The installation of slugs or slides along the luff of a mainsail with a stop just above the gooseneck can make raising and lowering the sail very quick and easy. No longer is it necessary to feed the sail into the mast slot when raising the sail and, when the sail is lowered, it will not spill out of the slot and flog madly across the deck. There follows some general rules concerning the conversion of a main to slide or slug usage.

First let's clear the way with some definitions. "Slides" refer to the hardware that is matched to external tracks. "Slugs" fit inside a tunnel in the mast -- they can be flat or round. This hardware is usually secured in place with plastic or stainless "shackles" although webbing or twine is sometimes used to sew them in place. Grommets are installed in the way of stainless shackles. The plastic ones are designed to clamp over the sail just behind the boltrope so grommets are optional there. Grommets are often used with twine and webbing but this, too, is an optional practice.

Left: Slide and thimble installed with waxed twine & grommet

Second: Slug installed using sewing machine & webbing

Third: Slug installed with waxed twine using webbing & grommet

Fourth: Slug and shackle & grommet

Right: Stainless bail slug & 5/8” wide plastic shackle (no grommet required)

Begin the installation as close to the head of the sail as possible. Often there will be a slot or hole in the headboard which can be used to secure the slug or slide. If not, install it as close to the bottom of the board as possible.

Then move down the sail in roughly equal jumps of between 26 and 30 inches. If the hardware is installed closer than this, no harm will be done, but the sail will stack rather high above the boom when it is lowered and the reef cringle will also be higher when the sail is dropped to that point. Spacing the slides or slugs farther than 30 inches is seldom desirable since the sail will scallop along the luff unless the halyard is tensioned to compensate.

A “stop” is used just above the window in the mast slot where slugs are inserted or just above the gate in a track where slides are inserted. This stop keeps the sail from coming off the mast when it is lowered. It should be as low as possible to keep the furled sail low on the boom.

It is a good idea not to put a slide or slug within 30 inches or so of the tack. This is especially the case if the sail will be reefed since any hardware below the luff cringle will either have to be removed from the track or slot or the reef at the tack will have to be stacked above the stop in the track or slot. Indeed, this is a good reason for not installing any slides or slugs below the first reef cringle.

On larger boats where the distance to the first reef line may be 5 or more feet, a slide or slug is often installed in this area on a “jackline”. The jackline is a rope that holds the slug or slide close to the luff of the sail when the sail luff is straight but allows it to fall back away from the luff when the sail is lowered. Then the reef cringle can be brought all the way down to the boom without removing intervening slugs or slides.

Jim Grant at Sailrite