J Class Enterprise

Park Avenue is a wide boulevard that runs north-south along the island, a must-see, uncrowded walkway when visiting New York. Its characteristic huge planters with beautiful begonias, give a special look to this exclusive residential artery of New York’s upper classes, full of expensive businesses, luxurious flats, offices and the offices of the most important lawyers. But what on earth do the «begonia planters» have to do with the booms of the J-class sailing ships of the 1930s?

 The J-Class Yacht Enterprise

It was a very special boom, installed for the first time on the American J-class yacht Enterprise, which successfully defended the America’s Cup in 1930, designed by the yacht designer W. Starling Burgess, a 37-metre long steel hull, fixed keel with a 4.50-metre draft, two lifting and lowering centerboards, and a 45-metre-long aluminum meters mast. The gigantic boom, 24 meters long, was 1.2 meters at its widest point with a wide, flat top, so wide that two men could walk along it together, hence its name from the famous fourth avenue. It was equipped with a number of cross rails spaced some 46 centimeters apart along its length.

The Revolutionary Boom

Metal runners (a kind of giant hooks) were sewn along the mainsail’s foot that fitted into these cross rails, and stops, which limited the movement of the runners, were placed in holes in the rails. These stops allowed the foot of the sail to take a smooth curve for better aerodynamic flow as the wind passed from luff to leech of the sail. To quickly identify the best positions in different sailing conditions, each line of holes was painted a different color.

 The Park Avenue Boom

The lines were named after the similarly colored lines on the map of the New York underground system that marked the Seventh Avenue, Times Square Ferry and Lexington Avenue underground lines. So many novelties and new techniques developed at the same time on the Enterprise, it is not clear whether the gigantic cross rail hanger that allowed more or less bag to be given to the lower part of the mainsail was decisive for the speed. However, in 1930, when Shamrock V and Enterprise finally met at Newport, Rhode Island, the two J’s matched well in hull profile, but differed significantly from the deck up.

The Legacy of the Park Avenue Boom

Enterprise’s rig was lighter, had the «intimidating» Park Avenue boom and many winches on board that made maneuvering quicker and easier. Meanwhile, the Shamrock, which sailed the old-fashioned way, had a more traditional, crude counter-steering and rigging system that was more labor-intensive and slow. Enterprise was the winner of the 14th America’s Cup in 1930, humiliating Shamrock 4-0. The Park Avenue boom was also later used on other J-class yachts, including Endeavor, the 1934 America’s Cup challenger. However, this undisputed theoretical advantage has since proved unsuccessful in the sense that it still sails today.

It is only the name and not the supposed aerodynamic advantage that has survived the passage of time to the present day. Curiously, wide booms such as those of the Enterprise are still used today in the «U» or «V» shape and can be walked on comfortably on large yachts where keeping the hundreds of kilos of mainsail folded over the boom is a problem even with muscular crews. Also, fitting a mainsail cover to protect the sail from the weather would be impossible with booms that are two, three or four meters high if they could not be walked on. Lazy jacks can induce the sail but not hold it, the new Park Avenue booms and lazy-jacks make a good team.

In the drawing, the J-Class Enterprise’s sail plan [email protected]