Courtesy Gunboat The Gunboat 68 (21m) is the first model launched by the new ownership of the company. Two boats are in the water, and two more are in build at the facility in France.
Actually, this builder of high-performance luxury cruising-catamaran sailing yachts has been back since 2016, the year Grand Large Yachts (parent of Allures, Garcia, and Outremer) bought the assets of Gunboat and relocated them from North Carolina to La Grande-Motte, France, where it commenced construction in a new 38,736-sq-ft (3,600m²) assembly facility. Gunboat founder Peter Johnstone, son of Bob Johnstone (J Boats, MJM powerboats), had declared Chapter 11 bankruptcy in May of that year. Production had originated in South Africa, moved to Xiamen, China, briefly to Hudson Yachts in an attempt to economize, and then to North Carolina (see “Building the Big Guns,” Professional BoatBuilder No. 144) before succumbing to financial woes after 14 years.
During the period between bankruptcy and purchase, the owner of an incomplete Gunboat 55 (16.8m) retained designer Nigel Irens to modify the boat, Vai Vai, to 57‘ (17.4m).
Johnstone created a boat that could cruise the world in safety, and with performance bettering that of the catamarans designed for the charter trade. Most are intentionally underrigged for safety, generally operating at 8–10 knots; Johnstone sought and routinely achieved faster double-digit speeds. The first South African boats were designed by the California firm Morrelli & Melvin Design and Engineering (see “M&M,” PBB No. 72).
Today, with managing partner Benoit Lebizay at the helm, Gunboat designs, engineers, and builds new models with cutting-edge technology. In January 2019, the company launched its first new boat, the 68‘ (20.7m) Condor, which has a removable interior for racing. Next was #6802, Dash, in July 2019. Two additional yachts, #6803 and #6804, are in build.
Gunboat now has French DNA
Design and engineering are by the French company VPLP (see “Flying Machines, Part Two,” PBB No. 91), one of the premier designers of high-performance multihulls for racing and cruising. Those include the Macif, the 100‘ (30m) Ultime class trimaran that set a solo singlehanded round-the-world speed record of 42 days, average speed 27.2 knots (see PBB No. 181, page 18). Styling, of course, was extremely important to attract the kind of buyers Gunboat wants, so Patrick le Quément, a multiple design-award winner and former designer at Ford and Renault, and Christophe Chedal Anglay were enlisted to develop the look. Marc Van Peteghem (the VP of VPLP), based in Paris, performed the weight studies and systems planning, while Vincent Lauriot-Prévost (the LP), in the Vannes office, executed the lines, structure, and sail plan.
While the first Gunboats were laminated with vacuum-bagged polyester and E-glass, advances in materials and processes compelled the company to turn to carbon fiber for reinforcements. Major parts—hulls and decks—are infused in-house. According to the Gunboat website: “If you take a cursory glance at the material choices, prepreg offers about a 15% weight saving on a composite structure. While it’s easy to get excited about that at face value, the devil is always in the details. On a typical Gunboat, the composite structure only makes up about 30% of the total displacement. A percentage of a percentage gets pretty small pretty quickly, to the point that building in full prepreg carbon did not justify the additional costs and complexity involved.”
European Supply Chain
William Jelbert, who manages construction, elaborates: “All tools are female molds, E-glass monolithic—same technology used to build 100+ boats out of. It was the technology available to us in Europe, and we wanted really fair molds to reduce fairing, and the big gelcoat-type boats around here need really fair tools because they are doing gray gelcoat boats. Our plugs were 5-axis foam machined, filler machined, then final faired by hand. We made the entire hull mold off of a one-piece plug for best fitting—always outsourced, as tooling is not our specialty. In Europe you have a great supply chain with a lot of specialization. We used a tooling company in western France.
“Everything structural is carbon. Anything that can fit on a truck is made by Fibre Mechanics and is prepreg. Why? Because they are best at prepreg, and this was an opportunity to save weight in a value-for-money way. Doing the hull and deck in prepreg would have meant very expensive infrastructure, tooling, and skills. We stuck with what we were good at: infusion in-house, prepreg outsourced to the best we could find.
“For a little partition panel that separates a compartment and is not structural, we use E-glass; it is more affordable and flexible, so tends to go along for the ride better. It is the same weight as a carbon panel would be.
“Corecell is used in everything that needs core in the structure—hull, deck, bulkheads. We use some PVC core for nonstructural partitions and Nomex honeycomb for the furniture, which is outsourced.
“All the structure is NDT’d [non-destructive tested] by a U.K. tester who works for small teams like Ineos Team UK and Hugo Boss.”
Courtesy Gunboat The interior structure, including these massive bulkheads, is made by Fibre Mechanics of prepreg carbon, much of it cored with Corecell and with North Thin Ply Technology robotically placed tape.
Stringers, bulkheads, and other flat panels are made by Fibre Mechanics utilizing North Thin Ply Technology (NTPT), described in this column in PBB No. 169. To summarize, the Swiss company first developed the product for making sails, specifically the black carbon sails for the America’s Cup yacht Alinghi, which won the 2007 event. It then made parts for F1 racecars, and found a partner in U.K.-based Fibre Mechanics, founded by former Green Marine employees, to move into yacht building. NTPT employs an Automated Tape Laying machine to “lay down” super-thin 12“-wide (300mm) tapes of prepreg carbon on a table to form computer-designed panels with the fibers oriented to the load paths. The panels are cured in Fibre Mechanics’ two autoclaves at 230°F (110°C). In fact, the entire interior structure is outsourced to Fibre Mechanics.
Fibre Mechanics’ founder and managing director, Geoff Stock, who has compiled an impressive résumé first with Jeremy Rogers and then Green Marine and SP Systems, says, “We make all the structural panels, 73 in all, plus some solid-carbon monolithic structures. Also very lightweight interior cladding panels, mainly Corecell but some Nomex. Everything is machine-cut prepreg, and, yes, we use significant amounts of NTPT material.”
To install these parts, Gunboat uses Spabond structural adhesive. Gelbert says, “Some glue joints are pure glue but mostly glued and taped. All major structural bulkheads are glued and taped using vacuum.”
The Gunboat 68 is offered with options, including asymmetric or symmetric daggerboards, long or short longeron/bowsprit, choice of boom length, and a fixed spar or rotating wing mast.
Gunboat, 1 Washington St., Newport, RI 02840 USA.
Fibre Mechanics, Waterloo Rd., Lymington, Hampshire SO41 9DB, U.K., tel. + 44 (0) 1590 427007.
NTPT, Chemin du Closel 3, 1020 Renens, Switzerland, tel. +44 21 811 08 88
