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Main management

Jan 1, 2003

There are several systems to control the mainsail and keep it off the deck when it is being dropped. We will address three systemsbasic lazy jacks and two patented systemsthat can be added to a conventional mast and boom, leaving aside mechanical and powered in-boom and in-mast furling systems. Use of a topping lift or hard vang to support the boom is still necessary with each of these systems.

Lazy jacks are the age-old method of keeping the mainsail under control when it is being lowered. A lazy jack arrangement can be as simple as a few lengths of line running from two attachment points on the mast to two or more locations on the boom. As the sail is lowered, the lazy jacks catch the sail and keep it on the boom. This prevents the sail from cascading down into the cockpit or covering the coachroof.

The Dutchman system employs a continuous-loop topping lift with two or more monofilament lines that run from the topping lift down to the foot of the sail. The monofilament lines pass through vertical rows of nylon fairleads in the main, keeping the sail in line with the boom as it descends. As with a lazy jack system, the Dutchman requires sail cover modifications so the control lines can ascend from the covered sail.

Doyle Sailmakers' StackPack is actually a combination of lazy jacks and a sailcover in one system. The StackPack is not typically retrofitted to an existing sail, but rather a new standard batten or fully battened sail is the building block for the system. When the sail is struck, the sewn-on cover opens to receive the sail, and the lines feed the sail into the cover.

The simplest and least expensive system is lazy jacks. An experienced sailor can design and install a lazy jack system himself, and all the materials are readily available. The system will have two or more legs that will pass under the boom. The trick is to space these legs appropriately along the foot of the sail and to provide a method for adjusting tension on the system.From a point on the mast 2/3 up the luff, hang two lines of equal length attached to eye straps on the port and starboard sides of the mast. These two standing parts will hang halfway to the boom if the system will have two lower legs. We use Dacron double-braid cordage for line. On a 35-foot boat the two upper lines are 3/8-inch diameter, and the boom legs are 5/16-inch diameter. Line diameter can be reduced by using composite cordage. The lazy jacks can then have lower stretch and less visual impact.The lower ends of the two standing parts are finished with spliced eyes and thimbles. Reinforced plastic thimbles work well, though stainless thimbles are okay, too. Without a thimble the legs that will pass through these eyes will not slide easily when adjusting tension. Some systems use blocks at the lower ends of the standing parts. Friction when tensioning or easing the system is thus greatly reduced, but the blocks can chafe the sail if not leathered.Two-legged systemsIn the simplest two-legged system, the legs will actually be one continuous loop of line. A padeye will be mounted on the port side of the boom 20% of the E measurement aft of the gooseneck. Dead end the line on this padeye (a bowline will allow easy seasonal removal). The line will then run up and through the eye of the port standing part, down and under the boom (from port to starboard), up through the eye of the starboard standing part, and down to a cleat mounted on the starboard side of the boom opposite the deadend padeye. The tension of the system is adjusted here.

The aft leg is captured under the boom by an eyestrap. We use a Ronstan Guy Hook instead of a closed eyestrap so that the lazy jacks can be easily unrigged each season. The aft leg will meet the boom about 75% of the E measurement aft. The boom hardware should be located when the sail is on the boom, and moved to accommodate the bulk of the cloth and/or the ends of the battens. A lazy jack that hits the boom just aft of a full-length batten is practically useless.

The number of legs can increase to as many as four depending on the E measurement, but keep in mind the amount of friction at each eye will make it more difficult to tension the system. The friction can be overcome by using blocks instead of just thimbles at the eyes or by making the leg farthest aft adjustable.

In a three-leg system, the standing legs are shortened to 1/3 the distance between the mast-mounted eyestraps and the boom. The forward legs will begin at respective cleats 20% of the E measurement aft of the gooseneck, lead up and through their port and starboard standing part eyes and end in spliced eyes 2/3 of the distance between the mast-mounted eyestraps and the boom. The aft legs are a continuous loop passing under the boom twice and through the spliced eyes of the forward legs. An end-to-end splice forms the continuous loop. The system can now be tensioned at both the port and starboard forward leg cleats.

The lazy jacks should be eased when the sail is hoisted so as to not interfere with sail shape. Care must be taken when raising the sail to stay head to wind to prevent the headboard and battens from fouling in the lazy jacks. If enough length is built into the system, the lazy jacks can be pulled forward to the gooseneck and secured to keep them out of the way when hoisting and sailing. Before dropping the main the lazy jacks should be well tensioned to keep the sail atop the boom.

A modern improvement on traditional lazy jacks was invented by Martinus Van Breems, who devised the Dutchman Sail Flaking System. The system is more sophisticated than simple lazy jacks and is sold through authorized sail lofts who install the required additions to the mainsail. The Dutchman has two or more monofilament lines run through vertical rows of nylon fairleads in the sail. The lines run from attachment tabs on the foot to clamps mounted on a special topping lift. The continuous-loop topping lift is provided to simplify the placement of the control line clamps. The sail simply flakes on the top of the boom and is prevented from spilling on deck by these monofilament lines.

The Dutchman eliminates the problem of the sail fouling on lazy jacks when it is raised because the monofilament control lines are an integral part of the sail (not port and starboard independent lines). There is, reportedly, a danger of a control line catching on a spreader tip when on a broad reach or sailing dead downwind. The positioning of the monofilament line when installed, and a prudent eye aloft, can eliminate this problem.Another approach to controlling a doused main is Doyle Sailmakers' StackPack. It is available exclusively through Doyle sail lofts. The system is more sophisticated and expensive than the options discussed above, but it incorporates the additional feature of a custom sail cover. Simple lazy-jack systems and the Dutchman both require either new or altered sail covers to accommodate their control lines.

The StackPack consists of a sail cover containing two battens that shape it to receive the mainsail for stowage. Lazy jacks are integrated into this cover and run up to the mast in similar fashion to a basic lazy-jack arrangement. When under sail the cover is held flat against the foot of the main. The sail can be reefed or fully lowered into the cover. When fully lowered the cover zips shut above the sail, and a forward piece encloses the luff and mast.

These three systems are the most successful mainsail handlers. From the simplest to the most elaborate, each can be installed on a conventional mast and boom to make dousing the main more manageable. A sailmaker is required for either the Dutchman or the StackPack, and the help of an experienced sailmaker or rigger will ensure the design and installation of a lazy-jack system goes smoothly.


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