To sailors one of the most beautiful sights in the world is a billowing spinnaker lifted high and drawing well. And one of the most dismal views, particularly from a foredeck, is a collapsed and fluttering chute. Aboard every racing yacht there is a continuing struggle to keep the spinnaker flying high, where it gets the best wind and gives the boat an extra lift. At various times in the struggle the yachtsmen have turned to the sailmakers for help. And the sail-makers have responded with various devices like cross seams or dark colors at the top to absorb the sun's heat and provide a thermal lift.
Now, along comes George Colin Ratsey's new, lifting spinnaker designed full of holes. This rather startling sail, a Ratsey and Lapthorn spinnaker shown here on young Colin Ratsey's yawl Golliwogg, is called the Venturi.
Although the idea for a sail with holes purposely put there is not strictly a new one (Ratsey's uncle Tom put one on an English sloop named Dolly Varden in 1924), Ratsey's successful experiments with the Venturi mark the most radical development in the art of sailmaking since Dacron was introduced right after World War II. More important to the practical racing man, the Venturi, like a number of other apparently wild ideas, may just turn out to be a winner.
Ratsey says he got the idea for his sail from a magazine article that described a crazy kind of backwards French parachute, also made with vents. The parachutist wearing the French oddity stands on solid ground and snaps the chute open. As wind pours through the vents and down the outside of the chute, the currents of air become so strong that the chute rises up, drawing the man right off the ground.
March 5, 1962
Says Ratsey, "I thought if this made a parachute go up, then why shouldn't a sail do the same thing." In an effort to learn more about this lifting principle, he tied a trailer to his car, a sail to the trailer and drove furiously around a deserted Westchester beach parking lot.
After about a month of marking and charting where the wind hit the sails—he tied bits of string all over experimental sails to locate the air patterns—Ratsey produced the Venturi.
As shown in the drawing, the sail has three rows of vents across its top. Each vent is a two-foot slot in the cloth; there are 12 in the top row, and 14 in both the other two rows. The air, when it strikes the back of the sail, flows through the vents and is deflected downward along the front (see lower diagram). Then, according to Ratsey's theory, the laws of physics take over. The law involved here is the one which says that for every action there is an equal, opposite reaction. The air moving down the front of the sail results in an ascending countercurrent above the vents, and the sail rises higher—or so says Ratsey.
Other sailmakers are not yet convinced of this. Ted Hood of Marblehead, for one, says that while a spinnaker with holes should in theory lift well going dead before the wind, there is nothing to say it should work going across the wind on a reach. Hood and some others claim that even if all those holes do provide a consistent lift, they also let an awful lot of air go rushing out when that air would help the boat much more just by pushing forward. And a representative of the Hard sail company believes that in every condition but a run downwind the air will flow uselessly across the sail rather than lifting and pushing.
The pleasant thing about this particular debate is that it will be settled soon, by racing competition. Ratsey says his loft at City Island in New York has already sent some Venturis down to Florida boat owners, and one of them may be used this winter on the southern ocean racing circuit. Certainly before the summer is over Ratsey will know whether he has made a strong case for putting holes in his sails, or, as one critic has been unkind enough to suggest, if he himself has suffered a mild case of holes in the head.