A NEW DIMENSION IN SAILING

The powerful hull at right, surging ahead like a surfboard, is one of an exciting new type of sailing craft called planing boats. Capable of moving at triple the speed of conventional boats, they have advanced the art of sailing into a truly new dimension. Until planing boats were developed (SI, April 28, 1958), the speed of a sailboat was limited by the length of its waterline. Every boat moving through the water made a bow wave and a stern wave (top diagram, right). And once the boat reached a given speed, it could not go any faster, because to do so it would have to climb up its bow wave. Because of weight and the shape of the bottom, the conventional displacement hull could not rise out of its own wave trap. The planing boat, however, is designed to escape the trap. Light in weight, with powerful sails and a flat stern, it behaves like a displacement boat in light winds (center diagram). But when a puff hits, the force of the wind, counter-balanced by the weight of the crew, pushes the boat onto the bow wave. Then the flat bottom, instead of mushing down in the water, forces the light hull toward the surface until it pops out of the trap and skims along (lower diagram) on the crest of its own bow wave. The key man in the development of planing in the U.S. is George O'Day of Marblehead. As a salesman he has distributed more than 900 planing hulls. As a racing skipper he has won the Men's North American championship in a Thistle-class planing boat. Last summer, using the skills he refined in planing, he won an Olympic gold medal in the displacement-type 5.5-meter boats at Naples. At right and on the following pages, O'Day, with the help of his Olympic crewman, Dave Smith, demonstrates these skills both for planing sailors who want to master their high art and for sailors of conventional hulls who can use some of these same advanced techniques to make their own boats go faster.

SPECIAL GEAR FOR PLANING

The 5-0-5 carries all the equipment and has the design characteristics commonly found in planing boats. She has a flat stern to help her get onto a plane. She weighs 280 pounds (compared to 425 for a comparable nonplaning class, the Snipe) and has 150 square feet of sail in her mainsail and jib (a Snipe has 115). Because of her light weight and her big sails, she needs special gear to keep her upright. The most potent piece of equipment is the trapeze (1). This consists of a wire attached to the upper part of the mast, with a wide belt that snaps on at the lower end. In heavy winds the crewman clips the belt to the wire and hangs out over the windward side (above). There he can exert three times the leverage of a man perched on the windward rail. The less spectacular hiking straps (2) are canvas belts under which the legs can be hooked to allow both the skipper and the crew to lean (hike) over the water from the hips up. The extension tiller (3) lets the skipper control the boat while he is hiking. The boom vang (4) is a short wire that holds the mainsail in its best shape. The trap-door bailers (5) are a pair of hinged flaps held by elastic cord (upper diagram, right) that can be released (lower diagram) to drain the fast-moving hull if she ships water.

1 Ready to plane, O'Day and Smith sit on rail. Wind is broadside. Smith holds jib sheet; O'Day holds main-sheet and extension tiller, while he watches for dark patch on water that means strong puff of wind is coming.

2 Wind hits and boat accelerates. Both men move outboard, bringing their ankles up against the hiking straps and leaning out quickly. At same time O'Day slacks mainsheet about a foot, ready to pull it in fast to help pump the boat onto a plane.

3 Breaking onto plane, O'Day pulls sail in quickly, and both men hike far outboard. Boat now surges ahead on top of its own bow wave, leaving typical flat wake as 5-0-5 jumps speed from 5 knots to 10 or more.

TAMING THE TRAPEZE

Trapeze is used only when wind is blowing so hard that hiking with straps, as O'Day and Smith are doing in gentle gusts above, will not keep the hull flat. Crewman, however, wears a wide foam-padded belt continuously, whether it is attached to wire or not. The wire � actually two wires, one on each side of mast � is held secure at lower end by elastic cord. Getting out over water is fast, tricky work. Here O'Day momentarily relinquishes tiller to show proper procedure. First, with belt hooked onto wire, O'Day, jib sheet and wire in right hand, slides back (A) to brace left leg stiffly against trapeze block. Then (B) O'Day pulls jib sheet taut and pushes off with right leg. Next he swings over water (C), keeping left leg stiff, right leg relaxed to act as shock absorber. Coming back in (D), he slips foot under hiking strap before removing belt wire.

GETTING THE BOAT TO PLANE

Getting a boat to plane is fun in any circumstances, but in a race it is absolutely essential, for the first boat up will double the speed of its rivals. Therefore the skipper and his crew must watch the wind and learn to feel when the boat is going almost fast enough. In a 5-0-5 this will be at about 6 knots and requires a wind of at least 10 knots. The instant they feel conditions are right, the men must lean far out, pump the sails and try to bounce the boat out of the trough created by its bow and stern waves and get it up onto a plane.

The most important factor in planing, as in all sailing, is the direction and strength of the wind. A planing boat reacts most efficiently to wind coming in from slightly forward of broadside. Therefore, in the sequence at left and below, O'Day and Smith bring the 5-0-5 broadside to the wind. As a puff hits, they do a precisely timed, simultaneous backward and outward hike to keep the boat on its feet so its broad stern can help lift it up. On a gusty day, when the wind first drops below planing strength and then rises again quickly, the 5-0-5 will go on and off plane repeatedly. The skipper and crew then have to move in and out constantly to keep the hull flat on the water. If they move out too soon, the boat will tip awkwardly to windward, spilling wind from the sails and losing way. And if they move out too late, the boat will miss the chance to get up; or at worst it will flip over, leaving all hands paddling in the water.

STAYING ON A PLANE

Once the boat is on a plane, keeping it there calls for finesse and judgment, especially in maintaining the best, most powerful angle with the wind. As the 5-0-5 accelerates, the direction of the wind experienced on board shifts toward the bow (small arrows in diagram below left), even though the direction of the true wind over the water (heavy arrow below) remains the same. This new and varying wind direction is called the apparent wind and is a combination of the true wind and the air which naturally flows back as the boat moves rapidly forward. If the boat is not handled properly, the apparent wind will eventually swing so far toward the bow that the boat will slow down and drop off its plane. Therefore, as the boat accelerates, O'Day keeps the apparent wind at the correct angle, by driving off (veering downwind). In the diagram, the second and third hulls from the top show how O'Day keeps the apparent wind coming over the side of the hull at a constant angle. As the boat speeds up, both men have to hike out farther. For not only does the apparent wind change direction, but the increasing speed of the boat itself adds to the power of the apparent wind. When the wind drops off, however, O'Day must sense the change immediately and swing the boat back to the original course. The snakelike path that results from driving off and coming back is typical of a well-skippered. planing hull. The enormous advantage of keeping the boat driving at top speed more than makes up for the curving passage through the water.

1 In steady wind, the boat planes perfectly, kept flat by hiking of O'Day and Smith.

2 In rising wind, O'Day drives (veers) off and slacks main. Both hike out farther.

3 Under control, O'Day pumps main to add speed as he continues to drive hull off.

APPARENT WIND shifts forward and then back, forcing boat to drive off and then return to its original course.

RIDING DOWN THE WIND

Three weeks ago on these pages, Olympic Yachting Champion George O'Day introduced the art of planing, in which light, flat-bottomed boats like the 5-0-5 (below) can be made to rise onto the surface of the water and skim along at triple the speed of conventional craft. Now O'Day, with his Olympic crewman Dave Smith, shows how to get even more speed out of a planing hull, first by wave riding and then by setting and handling a spinnaker. These advanced maneuvers are used only in downwind sailing, and require a more sensitive touch than the basic lessons of Part I, where the wind was coming from broadside or slightly ahead.

In the lakes and bays where planing boats usually are sailed, the waves tend to be short and choppy like the ones shown here. Unfortunately, these are the hardest to ride, since they lack power and hence cannot carry the boat any great distance or lift its speed more than three to four mph. Nevertheless, each wave, if ridden properly, can mean a gain of a few yards; and over the full course of a race, these yards can add up to victory. O'Day is particularly skillful at handling a boat in a choppy sea. As each wave approaches, he catches the crest, holds it for a moment, then drops of again, ready for the next one. So quickly do O'Day and Smith manipulate the tiller and sails that the entire sequence shown here takes no more than 10 seconds.
In a larger sea with more carrying power, the jobs of both the skipper and crew are much easier. The sequence can last for half a minute or more; and if the wind is blowing hard enough, a well-balanced boat can hold onto a crest for nearly a quarter of a mile, skidding down the face of the wave at 15 to 20 mph. A planing ride at these speeds is unlike anything else in small-boat racing. A flat wake hisses out astern as the boat surges forward with such steady power that she seems to be riding on steel rails. One false swing of the tiller, however, and this exhilarating charge downwind can come to a sudden, wet halt (see pages 50-51).

1 As a wave approaches from left, O'Day pulls tiller to start stern swinging into crest.

2 With boat's stern toward swell, Smith and O'Day slack sails, get ready to hike out.

3 When crest reaches middle of hull, men pull hard on sails for added speed.

WAVES FROM THE SIDE

The first move in riding waves that come from the side (as shown here) is an abrupt turn to swing the broad stern of the boat into the crest. When the wave hits, the stern rises and the hull gathers speed as it starts to run down the front of the swell. To stay on the wave as long as possible, Smith and O'Day pump the sails in hard, and lean (hike) well out on the windward side, keeping their balance by tucking their toes under the canvas hiking straps, just as they did in the first planing demonstration in Part I.

RIDING WAVES, boat turns 20� off course in order to catch swells.

SHIFTING back and forth in cockpit, crewmen keep weight over peak of wave.

1 Between waves, boat planes along at 10 miles per hour. O'Day and Smith sit quietly in cockpit, ready to let out mainsail.

2 On crest, traveling now at 15 miles per hour, O'Day turns slightly off the wind as both men slide their weight forward.

3 Hanging on as crest starts to leave, O'Day gives 5-0-5 last burst of speed by quickly trimming both mainsail and jib.

4 Back in trough again, both men shift toward the rear of the cockpit as their boat returns to normal planing speed.

WAVES FROM THE STERN

When the swells are coming in from behind, there is no need to make a vio-lent change of course since both the boat and the wave system are going in the same general direction. However, when the first crest moves under the boat, the skipper should turn slightly off course in a gentle, even curve to keep the wind flowing into the sails at the best angle. Veering off like this also prolongs the ride by sending the hull slanting across the face of the wave rather than straight down it. Although the maneuvering of the boat in this situation is comparatively simple, the men aboard must be careful to keep their weight directly over the crest so the boat balances properly throughout the ride. This means they must slide forward and then backward inside the cockpit as the wave surges past. The movements of both crewmen must be smooth and steady, and their timing precise. Otherwise, the boat will wobble down into the trough, losing as much as 50% of its speed, and perhaps the race.

PLANING WITH A SPINNAKER

The spinnaker (right) is a powerful, full-bellied sail set before the mast to give extra speed going with the wind. Sailors of heavy conventional boats use spinnakers on virtually all downwind runs; but planing skippers use them less often for two reasons. First, the sail is so big that it can overpower a sensitive boat like the 5-0-5 when the wind freshens. Second, by tacking (e.g., zigzagging downwind), catching the waves and keeping the boat planing, a skipper like O'Day can often reach the finish line faster using a small jib than he would sailing a straight course under a spinnaker. In light and medium winds, however, O'Day finds that to keep the boat moving he must drop his jib and set the big sail. And in very light air he has to pump the spinnaker (below) to get the 5-0-5 up onto the surface where it can plane.

TECHNIQUE OF SETTING spinnaker is same for planing boat as it is for any small craft (SI, March 2, 1959). When wind strikes, sail spreads out and tends to lift upward. As spinnaker rises, Smith and O'Day pull back on lines, stretching sail so it catches as much air as possible. Going directly before wind (above), men balance boat by sitting on opposite sides of mast, swinging tiller constantly to meet subtle wind shifts, but moving sheets as little as possible to avoid spilling air from sail. When breeze moves decisively to one side, however, crewmen shift to windward (left) and trim spinnaker so that it stays full. Then if boat drops below planing speed, O'Day gets it moving again by pulling back hard on one corner of spinnaker. This quick pumping action gives the sail added lift, in same way small boy gets kite to fly higher by tugging on string.

KNOCKED DOWN by sudden gust, O'Day and Smith are already on high side of hull, ready to climb onto centerboard (below, right).

1 Mast and sail begin to rise out of water as both men put their full weight onto the centerboard.

2 Half recovered from knock-down, O'Day starts back into boat; Smith stays on centerboard.

3 O'Day clambers into cockpit while Smith, still hidden behind hull, continues to pull downward.

4 Once aboard, O'Day moves to far side of cockpit to balance hull while Smith climbs over gunwale.

5 Sails trimmed and bailers open, 5-0-5 drains herself dry as she quickly gets up to planing speed.

SAILING OUT OF A CAPSIZE

No matter how good he is, sooner or later anyone who goes out in a sailboat turns over. But in a planing hull, a capsize does not mean the end of the race. Practically all planing boats have built-in flotation tanks, and since the hulls weigh so little, they float high in the water, even when swamped. If the crewmen learn to move fast enough, they can get their craft upright without dropping too far behind in the fleet. At left, the 5-0-5 has just gone over. As water pours into the cockpit, O'Day and Smith scramble to the high side to keep the mast from going under. Then they quickly pull the boat back on her feet, trim the sails, and by opening the trap-door bailers (below), have the 5-0-5 up and planing less than 30 seconds after she went over. END

□ Souped-up sailers
    Hottest hulls on the Seven-Seas today are the fast and unpredictable planing sailboats
     An article published in Sports Illustrated: April 28th,1958 (PDF document)
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Torgny Nordstrom (to the right) at Baggensfjarden in Stockholm in his first 505 S-1608, "Parbleu"