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The Online Magazine For Amateur Boat Builders

The Lateen Rig
Finding a Suitable Use for a Simple Rig
by Chris Wentz
from Small Boat Journal #40 Jan. 1985
drawings by the author

Because the SunFish and its brethren are surely the most numerous type of boat on the water, the lateen rig may be the most widely used rig in the U.S. (No, I don't consider Windsurfers to be boats.) Many builders of series-produced small craft choose this rig for their boats, and a fewyears back the American Canoe Association selected the lateen rig for their Cruising Class.

The reason for this widespread popularity escapes me. The ancient lateen rig was completely passed over by Western seafarers hundreds of years ago, not because it doesn't sail well — it sails very well indeed — but because the rig has vices which render it unsuitable for general use.

click to enlarge
click to enlarge

The problem is twofold: Lateen rigs generate lots of what I call "jibing inertia." The lateen rig has not one, but two very long spars to swing over during a jibe. This moving mass is critical in a small boat, which may not have lots of transverse stability. Also, lateen rigs rarely have a boom vang to limit twist in the sail. A twisted sail creates a rolling force which, combined with a mass of swinging spars, makes jibing, a fundamental sailing maneuver, an invitation to capsize.

The lateen rig is most frequently seen on and is ideally suited to "board boats" such as the Sunfish. They're simple and sporty and have introduced thousands into the sport of sailing. Board boats capsize easily — which helps to keep neophytes from getting into too much trouble — but they are also easily righted and sailed away. For a lateen rigger, self-rescuing ability is definitely a good thing. In a dinghy or canoe, however, a capsize puts you out of action until you drift or get towed ashore.

You certainty can help matters by putting a vang on a lateen rigger, but it's best not to do it exactly as you would on a Bermudian rig. Usually a lateen boom has a small diameter, which will not withstand a point load. And because the boom is so long, it may drag in the water at times, causing it to break at the vang attachment point. One solution is to attach the vang to the boom via a "span" to distribute the load over two attachment points.

An adjustable outhaul would be very useful, but I've never seen one on a lateen rigger. It may be because the ready-made fittings available from many sparmakers have no provision for one. It would be easy to make a wooden end cap with a dumb sheave to fit the aluminum spars.

Most lateen sails are attached to the yard and boom with plastic clips that look like they were borrowed from a shower curtain. Eventually these get old and break. Rather than sail around with missing clips, reeve a spiral lacing line round the boom (or yard). It's far more durable, a lot easier to find, and cheaper. This is one of the few places in a sailboat's rig where you can use nylon line, which can be bought in any hardware store. At least one manufacturer attaches its sail with sleeves. This approach is as durable as the sail itself and is no doubt superior aerodynamically.

Many board boats are rigged by the manufacturer so that the sheet trims to a point along the boat's centerline. This should never be done on any boat with a single sail, because as you pull the boom down to set the leech of the sail, you also pull the sail in too close to the centerline, stalling forward motion. If your boat has a bridle with a loop in the center to attach the sheet to, ignore the loop and tie the sheet onto the bridle with a loose bowline so the sheet can slide from one side of the boat to the other.

Lateen sails are not removed from their spars when the boat is idle. Even so, the sail should not be left out in the elements for storage. Sunlight deteriorates synthetic sailcloth and fades colors. If you wish to keep your sail bent on your lateen rig, either take the spars inside or make up a simple sail cover. Mother Nature's own cotton duck is best for this because it breathes, letting the sail dry. The sail will look better and last longer for it. A light color cover will keep things under it cooler and help prevent mildew.