While there is little doubt that racing improves the breed, not all racing innovations are practical for the cruiser. Mainsheet travelers, efficient winches, blocks, and deck hardware have a racing heritage, as does the luff-groove device. When incorporated in a modern roller furling system, the luff-groove device has a place on the cruising sailboat or even the daysailer. For the sailor who is more than casual about racing, and who always has plenty of crew available, the luff-groove device -without roller furling gear -is an essential piece of equipment.

For the rest of us, there are dozens of better places to spend a big chunk of money: better navigation or safety equipment, even the down payment on a new genoa. Or hiring someone to help put a good bottom on the boat. Or if you’re really desperate, spend it somewhere around the house, so your spouse won’t scream so loudly next time you propose to spend the entire income tax refund on some nautical toy only you can appreciate.

Do You Want a Headsail Luff-groove Device?

Practical Sailor has been independently testing and reporting on marine products for serious sailors for more than 45 years. Supported entirely by subscribers, Practical Sailor accepts no advertising or any form of compensation from manufacturers whose products we test. Testing is carried out by a team of experts from a wide range of fields including marine electronics, marine safety, marine surveying, sailboat rigging, sailmaking, engineering, ocean sailing, sailboat racing, and sailboat construction and design. This diversity of expertise allows us to carry out in-depth, objective evaluation of virtually every product available to serious sailors. Practical Sailor is edited by Darrell Nicholson, a long-time liveaboard sailor and trans-Pacific cruiser with more than three decades of experience as a marine writer, photographer, boat captain, and product tester. Before taking on the editor’s position at Practical Sailor, Darrell was the editor of Offshore magazine, a boating-lifestyle magazine serving the New England area. Darrell has won multiple awards from Boating Writer’s International, including the Monk Farnham award for editorial excellence. He holds a U.S. Coast Guard 100-ton Master license and has worked as a harbor pilot and skippered a variety of commercial charter boats.


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