The most intriguing entry this year in the venerable Port Huron-to-Mackinac race, sailed annually over the 235 miles on Lake Huron that separate the port from the island, was a very unvenerable yacht named Dyna. Brand new and relatively untried in deep water racing, Dyna this past weekend proved worthy of all the interest centered on her by polishing off the largest fleet—74 boats—ever entered in the 50-year history of the race, winning class A and finishing first over all in the fleet.
In addition to gratifying her owner and skipper, 47-year-old Clayton Ewing of Green Bay, Wis., Dyna's fine showing proved the success of a complex experiment in materials and design that has been going on since her plans were first drawn. Although outwardly Dyna appears typical of the modern breed of ocean racers—beautiful, fast and extremely complicated—she is anything but typical. Built to a multitude of requirements that take into consideration her owner's comfort, the imperatives of seaworthiness and the involved mathematics of ocean racing handicap rules, Dyna represents a unique solution to problems posed in designing today's intricate sailing yacht.
When Ewing headed Dyna out on Lake Huron last weekend, he was sailing one of the few aluminum hulls ever designed for an ocean racer. Dyna has a minimum of the material traditional in yacht building aboard, most of it in her blond oak interior trim and her plywood decks. To be specific, Dyna's hull is mainly composed of 50-odd transverse ribs of quarter-inch bar aluminum over which are fitted 60 pieces of quarter-inch Alcoa 52 54 magnesium-aluminum plate. (For cutaway drawing of Dyna, turn page.)
The yachtsman's impulse to build in aluminum comes from two sources: first, to be rid forever of the problem of rot (a word that has about the nastiest sound a sailor knows) and, second, to exploit the advantages of lightness and strength inherent in the metal. In the case of Dyna (and one nonracing sister ship), the difference lies in the way in which her aluminum is held together. She is the first all-welded aluminum yacht. Her predecessors are riveted boats, with all the drawbacks of riveted construction, high cost (riveting is twice as expensive as welding), leakage from popped or strained rivets, and hull marred by rivet heads. When Ewing came from 38 miles away to watch workmen at the Burger Boat Co. in Manitowoc swing the plates into place on Dyna's hull and weld them fast, he did so in the full expectation that when she was launched she would cost him little more than a fine wood boat of the same size, would leak not a bead of water and would have a hull as smooth and glistening as the finest mahogany. In these expectations he has been fulfilled.
Ewing himself has been sailing seriously since he bought a 17-foot National One-Design in 1931 on Lake Winnebago. This led to bigger boats, like the 52-foot schooner Ben Bow in which Ewing sailed his first Chicago-Mackinac race in 1942. Ewing soon found the competitive urge that had made him a leading businessman in the pulp and paper field (he sold the Falls Paper and Power Co. in 1951 and has since gone into television) carried over into his sailing. He sold off Ben Bow for the 55-foot yawl Vixen, started to win a few races, took second with her in a Chicago-Mackinac race and took her south in 1953 to the Southern Circuit races in the Caribbean. At various times he had the chance to crew with some of the best skippers in the business—Carleton Mitchell and Woody Pirie among others—to sharpen his racing. In the meantime, he shopped around for a ship to match his increasing skill in the delicate and watchful art of coaxing speed from wind and canvas.
"I wanted a yawl," said Ewing. "If I were going to build a small boat the size of Finisterre [38 feet] I'd build a cutter, but I have to have a bigger boat than that for cruising." Ewing referred to the fact that he and Mrs. Ewing love to sail, as do their two children, Mark, 20, and Marcia, 22. Marcia is married to Howard Tuthill, a sailor out of Grand Rapids, Mich., so there is a crew of five (not including a brand-new grandchild) without half trying.
"From the standpoint of ease of handling, it's much easier to shorten sail on a larger boat with a divided rig, and it's much easier to sail than a single-sticker.
"I also wanted her to be a centerboarder," continued Ewing, "and I didn't want her to leak, because if you get much bilge water in a centerboarder it runs up and creates an unpleasant mess."
With Ewing's dicta in hand, New York's Sparkman and Stephens, the country's leading designers of center-board yawls, ran up a plan and sent it out to H. C. Burger, president of Burger Boat Co., which had done a number of S. and S. designs previously.
"Splendid," said Burger, who had been itching to try a new welding technique on a sailing yacht ever since the combination of Alcoa's alloy (which keeps its strength under intense heat) and the recently perfected Heliarc welding process that makes welded aluminum feasible had been used to build a successful Burger motor launch in 1955.
Dyna was built upside down (standard practice with metal boats), starting with her deck frames at the bottom and building up from there with the transverse ribs forming an arch overhead. In preliminary talks with Spark-man and Stephens, Burger stressed that he wanted plenty of ribbing, closely spaced to give his workmen the rigidity they needed in order to seat the plates and minimize shrinkage and buckling (irreverently called "oil-canning") when the plates were welded. The result was a hull with very few longitudinals—a rather rare thing.
Olin Stephens of S. and S. explained it this way: "Basically, every ship is sort of a latticework of longitudinals and transverses. The spacing depends on how much area you can allow in each of the rectangles of the lattice, and that in turn depends on the strength characteristics of the material you work with.
"Here we have aluminum, very strong, over ribs which are placed rather close together. Thus you can let the whole length of two ribs form parallel sides of the rectangle and the deck and keel form the other two. Of course, the cast-iron keel is a longitudinal which gives backbone to the whole boat. Then, the two beams under the engine also act as strength longitudinals."
In addition to being built upside down, Dyna was built a great deal heavier than she had to be. Since she is an experimental boat, the quarter-inch hull was specified to provide much more safety margin than Dyna theoretically needs. But since ocean racing handicap rules penalize light hulls anyway, Ewing was just as happy to have her that much heavier (Dyna is twice as strong as a wood boat with the same ballast ratio). Ewing was even happier when he found out how much good living he could stuff into Dyna and still keep her weight comparable to that of a conventional sailing yacht.
An added bonus is the fact that Dyna (or any metal ship) saves a lot of space using her hull as the bottom of her fuel and water tanks.
"Finding enough tank space is a real problem on a small yacht," said Olin Stephens. "The owner always wants more capacity than you can give him and still leave a comfortable boat below deck." Dyna has double the fuel capacity and 25% more water storage than the usual yacht her size.
Building in aluminum is not all gravy, however. Although the problem of corrosion is not as serious as on a steel hull, it has to be met. This means that there has to be paint on every square inch of her, starting with a special wash coat and ending three layers later with a finishing coat. In fact, Dyna, with her fiber glass decks and her black, slick hull, has no outward appearance of being anything but wood.
Then there is electrolysis. Technically, this is the chemical reaction between two different metals when immersed near each other in salt water. One metal tends to dissolve and the other to thicken. This proved to be less than fearsome with the aluminum hull. Dyna's rubber stuffing box insulated the Monel propeller shaft from the hull, and the reaction with the cast-iron keel is negligible.
Lastly, care must be taken to keep all the electrical grounds on Dyna's hull at the same potential, or else the offending appliance will be quickly short-circuited.
But these precautions are well worth their extra cost, since they enable Ewing to have what he has been aiming for during his years of sailing: a strong, dry, comfortable hull on a centerboard yawl that is a joy to cruise.
As for racing, Ewing is a bit on the cautious side in predicting what Dyna will do in the future, as befits a man with a new boat ("It takes two years to learn a boat," Ewing said). Before her appearance in the Mackinac, Dyna took a third in her first start (the Queen's Cup race at Milwaukee) and two weeks ago took all the Class A ocean racers in the Muskegon Yacht Club regatta. This is a promising enough start for a brand-new racer.
"Are we proud of Dyna? It's absolutely going to revolutionize the sailing yacht industry," said Burger after the first few race results were in. "If a man wants speed and a light yacht, someday soon he will turn as naturally to aluminum in yachts as he does to aluminum and fiber glass in smaller boats today."
'DYNA': INSIDE AND OUTSIDE
Special aluminum hull was sectioned into 60 pieces, lifted into place on her aluminum ribbing while Dyna was being built. Constructed at Burger Boat Co. in Manitowoc, Wis. in upside-down position, Dyna's quarter-inch hull plates were easily seated in proper spot by workmen. Larger plates all weighed less than 200 pounds, could be handled by simple chain hoist when needed.
FIBERGLAS-COVERED PLYWOOD DECK
-INCH BAR ALUMINUM FRAMES
HOLLOW ALUMINUM MAINMAST
HOLLOW ALUMINUM MIZZENMAST
-INCH ALUMINUM SKIN
HOLLOW ALUMINUM MAIN BOOM
SPRUCE MIZZEN BOOM
WATERTIGHT ALUMINUM BULKHEAD
89-HP G.M. DIESEL ENGINE
18,000-LB. CAST IRON BALLAST KEEL
1-INCH ALUMINUM CENTERBOARD (RETRACTED)
½-INCH ALUMINUM KEEL PLATE
BRONZE PROP MONEL PROP SHAFT
STEM TO STERN
Dyna is a yawl, 57 feet 5 inches over all, 40 feet on the waterline with a 13-foot 7-inch beam and a 5-foot 6½-inch draft (9 feet with centerboard down). She displaces 48,100 pounds (normal for her size), of which the hull, masts and basic fittings weigh only 20,000, allowing Dyna to carry an 18,000-pound ballast keel for stability and pack 10,000 pounds of the good things of cruising life aboard. In her crew's quarters (just aft of the clothes locker in the very bow) is one hinged pipe berth with a head and folding lavatory to port and a hatchway ladder running up the door of the watertight bulkhead which serves to keep the ship afloat in case a bow-on collision ruptures the hull. The forward cabin has two wide, comfortable berths (head on portside not shown) and a large hanging locker aft of starboard berth. Main cabin has four bunks, doubles as dining room with lower bunks as seats. Main cabin bathroom (indicated above on portside with mast passing through one corner) has shower, lavatory, head. Main cabin also has two large hanging lockers, one at each end of the starboard bunks. Galley has double sinks aft and three-burner alcohol stove (not shown) on portside forward of sinks. Icebox and huge refrigerator (drawn in look-through technique) on portside show roominess of boat. Very few yachts under 70 feet have both. Across from galley, chart table sits on top of chart drawers just forward of sail bin. Cockpit (aft of the main hatch) sits over aluminum bulkhead (holes are to reduce weight). Aft in cockpit, wheel and binnacle which encloses the navigating compass are conveniently placed on same pedestal as engine controls. Handles of coffee grinder winch for trimming genoa jib show above deck at stern. Centerboard drops down through slot in cast iron ballast keel (shown in cutaway) and in hollow aluminum keel plate which holds Monel propeller shaft.