When glue changes wood
Longstanding know-how
For a long time, a boat was like a jigsaw puzzle, with the various pieces held together using nails, screws and bolts or mortise and tenon joints. In essence, the method of assembly remained unchanged and unchangeable: carpenters laid out on the ground a piece of keel carved out of a tree trunk, then positioned transversal arches known as ribs at right angles. They then nailed longitudinal supports, known as ribbands, to these ribs and covered all of this with carefully arranged boards. They sealed the gaps with oakum and a tarry paste to make the hull watertight. For the deck, they attached boards on transversal struts known as deck beams.
This know-how, handed down and refined from generation to generation, had a certain elegance and noble character. The choice of timber species and samples called for almost encyclopedic knowledge of the science of trees and the forests. The cutting down of large oak trees to supply the parts for the keel, stem or sternpost was almost ceremonial. Then, the shaping of the parts in a workshop with all the smells of wood and oakum, the bending of the boards in steam chambers, the adjustments made down to the slightest millimeter, all these ancestral practices were added to the expertise of the master carpenters. Far more than a trade, traditional boat building was an art.
And yet, for centuries, the hulls made in this way were not free from defects or flaws. Voluminous and heavy, not necessarily robust, not perfectly watertight, they were always vulnerable to the diseases affecting wood. That is why iron then steel started to take over in terms of building ships for war and trade. But recreational boating remained faithful to wood.
Wood turns a new leaf
Chemistry and mechanics changed all of this. Revolutionizing both boat building and naval architecture in the 1950s. Form had always followed function. Now, the material made it possible to invent different hulls. And yet, these continued to be made out of timber. But they no longer involved sections of tree trunks that had been cut up. Solid wood will be forgotten forever, along with, gradually, the various metal braces and pins. The arrival of new glues changed everything.
In the early 20th century, the chemical industry developed the first truly strong glues. A few decades earlier, in Sweden, the United States or England, the Nobel-nominee inventors (Alfred’s father) Mayo or Witkowski had submitted patents for the design of boards created by assembling thin sheets of wood, laid on top of one another and glued together at right angles. This gave sheets of variable dimensions which were at least as rigid as solid timber boards, but significantly lighter.
However, the first use of wood in thin layers actually dates back to ancient times. But it never gained momentum as there were no effective technologies for sawing tree trunks and no effective glues.
At the start of the last century, in the Baltic States and Russia, timber harvesting was progressing very quickly, with the development of band saws for spruce or birch logs, tree species that were particularly well-suited to being cut up like this. Alongside this, new sufficiently powerful hydraulic presses made it possible to compress the strips of wood that were glued together and transform them into a consistent material: plywood was born.
As often seen, wars combine both tragedies and accelerations with technical progress. The emerging aviation sector very quickly adopted plywood. Its mechanical properties were excellent and it was remarkably light. However, the navy steered clear of this new material: the new hulls were not very resistant to seawater.
But not for long. On the eve of the Second World War, the first synthetic glues, or resins, with unmatched mechanical qualities, made it possible to produce large gliders for the Allied airborne troops, as well as fighter-bombers, such as the famous British twin-engine Havilland Mosquito. The new resins were able to resist the cold, the heat and, above all, seawater.
The flying dutchman
In South Africa, a door manufacturer capitalized on this to extend his production to include “weatherproof” plywood terraces and wall cladding. His name was Cornelius Bruynzeel. Originally from the Netherlands, Bruynzeel was a regatta enthusiast and friends with the renowned Dutch naval architect Ricus Van de Stadt.
As a good exterior cladding specialist, Cornelius had understood how he could use a new plywood made of teak or okoume, which was both dense, light and rot-resistant, with a synthetic glue that was not sensitive to seawater: marine plywood.
In the late 1940s, the daring entrepreneur commissioned a sailing cruiser yacht in marine plywood from Van de Stadt, with which he took part in the famous Fastnet Race in 1951, the most prestigious ocean race at the time. He won in his class. His plywood Zeevalk was 12.56m long and weighed less than five tons, half as much as its rivals at the time.
Some might have been shocked by its lines: this was the first time that we saw an ocean hull with rugged features. But the material required this sharp angle, running from the rear to the front above the waterline, known as the chine. And it gave a hull bottom that was far flatter than was usual at the time. Sailing off the wind (wind abaft the beam), this hull was able to “plane”, rising partially out of the water like an outboard and reaching unprecedented speeds.
In France, the liberation of plywood
As sailing, and racing in particular, is a very small world, the Zeevalk’s performances did not go unnoticed in France. But the pioneers of the French recreational boating revolution had not waited for this to be convinced of the benefits of using marine plywood. When, in 1951, Philippe Viannay, the founder of the Centre Nautique des Glénans, asked Jean-Jacques Herbulot to design a beginners’ dinghy for his recently established sailing school, Herbulot got working right away. A DPLG architect, Herbulot was of course up-to-date with the latest technological developments. A keen regatta racer, who won a number of French championships and finished fifth at the Los Angeles Olympics (1932) in the leading “Star” class, he was also well positioned to know that weight was the enemy of both speed and the wallet.
He designed a 4.08m dinghy. His Vaurien was slightly bigger than the Argonaute, a small keel boat that Herbulot had designed during the war. But it was nearly 30kg lighter and considerably cheaper. Unlike its predecessor, the Vaurien was designed to be built with marine plywood. And to make the most of the standard plywood sheets, its angular hull lines were very simple. We once again saw the Zeevalk’s hard chine and flat bottoms.
Shortly afterwards, Herbulot designed the Caravelle, both a working vessel and a training boat, then the Corsaire, a tiny 5.50m live-aboard, but also a real ocean sailing yacht. The Corsaire, like all the new plywood units, was very simple to build: two longitudinal battens, supported by a few transversal elements, received the boards made up of two sheets with the only curve. However, its architect reserved the amateur building option for its cousin, the Cap Corse, which we will come back to later. These units very quickly moved on from the shores of the Îles de Glénan and spread across France, with its population looking to get away and enjoy time on the water.
In 1950, France finally emerged from the war economy. The ration cards were withdrawn. The previous decade’s deprivation and hardships led to increased interest in discovering different things. The Citroën 2CV, an “umbrella on four wheels”, made the shores accessible by car. With the new Herbulot units, like 2CVs of the sea, time on the water became affordable as well.
Demand surged, with the boatyards growing in number and size. Eight of them produced the Corsaire, which could even be bought at BHV department stores! Herbulot teamed up with a formidable businessman called Jacques Derkenne to distribute his models. In 1957, Derkenne’s companies – which also included a rigging distributor and a dedicated structure for amateur builders that distributed plans for the Cap Corse – handled more than one third of sales for sailboats built in France. And they soon grew from hundreds to thousands.
Stylish molded wood
However, plywood did not establish itself everywhere. More expensive, longer and more delicate, another wood building technique transformed the production of racing, regatta and luxury boats. In 1953, embracing modernity, the Caneton owners’ association – a dinghy over 5m and 200kg – adopted the outstanding plan from the British naval architect John Westell, known as the 505 (read as five o five, for 5.05 meters).
This dinghy’s magnificent hull was built with molded wood.
Like plywood, this process uses thin sheets of wood and synthetic glues. But the sheets are not assembled or compressed as flat boards before use, which makes it possible to give them the curved lines desired. They are placed one at a time on a male mold, made of small slats, with unlimited curves.
We start off by provisionally laying out the first thin layer of wood, at 45° from the keel. The following sheets cover this at 90° with successive layers glued on. This gives a hull that is not only light (130kg for a 505), but also consistent and free from any sharp angles.
The only downside: this technique requires professional know-how and far more labor hours than building with plywood.
Sails: The end of cotton
The growing number of sailboats and the spectacular increases in their performance levels brought about another revolution. Sailmakers in turn benefited from the new “water rush”. They were getting ready to introduce a new era. In the ports along the Atlantic and Mediterranean coasts, up until the 1950s, cotton reigned supreme on masts. This noble material had two flaws: it lost its shape very quickly under pressure from the wind and it did not like water, which is problematic when its purpose is to power boats. So, this was the swansong for cotton.
In 1954, a Star fitted with synthetic fabric sails won the series world championship. Known as Dacron in the United States, Tergal in France or Terylene in the UK, this modern material was a weave of polyester fibers. For sail production, to counteract its elasticity, its weft (threads perpendicular to the roll, as opposed to the warp) is reinforced alongside the sail’s trailing edge. In just a few years, thanks to its low weight, its resistance to both UV and seawater, and its reduced elasticity, Dacron went on to depose cotton. Paving the way for spectacular progress with the design, cutting and production of sails.
And this was just the start of a remarkable leap forward. While aluminum took the place of wood for mast building, polyester and its derivatives replaced hemp for rigging. The 1950s opened up growth in recreational boat use in France that was as striking as it was unexpected.
