Appendices -- Useful Supplemental Information

(From an article published in SAIL magazine, March, 1980. By S. K. Hopkins, photo by Harold Hawley)

THE HALF-WISHBONE MULE

Imagine a modern ketch or yawl setting the equivalent of the old gaff tops’l. Self tending, light weather canvas efficient on all points of sail, up aloft where it can do the most good.

Imagine this “Bermudan tops’l” filling the high-aspect triangle above the backstay and below the triatic.

You have just imagined the wishbone mule, a sail that can help your vessel move faster in winds up to 15 knots or so, ease her roll in a swell, cure lee helm in the lightest airs, and look great while doing it.

Most sailors have never seen or heard of a wishbone mule. Authorities, expectantly consulted, are reticent on the subject. Eric Hiscock, that otherwise impeccable detailer of little ship gear, ignores the mule. So does Donald M. Street’s Ocean Sailing Yacht. (For shame, Don, and you skipper of an engineless yawl that would love a mule.) Wallace Ross’ Sail Power adds insult to the injury of omission by giving the mule’s name away to a kind of Genoa. J. Howard Williams’ comprehensive Sails gives the mule a paragraph, pointing out it is a “useful sail on a close reach” and offers an alternative name: main backstay sail.

In fairness to these authorities I hasten to point out they are describing (or ignoring) a spineless sort of mule that was sheeted loose footed to the mizzen masthead.

Irving Johnson made good use of a boomless candy-striped mule on his canal crawling ketch Yankee -- at least good use for the National Geographic photogs.

When the mule is harnessed to a wishbone spar, it can suddenly:
Be trimmed close hauled when beating.
Be eased right off when running without becoming a useless sack.
Be tacked and jibed without lifting a finger.
Be trimmed without a winch -- the wishbone does half the work.

The wishbone mule’s value is particularly clear when close hauled in light air -- where many two-masted vessels do not shine. The mule adds a long airfoil, with the spill off the mains’l accelerating the flow over it’s lee side. The sail’s heeling effect is large for its area, so the boat gains a little waterline length, gets on her sailing lines, and perhaps generates a bit of weather helm where there was little or none before. The boat comes to life. The bubbles go astern faster.

Reaching, the mule continues to present its most favorable shape to the wind. Running, it is already equipped with a “pole” and shows its whole area to the following breeze.

In the 1930’s there was a short-lived rage for wishbone ketches, which set a “main” through a wishbone pivoted on the mainmast and sheeted to the mizzen truck. These early wishbones were pretty heavy and remained aloft when the sail was handed. Ardor for the type cooled when the big, aptly named Wishbone was dismasted following failure of the wishbone sheet. Gary Hoyt brought wishbones back to respectability with the Freedom 40.

The wishbone makes a good partner for the mule. The sail needs a spar, and the spar needs to be light and handy. The sail’s luff perpendicular (LP) is necessarily short, so the spar is short. Because this is a light-air sail, a half wishbone is sufficient.

Sea Wind, my 30-ft ketch, has carried her mule for hundreds of miles, and the sail has always paid its way. What started out as a novelty has come to be viewed as a necessity, has brightened up many a passage that might have been dull, and more than once given Sea Wind the edge in an impromptu boat-for-boat race.

Sea Wind’s mule has the same area as her mizzen -- about 75 sq ft. It’s miter cut with a wire luff, but no hanks. The 6-foot, 3 lb half-wishbone is laminated of spruce in a graceful curve per standard recipe (max depth 10% of the length at 45% aft). It has a notch at one end (for engaging the backstay, where the spar will pivot) and a couple of holes for tying on the sail.

Setting and striking the sail is a trick -- it is set flying. If the main backstay came to deck, or was belayed within reach up the mizzen, the sail could be set after the jaws of the spar were fixed on the stay, but Sea Wind’s backstay divides at a bridle plate aloft.

There’s a halyard at the main masthead (the spare main halyard), a sheet (the mizzen stays‘l halyard), and a padeye on the mizzen for the tack. The half-wishbone has a light line glued in a hole drilled in the tip of the inside jaw, which will always be to windward when the sail is set. This is called the “twitching line,” and it is critical to getting the notch on the backstay. (Details of “twitching on the mule” are deleted from this abridged version of the SAIL article, but are available to anyone interested. SKH) After “twitching,” halyard tension is increased and the taught luff keeps the spar from unshipping.

Why bother, someone is now asking, with mules and wishbones when you have a perfectly fine mizzen stays’l in the locker? Well, the mizzen stays’l will certainly liven things up if the boat is reaching, but it cannot be carried to windward, and this single fact has caused anguish to more than one skipper. It can’t be carried on a dead run, either, or it will blanket something or be blanketed. And you can’t tack or jibe with a mizzen stays’l -- at least, you’ll be sorry if you try.

In contrast, the wishbone mule is so handy and docile it can be set before the anchor comes up, handed after the anchor is down, and carried amongst ledges, coral heads, lobster-pot floats, or Saturday-afternoon daysailers in between. Just occasionally, you might be able to enter in the log that “She ghosted through the Narrows on a dying breeze, wing and wing and wing and wing.”



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