How (and why) wood is making a comeback in yacht building
- Rupert Holmes
- May 30, 2023
Rupert Holmes reports on latest developments in wooden yacht construction, and why this ancient material is being used for hi-tech contemporary design
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Why would a naval architect and structural engineer used to working with cutting edge materials for America’s Cup teams, including INEOS Britannia, and companies like Airbus, be excited about working with wood?
“It’s quite simple for me,” says French designer Thomas Tison, “Modernity does not neglect where we all come from – on the contrary it makes the best of it. In a way a boat is a heritage, so to ignore wood would be to ignore the essence of yacht design and building.
“Carbon fibre is only an evolution from this heritage and reinstating wood as a modern material increases the number of options a naval architect has for creation and performance.”
Tison designed the stunning, contemporary 48ft offshore racer Elida which launched last year, and currently has a timber/epoxy 40ft high-end daysailer on the drawing board. To optimise Elida’s weight and stiffness Tison tested three different timber and glue laminates at an Airbus facility. “What we found was very interesting,” he told me. “The existing data was 20 years old, but now we can carefully select the glue and timber, so the figures for our laminates were stiffer than predicted, with the sitka spruce an order of magnitude better than expected.”
Elida is built of diagonally planked sitka spruce covered with a 3mm mahogany veneer. Additional internal stiffening is provided by local layers of 200g carbon fibre. The result is a very stiff structure – projected forestay loads match those used on TP52s, yet the total weight of the 48ft hull shell is only 1,000kg.
Tison’s next project is a very high end 40ft daysailer. Construction will be an evolution of Elida’s, giving a strong and stiff structure that meets Category A requirements, yet total displacement is only 3,700kg. He also has a concept under way for a 45m superyacht built in a similar manner.
Outlier is a cold-molded custom 55-footer designed by Botin. Photo: Billy Black
Traditional skillset
The enthusiasm naval architects young and old have for wood/epoxy composite construction is striking. Many of today’s stand-out new designs on both sides of the Atlantic are built this way and it’s often the best option for one off builds and short production runs. Key advantages include stunning aesthetics, stiff, lightweight structures and excellent longevity.
Today British yard Spirit Yachts is perhaps the most well-known specialist in this form of construction and their wood-as-art concept is well documented, including the sculptural approach taken with the Spirit 111 Geist.
However, examples of other yachts abound, including Rob Humphreys’ Tempus 90 superyacht. This was built in Turkey, which unlike many countries never lost its wooden-boat building industry. As a result plenty of yards today are familiar with working with epoxy/timber composites. And many other top-notch recent wooden yachts have been built there, ranging right up to superyacht size, including Andre Hoek’s PC Yacht range and a number of his Truly Classic designs.
Sailing Art Full Tour Of The Extraordinary Spirit 111 Superyacht
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Britain has its own strong tradition of wooden-built designs: the Elephant Boatyard on the River Hamble has a long history of building, and maintaining, timber/epoxy yachts, including the Barracuda 45 built for Bob Fisher in the late 1980s.
Wood was the medium successful IRC raceboat designer John Corby made his name with in the 1990s and 2000s. And it was the choice of one of the UK’s most successful yacht designers, Stephen Jones, for his own 46ft one-off Meteor, launched in 2006. She was built in Grimsby by Farrow and Chambers, which also built two cedar epoxy yachts for former Yachting World editor Andrew Bray.
On the other side of the Atlantic, several New England yards are active in building new custom and semi-custom yachts in wood/epoxy. Notable recent examples include the Lyman-Morse 46, Brooklin Boat Yard’s Jim Taylor-designed 44ft Equipoise, and the Botin custom 55-footer Outlier. A long list of other notable recent launches include Anna, a 65ft Stephens Waring design built by Lyman-Morse and launched in 2020.
The beauty of wood inside a hand-crafted Spirit. Photo: Paul Wyeth
Build techniques
UK-based designer Rob Humphreys has a long association with this build method, having designed his first vessel in wood in the late 1970s, followed by a string of others, from 22-footers to superyachts, over the following decades. Humphreys remains keen to design more: “The only thing that’s holding us back really is an issue of market education,” he told me.
The medium is often poorly understood, with few people realising the benefits and many assuming it has the same drawbacks as traditional timber construction, or that the technology hasn’t moved on since cold-moulded wooden boats of the 1960s. These were built with resorcinol glues that were originally developed in the early 1940s, but required considerable clamping pressure to create a reliable bond and couldn’t be used as a coating to protect timber.
The epoxy revolution, driven enthusiastically by brothers Meade, Joel, and Jan Gougeon in Michigan in the early 1970s, marked a turning point for boatbuilding. “They got chemists to reconfigure epoxy to be runny enough to saturate the wood rather like a varnish,” explains Stephen Jones.
Even though epoxy doesn’t penetrate deep below the surface of timber, it sticks so well that, unlike paint and varnish, it forms a genuine barrier that keeps water out of the timber in the long term. As a result these boats have potential to last as long as any fibreglass structure.
Lyman-Morse 46 hull completed and being turned outside the boat shed. Photo: Alison Langley/Lyman-Morse
There was another key advantage. “It could also be thickened as required for glueing and, most importantly, gap filling,” adds Jones. This significantly speeds up the build process. These vessels are generally inherently stiffer and lighter than conventionally built fibreglass yachts and it was a preferred build method for performance yachts before cored composites became reliable.
Meade Gougeon’s 35ft trimaran Adagio, launched in 1970, was the first large all epoxy bonded and sealed wooden boat built without the use of mechanical fasteners (and is still sailing on the Great Lakes over 40 years on). Three years later the brothers built the Ron Holland-designed 41ft IOR Two Tonner Golden Dazy, ahead of a slew of further designs including a 60ft trimaran for Phil Weld’s 1980 OSTAR single-handed transatlantic race, before race organisers imposed an upper size limit. Weld subsequently had the 50ft timber/epoxy tri Moxie built by Walter Greene, in which he won the OSTAR.
Over the years precise construction methods have varied, although all but a handful of boats are built with several layers of timber with the grain running in different directions to create a stiff structure. Some have a purely cold moulded construction, with larger boats often employing four or more layers laid at around 90° to each other. This creates a lightweight and stiff structure that can be protected from impact damage with epoxy and glass cloth. The Lyman-Morse 46, for instance, is built of four layers of vacuum glued Douglas fir and western red cedar.
Hand-built expertise at the Spirit yard in Suffolk. Photo: Spirit Yachts
Others start with a layer of narrow planks, termed strip planking. This had been a construction method long before the use of epoxy, but it became much more popular thanks to the development of the Speed Strip technique by Sunderland timber merchant Joseph Thompson & Co (now renamed NYTimber) with help from Farrow and Chambers. The planks have a loose tongue and groove profile, allowing them to neatly conform to the hull shape and giving space for thickened epoxy glue.
Speed Strip also eliminated the need for scarfs to be cut where planks are joined and reduced the number of mechanical fasteners needed. This reduced planking time by a quarter, and clean up and fairing time by 70%. An additional advantage, Jones says, is the “predominance of fore and aft timber strips/planks increases global hull stiffness – the ability of the hull to resist rig loads.”
Around the same time Humphreys was also working on ways to reduce build times. The hull of his H22 sportsboat, which was available as a flat-pack kit with CNC cut components, could be assembled from scratch in a few hours by one person. I know of 40ft offshore racing yachts that were planked up in a week.
Strip planked boats can be built over laminated frames that become part of the final structure, and don’t require a mould that is subsequently discarded. These frames are surprisingly quick and easy to create – at Spirit Yachts, for instance, they’re assembled on full-size print outs of the boat’s plans laid over a plywood floor. This allows each piece of timber to be bent by hand into exactly the right shape and held in place using spikes driven into the floor. They’re then clamped together in situ while the epoxy cures.
The Lyman-Morse 46 interior shows off its timber construction, with plenty of white painted surfaces for an airy feel. Photo: Alison Langley/Lyman-Morse
Originally cedar was used for Speed Strip planks as it’s lightweight yet very resistant to rot, although other species with similar properties, including Douglas fir and sitka spruce, are also suitable. Typically two thinner outer layers of double-diagonal planking are added outside the strip planking.
In the case of Zest, our 36ft Rob Humphreys design built by Farrow and Chambers in 1992, this forms a 20mm-thick tri-axial construction with the grain of the timber oriented in three different directions. Larger yachts may have four or more layers outside the strip planking and a few boats have an additional transverse skin to help strengthen the area around the keel.
Impact protection
In all cases the whole lot is glued together and sealed from water ingress with epoxy. Therefore no more maintenance is needed than for a fibreglass hull and it will never succumb to osmosis.
Jim Taylor, designer of the 44ft Equipoise and 50ft Rascal, both recently built by Brooklin Boat Yard in Maine, says that in North America this construction is likely to be referred to as cold moulded, with the term referring to the outer layers, rather than the inner skin of strip planks.
Modern wooden builds created using latest CAD at Spirit Yachts. Photo: Spirit Yachts
Equipoise was built with a first layer of fore-and-aft tongue and groove larch planking which is epoxy bonded to the laminated keel, keel floors, bulkheads and ring frames. Outside of that two layers of diagonal 3/16in (5mm) paulonia were vacuum bagged at +/-45° to the initial planking. Then a further layer of tongue and groove larch was laminated over the paulonia, again in a fore and aft orientation. Outside that is a protective layer of epoxy/glass. Displacement is little more than six tonnes, despite an unusually large 44% ballast ratio, allowing a large rig without the drawbacks of excessive draught.
“There is a whole lot to like about this type of construction,” Taylor says. “The approach is cost effective and the result is extremely attractive on many levels. The boats are light, strong, tough, quiet and well insulated thermally. A bright finished inside skin can be integrated into an especially elegant interior, the construction materials are environmentally sustainable, and there’s not a lot of waste. They’re not as light as carbon skins over lightweight core, but they are much more liveable and not nearly as fragile or as expensive.”
The outer glass/epoxy sheathing can vary from light cloth for impact protection, through to heavier laminates that add structural strength in high load areas such as around the keel. A few boats have glass only outside, rather than additional layers of timber, but these heavier laminates need more work and filler to create a fair surface.
Carbon stiffening for Elida. Photo: Emeric Jezequel
Of course, if the outer sheathing is punctured, then it will need to be repaired quickly, but a quick application of epoxy filler is all that’s needed until a neat long-term repair can be made.
Developments and refinements over time include vacuum bagging the various layers of timber together, along with the external protective layers of glass cloth. At the high end carbon reinforcement is increasingly used strategically to add further stiffness where necessary, without a significant weight penalty.
Elida’s varnished topsides look stunning, while those of the 1987 Humphreys-designed Apriori and 1988-built Old Mother Gun of 1988 still look great. There’s therefore a huge temptation for anyone building a wooden yacht to opt for similar finishes. However, it’s important to note in these cases the epoxy needs a more traditional varnish for UV protection and that can require a lot of maintenance. On the other hand, today’s polyurethane paints can last up to a decade in dark colours and Meteor’s original white paint from 2006 still looks almost new.
L’Été is a new 40ft daysailer design by Thomas Tison.
Modern look
On the other hand, varnished bright work on deck and coachroof sides are subject to less wear and tear than topsides. Jones says these are easy to prep for varnishing if designed with simple surfaces without fiddly detail. The cleaner style of modern classic deck structures also reduces water retention, so surfaces dry quickly. “It can still look the part but becomes less onerous to keep,” says Jones.
Below decks it’s easy to fall into a trap of showing off so much natural timber that the interior becomes dark; a strategic mix of white painted panels and clear timber finishes gives a much brighter result. The Spirit 72, for instance, has satin painted panels and a carefully planned LED lighting system to enhance the warmth of the natural timber.
The Spirit 111 has a sculptural cockpit and interior. Photo: Spirit Yachts
Hull windows are possible and, even if maintaining a classic external appearance is a priority, it’s possible to allow a lot of light in from the deck. Spirit Yachts’ trademark fantail window is an excellent example of this.
Alternatively, interiors can be absolutely contemporary in style, as seen in RM Yachts’ 29-43ft range of plywood/epoxy performance cruisers. Plywood also offers excellent stiffness in relation to weight and is an ideal medium for today’s chined hull shapes. At RM all the pieces for an entire boat are delivered on pallets, ready for immediate assembly. Hulls are built over frames of substantial chipboard set up on jigs. Assembling a hull is therefore a straightforward process that doesn’t require a full mould.
The Ace 30 scow bow short-handed IRC raceboat also employs plywood/epoxy construction. It’s an approach the builder says considerably reduces the carbon footprint of building each boat.
Matt Newland of Swallow Yachts tells me their Whisper 300 retro-style planing motor cruiser has demonstrated that at sizes above 30ft an epoxy/timber construction can compete directly on labour hours with conventional fibreglass boatbuilding. The company’s next model, the Bay Cruiser 32, will be a traditionally styled, but very lightweight and quick, 32ft trailerable weekender made of clinker-style plywood and epoxy.
Other forthcoming projects include a range of 45-70ft modern classics by Stephen Jones and illustrator/designer Jonty Sherwill that will be built by the Elephant Boatyard.
These boats will also be more sustainable than their contemporaries built using conventional glass fibre or more advanced composites. The quantity of epoxy used for the build is small and bio-sourced resins can be used without the requirement for a full size mould. The result is that the carbon footprint associated with building the Ace 30, for instance is 1.9 tonnes, but would be more than three times that value for a boat of conventional construction, even before accounting for building the moulds.
