Apparently not: The Shannon 38 SRD we tested (hull number one) topped out at 20.4 knots, cruised at 18.5, with a pair of 160-hp Yanmar LH-series turbodiesels under the engine hatch. Fuel burn was approximately 11 gph at this speed, according to the boat's Floscan meters; do the math and you'll find the 290-gallon fuel capacity will produce a cruising range of nearly 440 nm, including a 10 percent reserve. Engine options include both single and twin diesel, with conventional or surface-piercing propellers; the surfacing props live under the hull, tucked high in the reverse deadrise. Schulz says that "surface drives are the future," and estimates speed gains and fuel savings of 25 percent over conventional props. (However, the propellers themselves are exotic and costly.) One of the Shannon 38 SRDs currently under construction will have surface-piercing props, so Schulz will soon be proven right, or wrong, empirically.
Why no water-jet drives? Shulz feels that, despite water jets' current popularity, they're not suitable for an offshore powerboat like the Shannon 38 SRD because they're inefficient and, consequently, burn more fuel. The pumps are complicated and therefore costly and difficult to maintain. "I expect owners of the Shannon 38 SRD to go to faraway places.... I also think these places will not be anywhere close to factory-authorized service representatives, so jet power doesn't make any sense."
Once at anchor, or maybe pulled up on a deserted beach, the Shannon offers a cozy home afloat. There are three standard arrangement plans: The test boat had the Plan A layout, with V-berths forward, port and starboard convertible settees with a drop-leaf table in-between, then galley to starboard, head to port. Plan B, suitable only for single-screw boats, steals a bit of space from the galley but adds a double quarter-berth under the pilothouse. Plan C replaces the cabin settees with a convertible dinette to port and a double-berthed cabin to starboard, and adds a separate stall shower to the head. Custom layouts are also available; whichever arrangement you choose, you get Shannon's fine workmanship and a high level of standard equipment.
There's also a choice of six deck configurations. The test boat had the hardtop version, but there's also an extended hardtop, a hardtop with bimini, soft top, flying bridge and flying bridge with extension to shade the cockpit. Each configuration includes wide sidedecks for going forward without acrobatics, teak rails with stainless stanchions, molded nonskid with recessed waterways, a custom pulpit that neatly conceals a stainless Bruce anchor, 14 opening ports with screens and three overhead hatches.
There are two more overhead hatches in the pilothouse, as well as two of the best helm seats I've ever seen: over-stuffed ultrasuede upholstery on rugged, supportive stainless-steel frames, and more comfortable than Barcaloungers. They're just the ticket under way, or for relaxing after a day on the water. Yes, Walter Schulz designed the seats maybe he's been having problems with his back, too
Under way, the Shannon 38 SRD's performance is remarkable. Because the boat doesn't plane the same way as a conventional hull, there's no awkwardness as it climbs over the hump. Instead, it lifts gradually as it accelerates, with just a hint of bow-rise that's easily counteracted by the trim tabs. Consequently, you can run the boat efficiently at any speed, not just either "slow" or "planing" as with a deep-V Once up and running, the SRD hull produces very little wake, indicating a minimum of wasted energy, and punches through waves with no pounding, just like Schulz intended. On the day of our sea trial, Narragansett Bay was showing a two- to three-foot chop, but even at top speed we could hardly feel it as the hull sliced through the whitecaps
The hull is extremely stable in motion, even in beam seas. Yes, as a wave passes under, the hull rolls, then rolls back again, but that's it—no secondary rolling, no ever-decreasing arcs. This is great when boat wakes hit from the beam: You go over a bit one way, back a bit the other, then stop on an even keel, like you're riding on shock absorbers. The same stability allows the SRD to stay level on hard-over turns, with neither the inward heel of a planing hull nor the outward lean of a displacement boat.
Shaping the Future
The Shannon 38 SRD pushes the envelope of boat design with
a radical reverse-deadrise hull
Story by BRAD KOVACH Photos by ONNE VAN DER WAL
A molded "hollow" at the bow water-line throws spray wide and high, which resulted in some drops on the windshield on the blustery day I drove the boat. Astern, however, the wake was bubbly flat, indicating a minimum of wasted energy. The 38 SRD is a remarkably stable platform both at rest and in motion, with little to no lean when turning. "If you can make a cup of coffee and go to the head while under way, it's a sea boat," says Schulz. Mission accomplished.
The inverted-V also tucks the props and rudders up under the stern, enabling the 38 SRD to be enjoyed in shallow water. The hull laminate schedule was specifically engineered with beach landings in mind; it includes a Kevlar/S-glass hybrid that provides extra resistance to abrasion. Incase of grounding on rocks, there's a watertight crash compartment at the nose.
Owners will appreciate the range of available cabin and deck layouts. Three interior arrangements are available, and the cabin can sleep as many as seven people; the head can be ordered with a separate stall shower. The boat I tested had a single forward stateroom with a convertible salon settee, but I also had a chance to walk through a 38 SRD with an additional starboard-side stateroom with a sliding pocket door. Both boats were beautifully finished with mahogany bulwarks and trim, plus teak-and-holly soles. Another plan offers a forward stateroom, mid-cabin and convertible settee.
There are six choices for the exterior: soft top, hardtop (shown), hardtop with bimini, extended hardtop, fly bridge and fly bridge with extended hardtop. High-y lights at the helm include ultra-comfortable Ultrasuede console chair s, plus a drawer-style fridge under the J-companion seat. A teak mast; teak-and-stainless bowrails more than a touch of class, although I'd like to see the rail carried further forward at the nose. Engine access is tight, with a pull-up hatch in the sole and a small step-down compartment under the helm seat. A second, larger hatch aft or a hydraulic system that lifts the entire helm deck are two possible solutions.
Though the boat took four years to design, Schulz says he had the idea in the back of his head for almost 10 years. "I got so crazy toward the end on this project that I never slept," he says. "But, now, driving the boat, I'm happy. It's a real attitude adjuster."
A sharp forward hull section leads to a deep mid-section, but rather than a convex, positive deadrise at the stern which has been the convention since the Phoenicians ruled the waves the 38 SRD employs a concave, reverse dead-rise aft. Schulz, who developed the form over a four-year period using sophisticated CAD software, explains it this way: "Inverting the aft section results in tremendous lift. While the forward section has a deep-V to prevent pounding, the hull shape is then twisted amidships to provide laminar flow that prevents suction at the concave section at the stern. "My motivation was to give my knees a break," Schulz says. "I try to do 1,000 miles a year, so I wanted to end the conundrum of the up-and-down motion produced by most hulls." Add to that the desire to improve speed, range and fuel economy, and to create a shoal draft (24 inches) so the boat can run right up on the beach. "I expect the owners of the Shannon 38 SRD to go to faraway places, not just to go on picnics," Schulz says.
Driving the 38 SRD is a picnic unto itself. With twin 160-hp Yanmars, nearly half the power you'll find aboard many similar-sized planing vessels, we topped out at 20.5 knots. Fuel burn was 11 gph at a cruise speed of 18.6 knots, which means the standard 290 gallons of fuel can yield 440 nautical miles with a 10-percent reserve. Schulz plans to offer subsequent models with surface-piercing props "the future of boating," he says and anticipates additional speed gains and fuel savings of 25 percent over conventional props
Test Power: (2) 160-hp Yanmar LH-serief diesel inboards turning 18" x 16" four| blade Nibral props at a 2.5:1 gear ratiol Power options include single and twirf diesels, and surface-piercing props
Scientists have long held that evolution follows a snail-like pace that is nearly undetectable in the human time frame. But more recently, certain thinkers have proposed the idea of evolutionary "explosions," significant occurrences that can lead to periods of great change. Could the Shannon 38 SRD and its radical hull be a boating industry Big Bang? Only time will tell. But my attitude and my knees have never felt better.
Schulz is a keen fan of the motorsailer concept, especially the variation developed in the 1920s by William Hand, who lived in nearby Fairhaven, Rhode Island. Hand grew up during a time when the Gloucester-style sailboats were being repowered with developing gasoline engine technology. The commercial fishing boat hulls were very efficient and seaworthy, so even the low horsepower of early engine technology proved a huge improvement over sail power.
Seeing firsthand the benefits of motorboats with sailboat-shaped hulls, William Hand went on to become a preeminent designer of motorsailer yachts, drawing and building displacement powerboats that were both fuel efficient and seaworthy, and that used a reduced sail plan for stability, not propulsion. His evolution of work in the 1920s and 1930s show generous displacement and moderate freeboard and proved great sea boats in all conditions.
Coincidentally, Robert Beebe, very much like William Hand, also designed motorboats with sailboat-like hull shapes. Beebe and Hand went downthe same road, but they came from very different reference points: Hand at the turn of the century, Beebe after WWII. While William Hand stabilized a boat with sails and Beebe used paravane systems, both used slippery, efficient sailboat hull shapes.
Walt Schulz knows the limitations of the general motorsailer, notably the lack of livability on all but the largest yachts. Relatively spartan accommodations in a slender hull are a difficult sell compared to beamy trawler yachts, and the buying public hasn't chosen to accept that limitation. Today's couples want their comfort systems, washer/dryer, additional staterooms for guests and lots of space for stuff.
Also working against the motorsailer concept are decades of negative opinions that motorsailers are not really very good at anything, although the success of William Hand's boats would seem to indicate otherwise.
I'm certain that Shannon Yachts could build one terrific motorsailer, with reduced sail plan and ballast for stability, following Hand's lead, and it so happens that the company went ahead and designed one. But the Rhode Island builder has yet to sell such a yacht, and concludes the market just isn't there for a motorsailing cruising boat.
So Walt Schulz has focused on a strict powerboat passagemaker.
The Plot Thickens
When I spoke at length with Walt Schulz on the subject of hull shapes, it was clear that he does not accept the aforementioned compromises of powerboat hull forms as appropriate solutions when one considers a passagemaker capable of circumnavigating. And he insists today's boats are way too complicated.
"I'm up the food chain when it comes to fixing mechanical things," Walt told me, "but today's boats are too much for me. They need to be less complicated. Some of them are downright frightening."
And he couldn't find a hull shape that pleased him in any case. "Basing such a powerboat on a fishing boat makes no sense," Walter explained. "A fishing boat or lobsterboat is designed to run out light, get to the grounds quickly, then run back heavy with its catch. The major benefit of the lobsterboat shape is that weight is infinitely adjustable. It works great, but such dual personality is lost on its use as a yacht. A yacht is always running light. Not to mention, the boat's motion in a seaway can be lively in sloppy seas, to say the least."
I've always thought that if they built a passage-making ocean motorboat, the world would listen.
So I was excited when I learned Shannon Yachts was motoring our way, as I've long been impressed by its boats. Heavy-duty, rugged, impressive and competent are terms that I'd use to describe Shannon yachts of all sizes.
But I was not expecting the surprise that awaited me as I got into a discussion about this project and made my subsequent visit to the Shannon yard in Bristol, Rhode Island. The story of the new Shannon motorboat is one of creative design with futuristic vision.
At first, the Shannon 38 SRD seems to be another variation of the express-style cruiser theme, not really relevant to our cruising under power lifestyle.Perfectly able to offer cruising for short duration, theboat didn't really hit me as a long-distance, liveaboard boat to explore French Polynesia on its own bottom. But I was in for a surprise-and a history lesson.
Designer With A Difference
Walter Schulz is the man behind Shannon Yachts, and he's been building quality yachts since 1975. He is a bearded Irishman whose two grandmothers were born in the lands around the magical Shannon River in Ireland, hence the origin of the company brand. When the first Shannon 38 made its debut at the Annapolis Sailboat show in 1975, Walt took five orders, and the company was on its way. In the 30 years since, Shannon Yachts has launched 335 boats, sail and power, and the company has earned an esteemed position among the ranks of top-quality yacht builders.
Throughout this period, Schulz always wanted to build long-range, offshore motorboats capable of crossing oceans; one strictly as a powerboat, another as a motorsailer. But he sensed an uphill battle on both fronts and chose to keep both projects in the background until it was time. He feels current types of powerboat hull shapes require too many compromises, which would hold him back.
The one-mile-per-gallon threshold of the typical deep-V hull is grossly inefficient in his mind, although its inherent hydrodynamic lift does provide stability under way. He is also convinced that full displacement powerboats roll too much in certain sea conditions, forcing owners to install stabilizer systems to allow for crew comfort. But Walt feels such equipment is overly complicated, not totally reliable, and, in the case of flopperstopper paravanes, even dangerous.
Semi-displacement yachts have flat sections aft to reduce roll but can be horribly snappy, and they too often come equipped with stabilizers. Power catamarans achieve stability under way by having the two hulls some distance apart, but Schuiz thinks the hull form has other issues, notably the pounding and crew-bashing when the seas pick up. It is not for him
February 2005
The Shannon 38 SRD may signal the future
Shannon SRD
by Bill Parlatore
"If someone were to tell me that I'd be in the 21st century and everyone in this business would be marketing hull shapes from the 1960s, I'd laugh in their faces. Everything else in the world has moved forward, even the materials we use. But boat design hasn't changed at all. Underwater, nothing has changed from 1960 to 2004...nothing."Walt has experience on power cats and thinks they are a much better idea than a sailing cat. It's a step forward to him, but they, too, have issues, especially when pounding offshore. And Schulz knows all about pounding offshore, as he makes it a point of spending at least 1,000 miles offshore every year to stay grounded in reality.
A New Direction
Several years ago, one of Shannon's sailboat owners asked the company to build a smaller, second sailboat for sailing shallow Florida waters, and the Shoalsailer 32 was the result. The sailboat draws just 30 inches yet offers great windward sailing ability through a clever hull shape that provides stability through its beam and accelerates laminar flow of water that speeds past the leeward side of the hull and keel.
The success of this shoal draft hull shape led to some interesting subsequent CAD exercises on the computer to see how far it could be taken, perhaps as a motorboat. The effort developed into the Shannon 38 SRD, initially intended to be the powerboat version of this successful shoal draft sailboat. It would be a beachable cruiser.
But the first 38-footer proved to be much more than just another shallow-draft runabout. Indeed, the results of early sea trials of the new Shannon 38 SRD went off the charts, beyond everyone's expectations. The boat has unbelievable fiiel efficiency and outstanding stability at speed. The builder has since become intrigued that this shape might work in a larger vessel intended for much more than beach parties.
In fact, Walt Schulz now wonders if perhaps he is finally working on the holy grail of his career-a long-range passagemaker able to go around the world safely, efficiently, comfortably and with less complexity. Intrigued? Thought so.
Shannon's Patented SRD
SRD stands for Schulz Reverse Deadrise, the design for which is patent pending. I think it best to explain it by walking around the cradled Hull Number 3, under construction at the Shannon yard.
The bow has a hollow entry that draws out into fuller sailboat sections. About 60 percent aft of the bow, the hull shape has a slight hollow formed into each side of the hull to create turbulence, much like vortex generators on aircraft wings. The hollow sections work to keep water from separating from the hull, increasing the laminar flow of water against the hull as long as possible.
Just aft of these hollow sections, the stern twists outward into a wide concave reverse deadrise, looking much like the Klingon Kahless fighter from Star Trek. (No, I'm not a Trekkie, and it took me a few minutes to find the name of that ship on the Internet. But it was the first image in my head when I saw that stern.)
What happens under way is that the slippery, round section of the forward hull does not push water outward as would a traditional powerboat hull, and the hollow midsections keep the water moving along the hull farther aft (again, rather than outward), where it is pushed under the stern, whose concave shape creates enormous lift.
The result is amazing efficiency and stability, opening the door to a major breakthrough in boat design. Ideally, a yacht with such a hull requires less horsepower to reach cruising speed, burns less fiiel and attains stability through hydrodynamic lift.
The first 38 SRD has twin 150hp diesels and has a maximum speed of 25 knots. A traditional deep-V boat would need twice that horsepower to get such speed potential. More importantly to those working on this project, however, is that slowing down to 18 knots, the 38 SRD travels 2 miles per gallon, about half the fuel burn of the "normal" deep-V hull shape.
To Walt Schulz, the target is not top speed, but rather, efficiency. If he can build a boat that cruises at 12 knots with half of the traditional horsepower, the fuel burn goes down as well, allowing for longer range with a given amount of fuel. And a stable ride is achieved through hull shape, not complicated or dangerous roll-reducing gear.
It is this hull shape that Shannon Yachts now offers in a 53-foot passagemaker, taking that first step in the future of long-distance cruising.
A Mighty Fine Day For A Boat Ride
I went aboard the Shannon 38 SRD at the Newport show, while the powerful fury of HurricaneIvan ravaged the waterfront city. The weather that Saturday afternoon was truly ghastly and effectively closed the show for several hours. We were seriously afraid of losing the PMMtent on the docks.
The hull shape becomes active above 6 knots, the water flow interacting with the hull, with its changing underwater surfaces, as if the water is holding onto the hull, refusing to let go. I commented that it felt like a horizontal ice auger pulled along the surface of the water, and Schulz just smiled. I got it.
Later, back at the mooring, we were chatting some about the boat when the wake of a passing launch caused area boats to roll gently as it passed through Newport Harbor. The 38 SRD went through one roll evolution as the wake passed by, then stopped dead.
Despite its express cruiser, retro-style looks, the Shannon 38 SRD is proof of the SRD concept, and is one terrific seaboat. And as it draws only 24 inches, it is still beachable when you're not out conquering hurricane seas.
Each boat is custom tailored to owner needs; there are several accommodation plans and deck layouts to fit almost any requirements. But Shannon Yachts builds each 38-footer with a composite foam core for a high strength-to-weight ratio, and a completed 38 SRD displaces just 13,500 Ibs. And Shannon characteristics for safety are evident, with wide side decks and a secure cockpit. Every Shannon yacht, sail or power, is first and foremost a safe boat.
I spent the night aboard the second boat in Florida, and it was a very pleasant experience. The forward stateroom has a traditional V-berth and storage for extended cruising. Just aft of that cabin is a comfortable dinette on the port side, with a second cabin opposite with a clever, sliding pocket door that really opens up the space when no one needs the privacy of that berthing area.
The galley is complete with all necessary essentials and appears to have more than enough storage for provisions and cooking equipment. A large head is opposite the galley and includes a separate shower. Overall, the boat works for its intended purpose.
The first 38 SRD has twin Yanmar engines and conventional propellers. The second boat has a single Yanmar and also a conventional drive. The third boat, however, is built with a single engine and a surface-piercing propeller.
Normally associated with high-speed racing boats, surface-piercing propellers are 20-30 percent more efficient than traditional propeller drives. With parasitic drag significantly reduced by having no appendages in the water, such drives also allow larger-diameter propellers and avoid cavitation by aerating the blades.
Schulz is experimenting with these exotic drives to see if any of that efficiency can be achieved at slower speeds in an SRD hull, which he feels is well suited for such propulsion drives. The special propeller is located in a prop tunnel inside the concave stern, and the air in the space is energized by exhaust gases and air forced in from baffled vents to "turbocharge" the air hitting the top half of the propeller, which remains out of the water at speed.
Sea trials will prove it one way or the other. More efficiency means less horsepower, which equates to less fuel and a longer range. That is the goal at Shannon Yachts for their new power passagemaker.
Shannon Yachts: The Next Generation
The 53 SRD is the next boat Shannon Yachts will build, using the benefits of the SRD hull form for a long-distance cruising boat. With an estimated range of over 2500 miles at 12 knots and 1000 gallons of fuel, the boat will have the legs to cross any ocean. And its 3-foot shoal draft makes it wonderfully suited for the shallow-water cruising at the other end of the passage
The 53 SRD will be built on a custom basis, with a wide range of layouts and system choices. Initial renderings show a pilothouse and flybridge, a covered aft cockpit, an owner's stateroom amidship with guest cabin forward, and three heads in the boat. The low profile of the boat means bridge clearance will be about 16 feet.
If the 53 SRD performs as well as its smaller sistership, I predict this new passagemaker will be a hit. And without additional complexity so often found on larger trawler yachts, the maintenance of such a boat will ease ownership duties. It's all about the concept of "less is more."
"If I can't use sails, because the market is against it," Walt said, "I'm exploring another direction with the SRD."
The 38 SRD and the larger 53-footer have become personal efforts for a custom yacht builder exploring uncharted waters, quite literally.
We salute Shannon Yachts for pushing the envelope, and we wish them success. We'll stay tuned to its progress. But if you want to experience the future now, I suggest going for a ride on the Shannon 38 SRD.
Even more ink could be devoted to the story of Shannon's Walter Schultz and the genesis of his patented Schultz Reversed Deadrise (SRD) hull design. But lacking that space, the executive summary goes something like this:
Schultz wanted to create a fast, efficient power cruiser that he could run in rough water without punishing his aging knees. From studying the way water interacts with running surfaces at various speeds, he knew that once a boat gets above its displacement hull speed, it expends a lot of energy trying to dig itself out of a hole of its own making.
Most designers solve this problem by simply adding more horsepower. Schultz instead looked for ways to decrease the size of this hole and to make it easier for the boat to dig itself out. Using computermodeling, he engineered a hull form that combined three comfort-making and labor-saving functions: The sharp bow would carve easily into oncoming waves without pounding or pushing water into a wide wake, hollow sections amidships would redirect water flow to reduce suction aft, and the concave stern section would generate ample lift to keep the hull out of the hole.
Anyone wanting more than this simplistic explanation can study the literature — or spend a few minutes with Walter Schultz at most any major boat show. Ultimately, however, any discussion of theory must be put to the test, and this is where the Shannon 38 really sells itself.
To date, Schultz has launched two versions of the 38, and I've been fortunate enough to spend time aboard both. Hull No. 1, fitted with a pair of 160-hp Yanmar diesels, routinely achieves cruising speeds of 18 knots while burning just over 10 gallons per hour. As impressive as it was to compare the fuel flow meter with the GPS readout, the real fun was putting the boat through its paces and discovering that the SRD hull design does more than just boost fuel economy.With a single engine engaged, it tracked straight, turned easily in both
The 38 also proved to be quite an impressive boat in a seaway. Into, across or with the seas, it delivered the knee-friendly ride Schultz hoped for. For a boat with a fine entry and a draft of lessthan 2 feet, it also tracked quite well in following seas and offered the helmsman no surprises.
I later ran hull No. 2, which was fitted with a single 440-hp Yanmar. This configuration boosted top speeds to near 25 knots and provided slightly better than 2 nautical mpg at 18 knots.
Sea trials have proven the validity ofthe 3RD hull form. Market reaction will dictate the success of the overall design. An obvious potential customer is the day-trip or weekend cruiser looking for a reasonably quick, highly economical platform. The amply sized cockpit and swim platform support this mission quite well, and the cabin can be fitted with twin settees that provide maximum flexbility for entertaining, dining and sleep-overs for up to six guests.
An alternate layout, which was shown on hull No. 2, would also be well-suited for more lengthy voyages. It replaces the twin settees with a dinette and a private cabin with a pocket door, and it enlarges the head to include a separate shower.
While those more accustomed to the interior spaces of a trawler or motoryacht might not get it, anyone who has cruised aboard a well-found sailing vessel will consider the 38 more than adequate for extended life aboard. Although it can be fitted with a full range of creature comforts, it is not overly complex. Exactly the type of cruiser I'd want to take down island where the waters can get skinny and the fuel docks and boatyards are few and far between.
