POSH: much more than a replica of a masterpiece - Soundings Online

POSH: much more than a replica of a masterpiece

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John L. Hacker was a top speedboat designer and builder in the early part of the last century, and he knew a thing or two about planing hulls that many designers today have either forgotten or never knew. The speedboats and commuter craft Hacker created may have been necessity-driven designs, but they were beauties to behold.

Designer Bill Prince has been called on to create a 21st century interpretation of the 52-foot commuter yacht POSH, designed by John L. Hacker in 1937.

There’s no question that long, slender boats are more comfortable at speed, easier and more economical to propel, and have more gentle motions at rest than shorter, wider hulls — assuming that the hull shape, propulsion choice and center of gravity are all on target. And the fact that they are long and low makes them sleek and, therefore, more pleasing to the eye. So why aren’t boats today designed with these proportions?

One answer is simple: Today we can make boats as fat and hard to push as we please, thanks to powerful, lightweight power plants. In fact, the only reason we can get away with building boats that are as much as 35 to 40 percent as wide as they are long is that engines are compact and powerful enough to push them to any speed owners want, as long as they’re happy to pay for the machinery and the fuel.

When boats such as the one that the Huskins Boat Works built, based on a Hacker design, were all the rage in the 1930s, engines were heavy and took up a lot of space. So the best way to get a boat to go fast was to make it easy to push, which meant giving it a long and skinny hull. In those days, if you wanted to go faster than 20 or 25 knots, that’s how you designed them.

Hacker learned a lot about planing hulls when he designed the floats for the Wright Brothers’ plane in 1911, going on to win more than 20 world speed records. But there were also some things he may not have understood — things that modern-day designers such as Bill Prince do understand and are able to correct after a little reverse engineering, thanks in large part to computer-aided design.

As you’ve read here before, good boat design is based on moderation in all things — not too wide or heavy, or too deep-vee or flat aft, and neither too full nor too sharp forward. For a given application, everything should be like Goldilocks’ porridge: just right. On the inside, simple is better than complicated. Complexity leads to problems with reliability, and having too many problems steadily erodes the enjoyment of owning a boat.

In addition to getting the hull proportions and shape right, the most important efficiency factor is weight, and the less the better. There are 60- to 70-foot yachts out there, specifically several convertibles, that have chine immersions aft of well over 1 foot. This points to extreme bottom loading and proves the axiom that you can make a brick plane if you push it hard enough. On the other hand, boats can be too light and too reactive to wave gradients — and uncomfortable as a result.

Bill Prince Yacht Design in Port Washington, Wis., is not one for making bricks plane. The company’s tagline is Naval Architecture + Award Winning Design = Elegant Engineering (www.billprinceyachtdesign.com). I like what Prince has done during his 20-year career as a designer, especially his ability to combine the discipline of an engineer with the eye of an artist. The result has invariably been well-performing boats that look great. You appreciate them equally when watching them from the dock or standing at the wheel maneuvering around the docks or at night offshore.

But although Prince balances art and science, including the science of unbroken arcs of horizon visibility from the helm, others take a much less balanced approach to yacht design. There are many boats out there that look as if they came from the pen of a stylist who has never run a boat, with no consideration given to situational awareness.

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Many of these are impractical and unsafe to be aboard once they cast off from the dock. So it’s marvelous when someone really understands the possibilities of intelligent boat design, who can balance operational capability with gorgeous looks — in other words, highly functional eye candy.

It turns out that these long, narrow boats of the ’30s, with their modest weight spread out over a long bottom, have so much to offer when done right. To pull this off, one needs a talented and aware designer and a customer who understands and appreciates what these old girls had to offer. Such is the case with Prince and his client F. Todd Warner, and the 52-foot commuter yacht known as Posh.

“Posh is a reimagination of a 1930s art-deco commuter yacht but bristling with superyacht tech under the surface,” Prince says. “It’s really something unique.”

With today’s technology, originals can be greatly improved. Why in the world would you play Bach on a harpsichord when the grand piano has been in production for almost 200 years? Rather than build Posh plank-on-frame using mahogany over white oak, as many boats were in those days, it’s a simple matter to fashion her with epoxy cold-molded wood. This creates a far stronger, waterproof, low-maintenance boat that will last indefinitely with reasonable care.

The epoxy bonds the wood planking strips and frames together to create a monocoque structure, with the hull skin doing much of the structural work of supporting the boat longitudinally — to resist wracking — and providing transverse support. Of course, these boats also have stringers and bulkheads for support, but hull skin that is welded together by epoxy reduces the stringer and frame scantlings required, offering both weight and cost savings during construction. In fact, Posh will be built of mahogany to give her the look of the original but with all the advantages of cold-molding.

You could build this boat out of cored fiberglass or even make it plank-on-frame, which adds an authenticity that some people would value more than they would be concerned about the extra maintenance required to keep the boat in good shape. I am as fickle as anyone I know in these matters. A staunch partisan for composites, I lose all my resolve when I see and smell an honestly crafted cedar-over-oak lobster boat. I no longer care a whit about the extra maintenance, which may not be significantly more than it takes to properly maintain a fiberglass boat, by the way. But on balance, the point is that we have so many more and better choices now than we did in John Hacker’s time.

Another bonus with the new Posh is the choice of propulsion, with inboard gasoline power provided by twin V-12, 453-hp Rolls-Royces or V-10, 725-hp Ilmors (good for 60 knots if you don’t profile well as a Type B). Or go with diesels, with a selection of FPT, Volvo or Yanmar power from 435 to 570 hp each. Then there are the electrical, plumbing and mechanical systems that completely outclass those of 80 years ago.

The modern Posh will be 52 feet, with a beam of 10 feet, 9 inches, and a displacement of 20,800 pounds at full load. With all the waterline length and low displacement, she should climb on plane with very little fuss or bow rise. (By comparison, a typical 52-foot by 17-foot, 6-inch production convertible weighs slightly less than 80,000 pounds.) The original version of Posh was built in 1937 for $75,000 — and was featured on the cover of Rudder magazine.

Prince's computer-generated take on the classic commuter

The new boat is largely true to the original, although Prince has tweaked the hull to reduce resistance aft, flattening the buttocks by eliminating rocker and taking the convexity out of the section, which might reduce rolling a bit while cleaning up water flow at speed. Compare the drawing showing the before and after designs (see Page 120), and you’ll see what I’m referring to. The waterlines curving inboard aft indicate the convexity in section (as seen transversely from keel to chine) and in the rocker created aft, which creates negative pressure, raising the bow.

Posh has fore and aft cockpits, with a forepeak cabin in the bow. The saloon is just abaft the forward cockpit and is fully enclosed for those inclement transits. The open bridge has its own large windshield. Nothing makes a boat look so pretty as its length, and this one has it in spades. The raised bridge deck stretches to the aft cockpit, with its U-shaped settee near the stern.

The engines are under the bridge deck, which balances the boat nicely, with the longitudinal center of gravity about 40 percent of the waterline length forward of the transom. The fuel tanks are forward of the engines, below the helm, and centered just forward of the boat’s center of flotation, which happily results in the bow coming up slightly as fuel is burned and speed increases.

The net effect of the engine and fuel tank placement is that LCG is 39 percent forward of the transom, or 61 percent abaft the stem at the waterline, which is perfect for a boat with this one’s speed capability. Hinckley’s tumblehome has nothing on Posh, and there is nary a straight line to be found topside.

Back aft is a U-shaped settee that’s two steps down from the bridge deck. A gate closes off the area, which can be flooded to create a spa tub. Although you don’t want to flood the spa with water in a seaway, there’s plenty of form stability to counter the free surface effect of that spa water at anchor or at the dock. Making this arrangement even more decadent is a hydraulically activated waterproof television that emerges from the deck aft, along with waterproof surround-sound speakers.

Farther aft we have a lazarette deck that slides on tracks for access to the storage space below. Look closely at Posh’s transom, and you’ll see a rectangular outline in the “o” and “s” of her name. This is the aft end of the hydraulic passerelle, lest you think guests would have to exert themselves getting on or off the boat.

Below that, at the boot top, is the outline of the hydraulic swim platform, which projects when it’s needed and tucks away out of sight when it’s not. And that boot top is made of inlaid brushed stainless steel, rather than being painted on in the usual lowbrow way.

If you are fretting that people sitting in the forward cockpit sipping cocktails are neglected, you can relax. A canvas soft top above the forward saloon slides out to cover your head, torso, legs or whatever degree of shade you wish to have. That precise shade angle is then maintained automatically as the boat swings on the hook at anchor, so you can tan the right knee but not the left, or whatever you fancy. And although your tan line is precisely maintained by digitally controlled machinery, you do have to walk to the wine locker abaft the galley to replenish your 1992 Screaming Eagle cabernet because the one thing this boat does not have is a bell with which to summon the butler.

The original and revised lines show the warp in the hull sections reduced for cleaner water flow at speed, reducing drag.

While you are below, your needs have been seen to, as well. For example, the old boats had finely crafted hand cranks to lower and raise the wide windows. With Posh, you just touch the crank, which looks identical to the original “jewelry,” and the window glides up or down with no further input.

I can’t think of another boat that combines the glories of the past with the marvels of the present as this one does. It’s certainly to the manner born (as its owners also will have to be), with a long length/beam ratio, light bottom loading, a clean run aft for low resistance at speed, a sharp waterline forward to tame the chop, and a layout that allows for three or four conversation areas or activities.

You may not be able to fit a king-size berth and his-and-her lockers in the forepeak, but who cares? Posh’s owners will have a boat that, for its size, will take a fraction of the power to push along at 30 knots, while being coddled and pampered by all those amenities and a silky smooth ride. You’re special, like everyone else, but Posh is really special.

Visit www.mahoganybay.net for more about Posh.

See related article:

- If it ain't broke make it 21st century

June 2014 issue