Ever since man first clamped his knees around a handy log and fled across a river, his boats have been held back by the very stuff that made them possible: water. For water is an ornery element and, while it can provide good solid support for anything floating on its surface, it also provides stubborn resistance to any object trying to push through it.
The obvious way to overcome this drawback is, of course, to get your floating log as far out of the water as possible. In recent years, thanks to lighter and stronger boatbuilding materials, more sophisticated methods of construction and increasingly powerful yet lightweight engines, boats that once nestled deep have been taught to climb up and slide along close to the surface. Planing sailboats, three-point hydroplanes, deep-V ocean racers and many other hulls have found ways to slide free of the sticky molecules and skim along the top. Two distinct types have even managed to lift their hulls completely out of the water and move along in the air just above it. Derisively described as UFOs (Unidentified Flying Objects) by surly traditionalists, these vessels fall into two general classes: the hydrofoils and the hovercraft.
At rest a hydrofoil tends to look and act pretty much like any other powerboat. But once under way its hull lifts clean of the water and flies along on what seem at first to be stilts. Actually, the "stilts" are intricately shaped struts that cut through the water to support the weight of the moving boat much as wings support the weight of a plane moving through the air. Because the thin, streamlined foils are the only part of the boat in contact with the water, friction and drag are reduced to a near minimum.
The idea is not new. Telephone man Alexander Graham Bell was one of the first to experiment with the hydrofoil principle. "If he had had our power plants," says one contemporary hydrofoil maker, "we wouldn't be in business today." But progress was slow until after World War II, and even now, despite fairly widespread industrial and military use, hydrofoils have not had much impact on private boating.
March 11, 1968
Neither have the other UFOs, the hovercraft. Instead of walking on stilts, these nonboats float along on a cushion of air and can perform, if they choose, equally well (or badly) over a beach, a marsh or a city street. More scientifically known as SECs (Surface Effect Craft), they are essentially huge inverted dishes held aloft by a Niagara of cascading air forced downward by ultrapowerful fans through holes in their hulls. As long as the fans keep blowing, a hovercraft will stay aloft a few feet above the surface, but to move forward it needs the push of an airplane propeller or jet.
Like hydrofoils, hovercraft have found wide acceptance industrially, particularly on the other side of the Atlantic. One 165-ton monster just launched in England looks as big as Shea Stadium and can travel at a 60-knot clip. This summer she and a sister ship will begin ferrying up to 800 passengers to and fro across the English Channel on a regular schedule. Other smaller hovercraft buzz about San Francisco Bay and South Vietnam transporting passengers amid whooshing clouds of spray.
For the ordinary sporting boatman, however, both varieties of UFOs have up to now presented too many problems to be practical. Even a veteran powerboat man will plug his ears in horror at the crushing roar generated by a hovercraft's fans and will suffer nightmares at the prospect of guiding one through the maze of a crowded anchorage.
The hydrofoil, on the other hand, can move as quietly as any other powerboat and maneuver just as handily at slow speeds, but because of the paraphernalia hanging down beneath, it must stick to relatively deep waters or run the risk of spearing a sandbar.
There are other hazards as well. One man who hydrofoiled across the Catalina Channel recently claimed he spent most of the trip degaffing some 25 sharks accidentally impaled on his foils. Hydrofoil design is further complicated by the necessity of providing controls sensitive enough to keep the boat "flying" at an even keel.
Despite the obvious drawbacks, however, the prospect of airborne boating for the amateur is just too attractive to abandon. Right now at least two sets of designers are promising to iron out the kinks in each kind of UFO for the weekend boatman. One set consists of famed Ocean Racer-Designer Jim Wynne and his partner, John Gill. Prompted by the enterprising and unpredictable president of the Maritime Boat Co., Merrick Lewis (no mean boatman himself), Wynne and Gill have designed an experimental 20-foot hydrofoil that is more insect than boat. Calling it Maritime Flight I, they claim that this prototype is the first small vehicle specifically designed as a hydrofoil and not as a boat with foils stuck on as an afterthought.
In highly simplified language, Maritime's foils are tipped with tiny wings. Each wing is equipped with a hinged tab—like a wing flap—on its trailing edge. These control the boat's attitude. Aim them down and she lifts; aim them up and she plunges. Like an airplane pilot, the man at Maritime's controls can actually "fly" his boat through the water. He can under some circumstances fly it straight down to Davy Jones's locker, but to reduce the likelihood of this, there are two Fu Manchu whiskers protruding from Maritime's bow that "feel" the oncoming seas before they reach the foils. The whiskers send a message to the wing tabs to compensate for the pitch or roll to come even if the pilot fails to do so. The pilot can override this robot system with his control column whenever he chooses to bank, turn, climb or dive. He steers with rudder pedals linked to a third stiltlike member that houses the rudder. A long stinger of a propeller shaft is coupled to the engine by special flexible joints. This shaft can, if need be, wag up and down without tearing the engine's innards to shards. "Bending power around corners," Wynne calls it.
Unlike most hydrofoils whose appendages hang stiff-legged and unyielding beneath the hull, Maritime's submerged gear can fold up and nest within the hull, thus cutting draft from something like 4'6" to about 2'—a boon when approaching beaches, shallow water or for haul-outs.
So far, Maritime Flight I is only a prototype, but Wynne and Gill are happy with her behavior in "flights" up and down Florida's Biscayne Bay at speeds approaching 40 mph. Does Jim, a two-time champion driver of ocean-racing powerboats, find driving Maritime easy by comparison? "Talk to John," replies Wynne, still baffled by the creature he has spawned. "He flies her much better than I can."
So esoteric in fact is the wooden prototype that neither Wynne nor Gill can guess at its potential. "It's like funny putty," explains Gill. "When General Electric came up with the puttylike silicon, they didn't have the faintest notion of what it would be good for. But look at the stuff now; it's used in everything from the space business to boatbuilding."
While Wynne and Gill were busily building a better hydrofoil, another set of designers, the Anti-Friction Hull Corp. of Severna Park, Md., was hard at work adapting the hovercraft principle to the amateur boatman. The result: a vessel they call the Hydrokeel or, less scientifically, the bubble boat.
Hydrokeels, according to Anti-Friction Vice-President Frank Storke, are not really hovercraft, or even close relatives. They do not fly. Instead they climb up on a big bubble of air trapped beneath their hulls, and slide along on it as happy as a kid on a rubber beach ball. Like the hydrofoil, the Hydrokeel is perfectly at home in the water when it behaves like a normal boat. "You can cruise right along with the rest," says Storke, "until you feel your sporting blood rising. Then you cut in the blower, feel the lift and the surge and leave all the others in your wake."
To achieve these heady goals in their 20-foot prototype Annapolitan, Anti-Friction has built a hull that even they admit looks like nothing so much as a flat-bottomed scow, a vessel hardly guaranteed to inspire speed. But by extending the sides of this barge below the bottom to form solid curtains and by fitting the barn-door bow with special flaps, the designers have managed to trap a cushiony air bubble neatly beneath their boat. When air is forced under the bow by an engine-driven blower, Annapolitan's hull lifts up as if jacked. Once astride this almost frictionless cushion, the Hydrokeel rushes off in a fog of spray propelled by inboard, outboard or stern-drive engines at speeds close to 50 mph.
Such speeds, says Storke, are nothing compared to the rate leviathan bubble boats will travel one day. According to him, full-sized aircraft carriers will not only provide air support but will themselves be supported by air. Landing craft, freighters, ferryboats, anything that floats he envisions sailing on a bubble. Today his company's sights are set on nothing larger than a 46-foot sport-fisherman. "But," says Storke confidently, "there's no question about it, our bubble boats are the ships of the future."
He may or may not be right. Hydrofoil man Jim Wynne, for one, is still convinced a place exists for conventional boats like those he made famous in his racing days—boats able to take the kind of rough weather that would probably rip the foils off a hydrofoil or roll the bubble right out from under a Hydrokeel.