Roller furling maintenance


There have been many innovations for cruising sailboats over the last 50 years, but one of the most useful has been roller furling. Manufacturers have fine-tuned these simple yet effective systems into reliable pieces of gear now found on almost all cruising boats. The ease of use along with the added safety of not having to go forward on a pitching deck have made roller furling required gear for both coastal and offshore sailing vessels.

For the most part, today’s roller furlers are reliable and easy to maintain. Should something go wrong, however, it can quickly become a serious problem, particularly with deteriorating weather conditions. The good news is that most of the common problems encountered with furling systems are easily avoided with proper care and maintenance. Although manufacturers have tried to design systems that do not require much maintenance, there are a few things that need to be done to keep your system in good working order.

The first step in maintenance is to make sure your system is properly installed and set up. Many problems with furling systems start with poor installations. With jib furlers one of the most common and often the most serious problem encountered is halyard wrap. This is when the halyard wraps around the furler foil at the top of the mast as the sail is being unrolled. This can damage not only the halyard and foil, but also the stay itself. As this is at the top of the mast, it can be hard to see what the problem is from the deck and often impossible to fix without a trip to the top of the mast.

Preventing halyard wrap

The masthead in the top image shows a swivel close to coming off the foil and a spinnaker halyard too close to the foil; second image from top, a halyard strap used to keep halyard off the foil; third image from top, spinnaker halyard too close to foil could foul and jam furler; above, an ideal lead-in angle for furling swivel.

Halyard wrap is easily preventable with proper lead in angle and tension. Most masthead sheaves are too high to allow a good feed angle to the swivel, so a halyard restrainer may be needed to keep the halyard lower and away from the top of the foil. It is also critical to have the foils at the correct length to avoid damage to the forestay and fittings. Too long at the top and the foils can damage the top fittings, too short can cause damage to the forestay. All systems are different so you should refer to your installation manual.

Don’t assume your rig is correct just because it was professionally installed, even pros make mistakes. It’s up to every owner to make sure their system is correct. You also need to make sure the sail is a good fit and that the top swivel does not ride up too high on the upper foil. It is important to allow room for some sail stretch as well. If the top swivel comes over the end of the foil it can jam, making it impossible to lower or furl the sail. Make sure your forestay has toggles at both the upper and lower ends to reduce side stress of the wire ends.

Another common problem is poor installation of the furling line itself. Correct lead-in angle to the drum is important if the line is to feed onto the drum correctly. Care needs to be taken that the line does not chafe on anything on its run aft as well. This applies to both jib and main furling units. Chafe can quickly damage a furling line; this can result in the line parting just as the winds are picking up. Keep an eye on this line at sea as well; a line that looked fine at the dock may be chafing when underway. Verify the line used is the correct size as recommended by the manufacturer. An improperly sized line can lead to binding, making it difficult or impossible to turn on the drum. With heavy loads of a reefed sail, the wrong size line can become hopelessly bound in the drum. This also points out that you want to keep proper tension on your furling line while pulling the sail out. Allowing the line to loosely wrap around the drum can cause it to double and bind when pressure is applied.

Bearing types

Salt water and galvanic corrosion can cause problems as well. This is particularly true for offshore and long-range cruisers. Frequent inspections will help catch many of these problems before they become serious issues at sea. Some systems, like Harken, use Torlon bearings that require no lubrication while other systems, such as Profurl, use sealed metal bearings that also require no lubrication. If your system uses Torlon bearings you should never use oil for lubrication as this will damage the bearings. All systems should be flushed with fresh water on a regular basis to rinse out salt.

For cruising boats in the tropics, salt crystals can be a real issue. High salt content water and constant warm temperatures result in salt crystals forming that can easily damage bearings. Galvanic corrosion primarily with fasteners can cause problems as well. Although most manufacturers try to avoid this problem, in the case of fasteners it is hard to completely get around the need for stainless steel screws in aluminum.

The furling line has been led in such a way so that it is chafing on the inside of the block.

Because furling systems do not require the sail be lowered for storage, many voyagers rarely drop their sails. This can make it difficult to spot problems with the foils and joints. A common issue with foils is the joint screws backing out. If the screws back completely out, the foils could separate causing the upper foil to jam the upper stay fitting damaging it and compromising the forestay. They can also pinch the sail luff, preventing the sail from being able to be lowered. If the screws back out just a bit, they can prevent the top swivel from sliding down, once again preventing the sail from being lowered. Both these problems require going aloft with the sail unfurled to fix the problem, not an easy option while at sea.

It is a good idea to drop the sails every few months to inspect the retaining screws in the foils. If loose screws are found, they should be reset using red Loctite. For both jibs and in-mast mainsails, pay particular attention to the web loop at the head of the sail. These loops can be damaged by UV and fail. This will result in the sail possibly coming partway out of the luff groove. For jibs this can cause the swivel to bind and with in-mast mainsails make it impossible to furl or drop the sail.


In-mast and boom furling

In this case, the line is wrapped too loosely on the drum possibly leading to overwraps and binding of the furling line.

Although similar to jib furling systems, in-mast and boom mainsail furlers have some of their own unique problems. As these systems tend to vary in construction and design, it is best to follow manufacturers’ instructions for maintenance. Like jib furlers the biggest enemy will be salt and corrosion.

Both types of systems really need you to remove the sails for a full inspection of the mechanical parts. The biggest issue with in-mast and in-boom systems is jamming of the sail as it is rolled in or out. Sail shape and fit have a lot to do with jamming. It is important to start with a sail that is designed to work with your system. Sails stretch and change shape with age and this can cause problems. The sail will no longer lay flat when rolled and folds will develop that lead to binding. It is important to keep an eye out for this as your sail ages. Wind direction, line tension, and boom angle during operation all affect the performance of these systems. Most systems recommend the sail be rolled in with little or no wind pressure. Keep tension on the outhaul for in-mast and halyard for in-boom as the sail is brought in.

For all systems it is important to be observant while rolling the sail in or out. Watch to make sure it is not binding or getting caught in anything. If it feels like it is hard to operate or is binding, you should stop immediately and find the cause. Applying more pressure will often make matters worse. Check that no other lines or halyards are becoming fouled in the system. This is a common problem and even a flag halyard caught in the sail can jam it. Make sure your control lines are free and not binding within the furler drum. Care needs to be taken when using electric or hydraulic drives and winches as these systems remove the “feel” from the operation and can easily overpower a system and damage a sail or furler. Pay attention to the tension on the furling line and stop if it seems to be getting too tight. If possible, have another crewmember watch the gear and sail while another operates it.

Examples of in-mast furling (top) and in-boom furling (above).

Should a problem develop at sea it can be difficult to repair, but there are some tactics that will help. Try to take your time to look the system over and see if you can find any obvious problems. If the system starts to bind, stop and back it up a bit to see if that clears it. Don’t go back more than a turn or two; if a line is caught in the sail, reversing too far could just pull it in from the other direction.

With jib furlers, should the sail become stuck fully or partially open it is best to turn downwind and ease the sheet to take pressure off the sail. If the sail is fully open, your best option may be to simply drop the sail until you can fix the problem. If the sail is partly furled, but will not go either in or out, there are a couple of things you can do. The easiest is to use a spare halyard to wrap around the stay and sail in spiral fashion to secure the sail until you can make repairs to the furling unit. Another option is to furl the sail either by turning the boat in circles under power while wrapping the sail around the stay or pulling the sheet around the stay to roll the sail up.

For mainsails your best tactic is to turn the boat into the wind to take pressure off the sail. For in-boom furling the sail can then be dropped and secured to the boom. In-mast furlers can be a bit more challenging, working the sail in and out some may free the jam once pressure is off the sail. To get a better pull on the sail, try tying the clew car all the way aft at the end of the boom and pull the sail out with the outhaul while turning the furling drum. If the sail is stuck with the boat headed into the wind, disconnect the outhaul line and attach a free line to the clew, take this line forward around the mast to pull the clew as far forward as possible. Next, turn the boat downwind and try rolling the sail as much as possible by hand starting at the clew. As with a stuck jib, wrap a halyard around the sail and mast pulling the sail to the mast, although you will only be able to secure the sail below the spreaders, this should help control it. Any sail above the spreaders may require going aloft to secure. In rare cases the sail may have to be cut free.

Many voyagers take their furling systems for granted as they normally do not require much in the way of maintenance. For any vessel planning an extended passage, a thorough inspection of all your rigging including the furling systems will help avoid problems at sea. Remove the sails and do a visual inspection of all parts.

Rotate all furlers and note anything that does not feel right. The furler should rotate a full 360° without any hard spots or binding. Inspect furling lines for damage or chafing. Look for loose fasteners; it is not enough to just visually inspect but try tightening each, you should not be able to move any with average pressure. For powered units check all electrical connections and hydraulic fittings. While your sails are down, check their condition and pay close attention to the clew, tack and head fittings. Make sure any shackles used are seized with stainless steel wire. Finally, for jib furlers make sure you inspect the stay ends as well.

Capt. Wayne Canning lives on his Irwin 40 Vayu, in Wilmington N.C. Canning is a marine surveyor, freelance writer, and consultant/project manager on major repairs. Visit and for more info.

By Ocean Navigator