Make Your Own Over-the-Boom Riding Sail

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Delighted with the performance of the over-the-boom riding sail, we decided to make our own.

To measure, we outlined the proposed sail area with -inch rope and measurer the resulting edge lengths. The rope ran from starboard stern cleat, over the boom (raised 30 degrees) to the port cleat, and then forward about 75 percent of the length of the boom, and down to the starboard cleat again. The forward corner was secured to the mast with a length of line.

The lines were then lashed together at a point about shoulder high to simulate the clew position, making sure the sheet angle bisected the proposed clew angle. Because each boat behaves differently at anchor, consider using a polyethylene tarp to build a mock-up.

You can reduce the area of a large sail by narrowing the Y or V or lowering the boom, but a smaller sail will be more robust in strong winds. The corners should be reinforced like any jib. Because the riding sail might be used in very strong winds, use storm weight sailcloth and stitch rugged hems that are at least 1.5 to 2 inches wide, or reinforce all edges with webbing. Corner patches must be heavy. All riding sails are cut flat, with no broadseam.

Conventional sail kits are available from Sailrite (www.sailrite.com). When measuring be careful your chosen design it does not interfere with your bimini or dodger and be sure to confirm the forward clew angle.

A note on fabrics. Although polyester (Dacron) sailcloth has coatings that provide UV protection, no sail material is impervious to the sun. Unprotected Dacron will begin to fail within three years of continuous exposure. Top Gun and Sunbrella have more UV resistance, but they stretch-and Sunbrella is vulnerable to chafe. PS is currently researching paints for UV protection of sails, but final results will not be available for several years.

Our provisional suggestion is Amazon Inflatable Paint in gray. For use at anchor we would use the same weight sailcloth as used on the mainsail. For use on a mooring we recommend increasing the fabric weight and painting the sail for UV protection.

Practical Sailor has been independently testing and reporting on marine products for serious sailors for more than 45 years. Supported entirely by subscribers, Practical Sailor accepts no advertising or any form of compensation from manufacturers whose products we test. Testing is carried out by a team of experts from a wide range of fields including marine electronics, marine safety, marine surveying, sailboat rigging, sailmaking, engineering, ocean sailing, sailboat racing, and sailboat construction and design. This diversity of expertise allows us to carry out in-depth, objective evaluation of virtually every product available to serious sailors. Practical Sailor is edited by Darrell Nicholson, a long-time liveaboard sailor and trans-Pacific cruiser with more than three decades of experience as a marine writer, photographer, boat captain, and product tester. Before taking on the editor’s position at Practical Sailor, Darrell was the editor of Offshore magazine, a boating-lifestyle magazine serving the New England area. Darrell has won multiple awards from Boating Writer’s International, including the Monk Farnham award for editorial excellence. He holds a U.S. Coast Guard 100-ton Master license and has worked as a harbor pilot and skippered a variety of commercial charter boats.

1 COMMENT

  1. I misunderstood the design and from Pic #2 I thought the riding sail had a spine between the front triangle and the aft triangles. I had seen a design like that over 10 years ago and figured that was the concept here.

    So I went ahead and made mine like that. It has two aft triangles and one leading triangle. Turned out great even if not the design intended.

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