Rovings August/September Issue 150

from Professional BoatBuilder magazine No. 150
Compiled by Dan Spurr

Glen-L Passes 60

Glen-L MarineGlen-L Marine

Glen-L Marine’s 17′ (5.2m) Sea Knight was featured in the May 1957 Popular Mechanics Magazine, thanks to its West Coast editor. Such stories were instrumental in the company’s success.

Since its inception in 1953, Glen-L Marine has probably put as many people on the water as any single company has—excepting Grumman with its ubiquitous aluminum canoe, perhaps. Before the fiberglass revolution, the most affordable way to own a boat was to build it yourself. And thanks to the development of plywood as a structural building material during and following World War II, Glen-L capitalized on plywood’s attractive properties and price by drawing plans for all sorts of boats, from small fishing boats to runabouts and cruisers. Articles published in Popular Mechanics Magazine captured the imagination of young and not-so-young men everywhere determined to pilot their own mini-hydroplane or ski boat. Indeed, the company regularly hears from customers whose first boatbuilding experience was a father-son project way back when—a life-changing experience for many.

Catalog of plansGlen-L Marine

A Glen-L catalog of plans with boat designs ranging from runabouts to multihull sailboats. Today, the company offers more than 300 designs.

A recent spate of deaths reported in this column prompted me to inquire about Glen L. Witt, the founder of Glen-L Marine and longtime designer and seller of boat plans for amateur construction. It would be nice, I thought, to write about an old-timer in this business before he died.

The company is now run by Witt’s daughter Gayle Brantuk, who grew up in the business, and now sees her main responsibility as marketing. For one, she and husband John have done a nice job with the website. When I recently called to chat, I was surprised to hear Gayle say that Glen comes into the office every day for a few hours and that he was in fact sitting right next to her—and would I like to say hello.

You bet!

After exchanging pleasantries, I asked, “How old are you?”

“Ninety-five,” he said. “This was never work for me. I enjoyed it.”

After World War II, Witt was in the foundry business and eventually owned a piece of the company he worked for. “I had an income and nothing to do,” he said. As a 12-year-old he’d built “three-point hydros” and had always had a love of small boats. So in the ’50s he enrolled in what was then called the Westlawn School of Yacht Design. Still the company’s mission, his goal then was to enable people to build their own boats affordably and easily, and to provide the necessary assurance and guidance so that the result of their labors is a good product.

Glen L. Witt

In the early 1950s, Glen L. Witt studied boat design at the Westlawn School of Yacht Design to pursue his love of small boats.

Ken Hankinson and Glen WittGlen-L Marine (Both)

Prominent small-boat designer Ken Hankinson (seated) worked for Witt (standing) for 22 years before going out on his own. When he retired, Witt’s daughter Gayle Brantuk, who now runs the company, bought his inventory of plans.

“Plywood was just beginning,” Witt said. “We could get lengths up to 20′ [6.1m]. Good stuff. Mostly Douglas-fir imports.”

We talked about the American Plywood Association, comprising mainly a group of mills, and the boat plans it circulated “almost free” to encourage purchase of its products. But without customer support, Witt said many of those boats could “come apart in the fog.”

Believing that lofting lines from small-scale plans onto a shop floor was a skill beyond the means of most would-be home builders, Witt decided early on to offer only full-size plans. (And for years he also offered kits of pre-cut parts, but no longer.)

In the beginning, Witt worked in the back bedroom of his home, but as orders increased, he rented a storefront and hired a secretary to whom he dictated all his customer correspondence. Those were the days when you wrote a letter to the builder or designer asking questions and hoping for a brochure; in return you got a typed letter with answers that required time and thought.

Until he could afford his own blueprint machine to make copies of plans, they were sent out to a blueprinter. Later, shelves were built to stock plans, which were printed every day to keep up with demand.

Many readers will recall seeing Glen-L Marine boats on the cover of Popular Mechanics Magazine. That godsend happened four or five times, Witt remembered. Inside was a feature story on one of Witt’s designs and contact information for the catalog “How to Build 20 Boats.”

“It put us on the map,” Witt said, “though I still can’t figure out how we got in.” Credit goes to the magazine’s Pacific Coast editor, Tom Stimson, who took a liking to Witt and his business.

Asked how he chose the designs—if he did any marketing studies to find out what sorts of boats were most popular—he said, “I was an independent old bastard. I built more than 50 boats. Many of those were used for plans. But it depended on my mood. There was some reasoning going on, but no science. I designed classic boats. All styles. There aren’t many holes to fill.”

For 22 years, Ken Hankinson designed boats for Glen-L Marine before going out on his own in 1987, operating as Hankinson Associates. When he retired a few years ago, Gayle Brantuk bought his inventory of plans, bringing Glen-L Marine’s inventory to 300-plus plans, ranging from cabin cruisers to sailboats, and dinghies to the same hydroplanes that captured Witt’s imagination in the 1920s and ’30s.

Replica of a pre-war mahogany runaboutGlen-L Marine

While nearly all Glen-L Marine customers are amateurs, many have achieved professional-quality results, such as this replica of a pre-war mahogany runabout à la Chris-Craft and GarWood.

Talking with Witt this day, he said he’d just finished a design but he needed someone else to work on it because “it has too many flaws.” It’s for his grandchildren: “Kids’ boats. They have a pond. What I do is geared to what they would like.” Completing that thought, Gayle said she recently bought paddleboard plans from a local company “to get younger kids involved,” because “most of our clients are middle-aged.”

Witt began turning the company over to his daughter Gayle and son Barry in 1996. Barry Witt was involved for some years but retired seven years ago.

After Glen’s two hours in the office are up at noon every day, he and Gayle have lunch. They’re close. And she feels strongly about preserving his legacy. “Dad started the company because he loved boats and there were no plans available for regular guys. He wanted to offer plans and instructions with all the details to walk someone through his first boat. Building a boat has changed people’s lives.” Indeed, many of Glen-L’s customers have been fathers and grandfathers building a boat with their children or grandchildren, sharing an experience that bonds them for life. That’s Glen Witt’s legacy.

Glen-L Marine Designs, 9152 Rosecrans, Bell­flower, CA 90706 USA, tel. 562–630–6258, fax 562–630-6280, website


New From Robert Perry Yacht Design and Pacific Seacraft

Pacific Seacraft Corp. was founded in the mid-1970s by Henry Mohrschladt and Michael Howarth. Based in Fullerton, California, the company built cruising sailboats, most to the design of Bill Crealock, who died in 2009. After 13 years in business, the company had one of its boats named on Fortune magazine’s list of America’s Top 100 products—a rather unusual award for a boatbuilder. The partners sold the company in 1988. Jump ahead to 2007 when the owners filed for protection under Chapter 11 bankruptcy laws. And enter Stephen Brodie, a marine archaeologist, who was looking for a business to run. He bought the assets at auction—some tooling and a half-dozen incomplete boats—and moved everything to Washington, North Carolina.

Robert Perry Yacht Design
At 61′ (18.6m) on deck, Catari is the largest build ever undertaken by Pacific Seacraft; with this custom project the yard hopes to interest other customers in the hull. The two cockpits—aft and center—plus the ketch rig presented designer Robert Perry with an unusual set of challenges.

Brodie says that today, “we have tooling for a 31, 32 pilothouse, 34, 37, 40, 40 pilothouse, 44, 61 [9.4m, 9.8m, 10.4m, 11.3m, 12.2m, 13.4m, 18.6m], and a 38 [11.6m] fast trawler. A big portion of our business over the last five years has been refit and restoration of existing Pacific Seacraft boats. We have had boats steadily coming through from all over the world. The boats have always been very well built, so they are worth the investment to keep up and upgrade.”

He says most work—metal, wood, upholstery—is performed in-house. “We have a crew that is very flexible with multiple skill sets,” he says.

Equipping the shop required a “fairly substantial investment,” he says; significant was a new mold shop air-handling system.

And then there was the tooling for the new Robert Perry–designed 61, a major undertaking.

Here’s Perry’s description of the project:

Catari, named after the famous opera aria, was designed and built for an Annapolis client who wanted a cruising boat capable of good performance offshore with an uncommon amount of comfort below and on deck. Probably the most unusual feature of the design is the deck. In the early stages of the preliminary design my client had a hard time balancing the advantages of an aft cockpit layout against the advantages of a center cockpit layout. I suggested that we go with both, center cockpit and aft cockpit. This created a very complex deck layout compounded by the additional gear required by the ketch rig.

Checking the keel-bolt spacingsBill Kund Photography

Catari’s keel was poured at MarsKeel in Canada and trucked to Wash­ington, North Carolina; here a technician carefully measures the keelbolt spacings.

“The hull is moderate in its proportions but a bit on the narrow side with an L/B [length/beam ratio] of 4.06. I prefer narrow boats for their more benign handling characteristics. Draft was analyzed with several VPP studies, and we finally settled on 7′ [2.1m] draft with a long, moderately low-aspect-ratio fin with a bulb tip. Although this is purely a cruising boat, I did everything I could to make certain the performance will bring a smile to my client.

“From day one my client wanted a ketch. I tried to talk him out of it, but I failed. In the end he just likes the look of a ketch. But in this case the ketch rig has a real advantage for us. There was a bridge clearance issue, and this meant a relatively short rig. Using the ketch rig with a large mizzen and a short bowsprit I was able to get the sail area I needed while keeping mast height reduced. The all-carbon rig will be built by Offshore Spars [Chesterfield, Michigan].

“This deck layout was a bear. Two cockpits and a ‘pilothouse’ complicated things. I enlisted the help of my buddy Tim O’Connell from Vancouver to help me sort out the deck, and now, after several trips to the yard and a lot of computer time, I think we have a good working deck layout. Spinnaker gear will be handled from the center cockpit. Sheets will be handled from the aft cockpit. The “pilothouse” extends aft to cover the forward portion of the cockpit for shelter. There is a fold-down swim step flush in the transom.

“The interior features an owner’s suite aft. There is a workshop adjacent to the engineroom that can turn into an additional single-berth stateroom. The galley was the primary focus of the main cabin. My client loves to cook. Forward there is a large head and another double stateroom. The pilothouse is really just a raised area so that when you are standing on the first step/platform of the aft companionway you will have a 360° view. The interior finish style is very traditional with paneled bulkheads.

“Pacific Seacraft in North Carolina has been wonderful to work with on this big project. I have thoroughly enjoyed my times at the yard. They are doing a very nice job.”

Ivan Erdevicki, who worked with Perry for a time and has been on his own for some years, did the engineering.

Here’s Brodie on the build:

“All of the construction details focused first on safety, stability, and ruggedness, and then on weight. The hull is DIAB Divinycell cored with a very robust H-360 foam core grid system wrapped in over 0.75″ [19mm] of glass. High-temp core was used above the waterline, as surface temperatures on the black Awlgrip hull in the tropics could be extreme.

“There is a solid fiberglass spine about 4′ [1.2m] wide down the centerline that is over 2″ [51mm] thick. This solid fiberglass continues in to the deep keel sump, which carries a 16,000-lb [7,248-kg] lead keel built by MarsKeel [Bur­lington, Ontario, Canada]. The keel is bolted to the keel stub with nineteen 1.25″ [318mm] Aqualoy bolts. Full 3/8″ [9.5mm] stainless backing plates line the bottom of the sump between floors and spread the load very evenly over this robust structure.

“There is also a Kevlar laminate incorporated in the hull inner skin for tensile strength and impact resistance. For­ward is a heavy, infused, watertight bulkhead with the for­ward locker accessed from the deck by a beautiful flush Freeman Marine hatch. Most of the fiberglass in the hull is hand laid with vacuum-bagged core. Structural cored bulkheads were resin infused. Vinylester resin was used throughout.

“The hull-to-deck joint is a fully glassed box-frame structure forming a 6″ [1.8m] perimeter bulwark, which adds safety and lateral strength along the sheer. The deck is also Divinycell cored with solid glass sections for hardware and chainplate placements.”

It’s heartening to see a good name like Pacific Seacraft not only resurrected but also taking on ambitious projects like this.

Principal specifications: LOA 65′4″ (19.9m), DWL 49′2″ (15m), beam 15′ (4.6m), draft 7′ (2.1m), displacement 50,000 lbs. (22,650 kg), auxiliary 135 hp (101 kW).

Pacific Seacraft, P.O. Box 189, Washington, NC 27889 USA, tel. 252–948–1421, fax 252–948–1422, website

Robert Perry Yacht Design, 11530 Tulare Way West, Tulalip, WA 98271 USA, tel. 360–652–7771, website


Speed Endured, Speed Considered

An aluminum Vector 28Claes Axstål

An aluminum Vector 28 (8.5m) built by Swedish builder Vector ProBoat is put through its paces in a test of seakeeping ability as part of the High Speed Boat Operations (HSBO) Forum in Gothenburg, Sweden, in May.

Most boat shows are about boats, and most academic conferences are about, well, academics. The biannual High Speed Boat Operations forum (HSBO) hosted by Swedish shock-dampening seat manufacturer Ullman Dynamics in Gothenburg, Sweden, is a rare and unlikely combination of the two that marries a dock full of high-performance professional-grade small craft—from rescue boats to coastal military operations and transport—with a convention hotel and lecture theater full of naval architects, professional boat operators, special forces and coast guard commanders from multiple countries, medical researchers, boatbuilders, propulsion experts, and components manufacturers.

As its name suggests, the latest four-day forum (May 6–9) was tightly focused on speed at sea, but not the thrill-seeking or testosterone-driven high-speed runs of recreational boaters. The majority of the 300-plus delegates know firsthand about the grinding, long offshore hours required of search-and-rescue crews and military forces who must run small craft at speed in often harsh sea conditions. And that means they thoughtfully and seriously discuss seakeeping, risks, pain, and regulations far more than they gossip about top speeds and record-setting passages. What follows are just a few high points of this well-run event.

In his opening keynote address, Ed Veen, director of the Dutch Coast Guard, articulated his complex love-hate relationship with high-speed boats: Most of the accidents and law enforcement actions his crews respond to involve high-speed boats; at the same time, the most efficient coast guard response vehicle is a high-speed boat of its own. The challenge comes in keeping the rescuers/enforcers safe while operating day after day in often extreme conditions. His conflicting emotions were common among professionals at the conference.

“Faster, harder, farther, and longer are becoming the norm,” said retired Royal Marine and marine consultant Bob MacDonald, who specializes in working with government agencies and special forces on small-craft operations. MacDonald noted that with these trends and the increased capabilities of specialized vessels to run in extreme conditions, the crew are rapidly becoming the point of failure. They are where we need to focus. He called for an integrated approach to design of operator-and-passenger workspaces at a level equal to that invested in hull design. After all, “the boat without the people in it is nothing more than a platform,” he said.

In spite of his crew-centric approach to high-speed boat design, MacDonald was critical of European Union’s 2002 directive that limits exposure of crew and paying passengers to whole-body vibrations (note that the directive does not apply to recreational boats).

“Not a single fast boat can comply with these regulations,” Veen agreed. And as a practical workaround, exemptions from the directive are granted by individual member countries on the condition that best available technologies are applied onboard to minimize shock exposure.

“Poor legislation is not respected and not enforced,” MacDonald warned.

Duke University researcher Dr. Cameron Bass, who has been studying ways to predict human injury risks in high-speed boats for 20 years, called the 4-g threshold in ISO 2631-5 “way too low,” especially when the actual impacts on the spines of high-speed boat operators can frequently reach 14 g to 16 g. He stressed the importance of calculating and recording the magnitude and the frequency of high impacts as boat operators conduct missions over time. In short, while 5 g may not be as bad as 10 g, its greater frequency can make the lower value a greater risk over time.

Dr. Johan UllmanAaron Porter

HSBO host Dr. Johan Ullman demonstrates the motion and compaction of the human spine when exposed to extreme vertical accelerations from the slamming of high-speed boats operating in rough seas.

That reality points to the need for comprehensive health-monitoring programs for high-speed operators, an example of which was provided by Richard Finnemore of the U.K. Ministry of Defense, who explained his office’s comprehensive approach to monitoring and tallying sailors’ accumulated career exposure to slamming impacts.

The regulatory subject was summed up by host Johan Ullman and MacDonald in separate calls for the drafting and implementation of clear and measurable standards for impact exposure assessment (see “Slamming Standards,” Professional BoatBuilder No. 149).

Presenters from the design side outlined numerous efforts to maximize seakeeping and minimize impact exposure for boat crews. Jeffrey Bowles of Donald L. Blount Associates delivered a practical overview of a naval architect’s considerations in maximizing seakeeping abilities in high-speed boats to protect a vessel, its cargo, and its operators. While how a boat is driven affects ride quality, he insisted that boat geometry is the primary influence, adding that vertical accelerations are extremely difficult to predict. He presented applications of Savitsky and Hoggard-Jones equations to determine theoretical accelerations at the center of gravity (CG) and bow of a boat to stay within exposure limits specified in a design brief.

Then he explored applications of computational fluid dynamics (CFD), finite element analysis (FEA), and tank-testing of models in a range of loading conditions, speeds, and sea states. His basic list of characteristics to maximize seakeeping ability: less than 20° deadrise, bell-shaped bottom sections, and a rounded keel section.

Andrew Lea and George Robson of Abu Dhabi MAR detailed their use of the same tools through the design-and-prototyping process with all the specifics allowable for a still-classified 60′ (18.3m) assault and special operations vessel tailored for high-speed service in rough sea conditions. Their CFD analysis revealed stress points in the hull during operation. In addition, they ran thorough FEA including all elements of the laminate schedule, fiber orientation, tapers, etc. for slamming, grounding, and crash-situation analysis with fine-mesh studies of dynamic areas such as rudders and hatches. In an additional design step that followed extensive model tank-testing, they built a 32.8′ (10m) manned prototype to confirm the performance of the innovative hull shape before investing in a full-scale model.

HSBO fleetCourtesy Jaako Pitkäjärvi

Some of the assembled HSBO fleet available for testing. In the foreground is the Hysucat, a hydrofoil-supported catamaran from Hysucat Marine, in South Africa.

Japp Gelling of Damen Shipyards (Gorinchem, The Netherlands) traced development of the axe bow concept, a 1990s creation of Dr. Lex Keuning at TU Delft, The Netherlands, recalling that the narrow high-bow hullform was inspired by Keuning’s own knee injuries sustained during testing of 98.4′ (30m) crew boats in the North Sea. Upon looking into vessel performance, Keuning found that 85% of speed reductions were due to crew trying to avoid peak accelerations, because humans respond to peaks not averages. In response, he explored the enlarged ship concept, which increased length but not beam for better seakeeping. Gelling said that concept evolved into the more extreme axe bow concept with the goal of a 50m (154′) boat capable of operating at 55 knots 365 days a year in the North Sea. Since then, Damen Shipyards has built multiple models, from large supply and patrol boats to an axe-bow catamaran crew boat. He cited reductions in vertical accelerations from 10 g in conventional high-speed crew boat hulls to 1.3 g on axe bow models.

Gerard Kutt of HWAC Technologies (Hong Kong) advocated a smaller-scale design solution to improved seakeeping: the hydrofoil-supported catamaran concept, known as the Hysucat. Briefly stated, a fixed foil between the asymmetrical hulls of the catamaran delivers passive ride control for this hullform. (For more on Hysucat design, see PBB No. 124, page 14.) I confess that the performance of a dihedral foil dipping in and out of the water at planing speeds is not as easy to envisage as, say, the axe bow, but that’s where the in-water component of HSBO shines. Two Hysucat variations were available for testing, and they confirmed performance for any skeptics.

The fleet of nearly two dozen vessels for testing ranged from the venerable CB90 and the new axe-bow NH 1816 model rescue boat from Damen, to the practical C-RIB Police Rescue model patrol boat, a very fast and stable rough-water rescue prototype from Norsafe, an aluminum Vector 28 (8.5m) with an elastically mounted wheelhouse, and a versatile military-grade RIB from Boomeranger Boats.

The final day of the forum was devoted to a series of in-depth tutorials on specific design and safety subjects that we haven’t the space to explore here, but some of which will undoubtedly show up in the pages of PBB in the coming year.

For more information about HSBO, visit

—Aaron Porter

Natural Ventilation

Christ-Craft sunroofWebasto

Chris-Craft installed its first sunroof on a Corsair 36 Hard Top (11m) last year—a Series 60, supplied by Webasto.

Sunroofs in automobiles have been around a long time as a less expensive alternative to the convertible or air-conditioning to allow fresh air into the interior and to exhaust smoke and odors. Early units were manually operated; today, electric motors open, close, tilt, and lock the window. While marine adaptations of this technology have been customized for larger yachts for many years, they now are becoming more readily available for smaller boats as well. Webasto, the German maker of heating and cooling systems, has for a few years been offering several series of sunroofs.

Smallest of the line are the Series 20 and 40 lightweight, manually operated panels. The Series 20, introduced two years ago, is made of 8mm (1/3″) tempered safety glass and fits an opening 44.5″ x 39.5″ (1,130mm x 1,003mm).

Last year, Webasto supplied Chris-Craft with the boatbuilder’s first sunroof, installed on a Corsair 36 Hard Top (11m). The Series 60 may be top or flush mounted, ordered in various sizes with custom curvature, made with glass or PMMA/acrylic lenses, and framed with anodized, coated, or colored aluminum. And it may be fixed or operated electrically, and fitted with a sun blind and fly screen. Installation is similar to that of a hatch; there is no maximum deck or roof thickness.

Webasto Thermo & Comfort North America Inc., 15083 North Rd., Fenton, MI 48430 USA, tel. 800–215–7010, website


The Art of Concealment

Custom hiding placesSteve D’Antonio (Both)

Marcali specializes in custom hiding places, such as this wall hanging, and this table with secret door.

At the Miami Boat Show last winter, I was drawn to a display that contained, among other things, firearms. As a competition rifle and pistol shooter I couldn’t help but stop to learn more. These firearms weren’t on display per se; in fact, they were concealed in a unique fashion. The booth contained a variety of furniture that looked normal and unassuming: end tables, shelves, framed pictures, and bulletin boards, while other pieces had compartments opened to reveal valuables, cash, passports, jewelry, and firearms.

Concealing valuables is important to many boat owners. I rarely inspect a vessel over 50′ (15.2m) that isn’t equipped with one or more safes—the hard approach. So it’s no surprise that there’s a demand for products and fixtures that conceal important items. Among other things, Marcali Yacht of Fort Myers, Florida, offers a range of semi-custom and fully customized products designed, unlike a safe, to effectively hide virtually anything, from documents to an entire room in homes, offices, and aboard boats—the soft approach.

Looking at the closed items (in concealed mode), it was impossible to determine that they contained secret compartments, and equally impossible to open them without knowing how. Marcali concealment products don’t unlock with ordinary keys or combinations; instead, a magnetic trigger waved over the right location is the secret combination.

From the company president I learned that Marcali boasts 29 years of production without ever having an installation breached. Semi-stock components such as small tables range from $300 to $1,500; their specialty is fully custom installations, wherein they travel to the vessel to carry out their unique tradecraft. For more on their products and services, visit They are nec­essarily secretive, so don’t expect too much on the website.

Marcali Yacht Brokerage & Consulting, 1401 Lee St., Suite B, Fort Myers, FL 33901 USA, tel. 888–802–5381 or 239–275–3600.

—Steve D’Antonio

The end.