Head Sail Furler Details
Over the years, yachts-men have told about forestays breaking within a short time of having furling gear fitted. Our analysis on this is that there is so much combined weight in the forestay, sail and spar that, when sailing, it creates a big bending moment where the forestay wire exits at the top of the furling spar. As a result of the continuous bending, the forestay wire finally breaks at that point.
To overcome this problem we supply, with Reef-Rite, a forestay swage for the top approximately 3 times longer than a normal swage. This brings the actual start of the forestay wire well down into the spar. The bending moment now occurs on the swage, which is much stronger and capable of withstanding the bend. We believe this may extend forestay life by as much as threefold under roller furling conditions.
Secondly because the furling gear is often fitted on older boats, the age and condition of the rigging is unknown. When the Reef Rite furling system is installed, the headstay is always replaced with a new one as part of the base price.
The Furling Spar
The furling spa is the aluminium extrusion that extends from the drum at the bottom of the forestay to the top of the forestay. The spar must have sufficient torsional stiffness. In laymen’s terms, it should not twist. The spar is fixed at the bottom by a reef line or in the case of a Reef-Rite furler, by a pawl.
Many of the problems associated with roller furlers can be attributed to the design of the spar. Perhaps the worst situation is having the bolt rope of the sail luff pull out of the luff groove and jam part way up. It is then very difficult to get the sail up or down. All Reef-Rite systems have twin oversize luff grooves designed to overcome this problem. An additional advantage of oversized grooves is easier sail hoisting.
Another problem associated with spars is the joints. Most spars are shipped in 2m lengths. On a 9m boat this can mean six joints or more. Typically, at each joint there is some kind of aluminium sleeve inside the spar, extending above and below the joint. The aluminium sleeves are usually fastened to the spar with set screws. The main problem with the joints is that, if the set screws work their way out or if there is any play in the joint because of a loose fitting sleeve, the two sections of spar will work back and forth damaging the sail.
With the Reef-Rite systems, the spar is assembled in 4m sections, thereby halving the number of joints. The spar joiners or sleeves are machined squares. They fit very snugly in the spar and accurately align adjoining sections.
Finally, the spar joiners are fastened to the spar with monel rivets. This is the same type of rivet used on most masts and there is virtually no chance of the rivet coming loose or working its way out.
The Halyard Car
There are two ways to design the halyard car. The first is with open type bearings that can be washed out after all the dirt (at marinas) or salt gets in. The second is with fully protected bearings and seals. Reef-Rite elected to go with the fully sealed bearings for long term maintenance free operation. Our halyard car is constructed of stainless steel with acetal (a very sturdy plastic) spar guides.
The Lower Furling Unit
The most important aspect of the lower furling unit are the bearings. For long term low friction operation the bearings must be high quality and very well sealed. Most units have some type of sealed bearings. The bearing assembly in the lower unit of Reef-Rite has three bearings with two seals at top and bottom of bearings. Other manufacturers have only one bearing and a single seal top and bottom. With this single narrow bearing, the assembly can twist on the vertical axis as the spar moves, opening the seal joints.
Another innovation of the Reef-Rite system is the use of a mechanical pawl. This is similar to the primary winches. The pawl, when engaged, allows the furler to rotate in only one direction. As a result, when a sail is reefed the load is on the pawl and not on the reefing line. The solid locking action of the pawl means improved sailing performance under reefed conditions.
A second benefit is improved safety. With normal furling systems there is a continuous, often heavy, load on the reef line when the headsail is partially reefed. If the reef line becomes loose or breaks the sail is suddenly released. This usually happens when you want it the least. To disengage the pawl a small wire is led aft to the cockpit and controlled by a small lever.
As sails with bolt ropes are lowered, the entire luff is free to catch the wind, blow overboard or simply flog the poor individual who has been talked into bringing the sail down. More often than not the activity resembles a sumo wrestling competition staged on a pitching foredeck more than the controlled exercise it should be. In fact it can be quite dangerous. On top of that, bolt ropes are costly to install and to repair. On many types of spar the groove is so small that a damaged luff tape can’t be repaired. It has to be replaced in its entirety.
With Reef-Rite Reefing systems we incorporate what we call the “Kiwi Slide” and “Downloader”. The Kiwi Slide is a very strong plastic slug that is sewn onto the luff of the headsail at normal jib hank centres. The “Down-loader” gate is a section of spar about as long as the width of your fist. It is situated about waist high on the spar. This short section of spar can be unlocked from the adjoining sections and rotated 90 degrees. This opens the two parallel grooves. The sail is then loaded by sliding each of the “Kiwi Slides” attached to the headsail (starting with the bottom) downward into the section of spar below the gate. When the sail is loaded the gate is closed and locked into place. Attach the halyard car and you’re ready to hoist.
Some of the advantages include:
- Captivated luff – Whether hoisting or lowering a sail, the captivated luff makes the process simpler. The sail won’t go overboard and you won’t have to wrestle it to the deck. In short, it offers control.
- Cost – It is cheaper to change your sails to Kiwi Slides than to change to luff tapes.
- Repairs – Repairs can be made at sea. Kiwi Slides can either be sewn on by hand or tied on through eye-lets in the sail (Kiwi Slides can be supplied with long webbing). Luff tapes usually can’t be repaired at sea.
- Friction – There is less friction when hoisting or lowering sails with Kiwi Slides.
- Double headsail wing on wing It is quite simple to hoist two headsails that have been loaded onto the spar using Kiwi Slides. It is very difficult to hoist two headsails with bolt ropes.