Appendices -- Useful Supplemental Information

(Published in WoodenBoat #129, March/April 1996. By S.K. Hopkins with illustrations by Dee Carstarphen.)


Twin forestays, sometimes fitted on ocean-voyaging yachts before the advent of dependable wind vanes and autopilots, have all but disappeared. The servo-pendulum and microprocessor upstaged the primitive downwind self-steering derived from jibs on twin forestays. The residual merits of paired forestays were then upstaged by the deceptively elegant roller-furling jib.

There remain, however, cogent arguments in favor of side-by-side headstays:

1) Mast security - giving sloops the staying duplication of the cutter.

2) Convenience. Two jibs remain bent on and bagged. Most foretriangle work can be accomplished without dragging sails back and forth from lockers aft or below.

3) Space. Permanent stowage of a second jib on the foredeck liberates space elsewhere.

4) Downwind speed and directional stability. The moment the wind comes abaft the beam, the second forestay invites a second jib. Set to weather with a pole long enough to place the clew forward of athwartships, this is a surprisingly efficient addition to the sail plan. It fills the jib starved in the lee of the main and counteracts weather helm, reducing rudder angle and drag. Improved directional stability off the wind will allow easier steering or self steering without sacrificing speed by shortening sail aft.

5) Heavy weather safety. The seductive roller-furling jib is often cited as a tool for coping with heavy weather, but some experienced sailors remain suspicious. Roller jibs are compromises between efficient shape and convenience, and the partially-furled jib even more so, in spite of foam padding and other fakery. We’ve all seen yachts limping to windward in heavy weather under these compromises. Failure of the gear to furl can lead to all sorts of bad scenarios. Finally, changing foil-fed sails in heavy weather is tricky at best, and can be very dangerous. Dual jibstays allow a smaller jib to be permanently bent on, to be easily raised as a first step to shorting sail in a rising wind.

Against these advantages must be considered the extra weight and windage of two stays aloft (although this may amount to no more than that of a single roller-furling jib on it’s foil).

Back when twin forestays enjoyed some popularity, one of the system’s perceived drawbacks was that jib hanks could cross over and hang up on the other stay. This tendency is obviated by simply reversing the hanks on selected jibs, and bending on each jib so it’s hanks face away from the neighboring stay. The working jib, for instance, might have it’s hanks open to starboard, and always be set on the starboard stay. The Genoa and storm jib, with hanks opening to port, would always be clipped on the port stay.

If the working jib and whichever other headsail is most likely to be useful are both bent on, a short passage can probably be made before a weather change forces a trip to the sail locker. A boat that cruises through the seasons might keep the working jib and Genoa on the foredeck all summer, but pair the working jib and storm jib during the windy months.

The most elegant use of twin stays is setting a second jib when broad reaching or running. The sail poled out to windward can be the storm jib, working jib, or a small Genoa, while to leeward is a larger sail. Whatever combination, the weather jib will immediately do two important things besides adding to the total sail area: minimize weather helm and deflect wind into the headsail suffering in the wind shadow of the main.

Taken together, the two sails constitute a sort of two-piece spinnaker, either portion of which can be dropped to suit events. If the pole has its own lift (as it should have) the weather “twin” can be dropped in situ when coming to anchor, during a squall, or if it should be necessary to harden up briefly.

A caveat: If not properly engineered, the installation of twin headstays can result in increased compression on the mast. Any system in which slacking one stay induces slackness in its twin will act as a simple purchase. In the best installation either stay can be slacked right off without appreciably affecting the tension of the other. This can be assured by fitting a high-aspect triangular bridle plate which spreads the stays 3-4” at the masthead, and independent attachments at the stemhead. (where a spread of 4-6” should be adequate). To be avoided are wracking or twisting strains such as might be imposed if separate tangs were fitted on the outboard faces of the masthead.

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