In 1947, when I was 8 years old, I learned to sail in the crystal-clear, balmy waters of the East African coast. On home leave in England, my father had found an old International 14 foot sailing dinghy – in a shed, with chickens in it. He cleaned her up and shipped her out to Tanga, where he used her to annoy the members of the local yacht club, who mostly sailed locally-built Yachting World 16 foot Sharpies. The full International 14 rig was hard work and the massive bronze board made the centreboard case leak, so he reduced the rig to something akin to that of a Merlin (they hadn't yet amalgamated with the Rocket in those days) and fitted a wooden centreboard. To rub salt into the wounds of the other members, he then taught me to helm her – and we still managed to be on the lawn drinking lemon barley water as we watched the second boat finish.
There was, however, one type of boat that we couldn't outsail on a reach – the local fishermen's ingalawas. These were lateen-rigged canoes about 20 feet long. The hull was a hollowed-out tree trunk, with simple plank outriggers lashed to it. A rope halyard passed through a hole in the top of the mast and was tied back to the weather outrigger. They couldn't be tacked – you gybed them, letting the sheet free and releasing the halyard a little so that the yard could lift over the top of the mast and settle on the other side, then you tied the halyard to the new weather outrigger before working along the foot of the sail to retrieve the sheet. In a breeze a keen crew member would stand on that weather outrigger, hanging on to the halyard for support. Under these conditions, there would usually be a third crew member bailing hard. They are still in use today, and even sail on the open sea to the offshore islands of East Africa. The only difference is that they use synthetic ropes, as you can see in the photo below..
Some current sailing craft designs are very sophisticated, but the basic hull types have been around for a very long time. Monohulls have only one hull and stay more or less upright under the righting forces exerted by fixed or moveable ballast (which could be just the crew). Catamarans have two identical hulls held together by some kind of bridging structure. Other multihulls have a main hull and one or two smaller floats known as amas – a trimaran is symmetrical side to side with two amas, and a proa is symmetrical end to end with one ama.
Using powerful computer programs to simulate the way they will behave has led to advances in the design of modern sailing craft hulls well beyond what was achieved previously by towing scale models in a testing tank. This is particularly true of ocean-going multihulls, the best of which are now less likely to turn upside down than monohulls – although the monohull will right itself afterwards.
It's easy to imagine early man taking to the water by sitting on a log, and slowly improving on that by hollowing it out to make a canoe, but in some parts of the world he floated around on bundles of reeds instead, which he later learned to shape into more efficient craft. Even today, reed boats are not confined to inshore waters. Take a look at these ones in Haunchaco, on Peru's Trujillo beach. They were riding the surf long before the modern sport was invented.
These hull forms, and the simple raft, evolved long before anyone tried adding a mast and sail, which is the point at which we start getting interested.
Let's ignore multihulls for now, and concentrate on how monohulls have changed over the millennia. Like the rest of mankind's technology, progress was very slow until well into the first millennium CE.
Boats that remained upright under paddles or oars were stable enough to carry sail off the wind, and these have been around for over 5,000 years – pictures from 3,200BCE show reed boats sailing on the Nile. In 1970, Thor Heyerdahl sailed a replica across the Atlantic from Morocco to Barbados, confounding those who believed it would get waterlogged and sink before he got there.
If you have trained teams and good discipline, you can steer even a large vessel just using its oars or paddles, but a sailing boat needs a dedicated device. In the first millennium CE both Asian junks and, a few centuries later, Viking ships started to carry sails. They started out, like the ancient Egyptian reed boats, using a steering oar on one side of a hull with a round or pointed stern. Only centuries later did both types grow larger and develop a flat transom stern with a rudder hung in the middle of it.
Junks were (and still are) built like large punts. Heavy slab sides are connected with massive bulkheads, then the flat bottom is planked in. They are strong and rigid, and often the bulkheads are made watertight. Contemporary observers claim that it was rocks and shallows that their captains feared, not storms.
By the time of the Song dynasty (960–1279 CE), some junks were huge – contemporary accounts talk of 500 foot ships with nine masts. Many modern scholars believe 250 feet is more likely, but archaeologists have found the remains of a rudder that would have been about the right size for a junk at least 400 feet long. They would have been by far the largest wooden ships ever built, and it's not clear why they didn't fall apart. European sailing ships didn't reach that tonnage until after Nelson's time, by which time iron frames were being used in highly-stressed areas. The massive and rigid box construction must have helped. The unstayed masts and the easily-reefed junk rig must have been kinder on the hull under storm conditions than even a struck down 18th century square rig, but if you've sailed in the South China Sea you know, the South China Sea is no millpond.
Sailing junks have been around the orient for nearly two thousand years, but a very different design dominated the seas around Europe for 300 years, starting towards the end of the 8th century. Coming mostly from mountainous fiord settlements where it was easier to travel by boat than by land, the Vikings developed long, shallow draft boats. They were built much the same way that my grandfather built dinghies – starting with the keel, stem and sternpost then working up to the gunwales with overlapping planks riveted together. My grandfather would fasten his planks with copper rivets about the width of his hand apart, but the Vikings fixed their oak planks with iron rivets about a foot and a half apart. The seams were caulked, but bailing must have been an essential activity even in calm weather. Like the skiff grandpa built for me, Viking ships would flex under load. A massive keelson sat on the keel but was not clamped rigidly to it. This spread the load of the mast heel without pushing the keel downwards and opening the garboards, but the hull would not have been rigid enough to carry a powerful rig. They were fast rowing boats with a small sail. The cargo boats had more freeboard and the centre was kept clear as a hold, but the warships and passenger craft were open boats with minimal freeboard. The North Sea in a gale must have been an exciting ride, but that's what the Vikings were brought up to expect.
For windward sailing, the Viking ship with its fine lines and its keel is potentially better than a junk, but some junks were fitted with leeboards. Combined with the more efficient, easily-reefed sail plan and the unstayed masts, this probably meant that they could still claw off a lee shore under conditions that would have wrecked a European square-rigger.
There is a rig that dominated the Mediterranean in the Middle Ages – the triangular lateen sail set on a short, forward-raked mast. The earliest evidence of it is in a 1st century BCE wall painting in Alexandria, but it is still seen today on the Nile and down the East coast of Africa, as well as on the seagoing Arab dhow. In its heyday, San Francisco's Fisherman's Wharf was crowded with 'dago boats' - lateen-rigged feluccas. Able to sail at about 100 degrees to the wind rather than the square-rigger's typical 130 degrees, the rig becomes too big to handle on larger craft, and is less effective in a following wind, even on a boat with two or more masts.
Early sailing craft were developed as warships or cargo carriers, but by 1500 other uses drove the development of fast, seaworthy small craft in Europe. While fishing boats operated daily out of estuaries and protected harbours, bluff-bowed, shallow-draft busses and the like were adequate. Those who were obliged to keep their boats on open beaches and launch through surf developed hulls that were easily-driven and the very simple loose-footed lug sail – close-winded and easy to raise or lower. These hulls had a shallow forefoot and straight keel whose deepest point ended in the rudder – you could run it straight up a shingle beach and leave it there.
Once salt production ceased to be a state monopoly, fishing boats could venture far away from home for extended periods. The Brixham Trawler was the high point of this development. Initially Gaff cutter rigged, but by 1890 the larger ones were ketches. They could take anything the English Channel and the Atlantic could throw at them, and there are owners today that claim that their renovated or replica boats are among the safest, most comfortable and most easily-managed craft for open water cruising.
Another boat that needed to be fast, and seaworthy enough to operate far from land in all weathers was the pilot boat. The Bristol Channel Pilot Cutters were the supreme example of this class of sailing craft, even after the ships they were serving changed from sail to steam powered. They did not need to carry cargo, but needed to be manoeuvrable - so they were lighter for their length and sail area than a trawler, with a shorter keel.
The maximum speed of a hull that does not plane is governed by the length of the wave it generates, and hence proportional to the square root of its waterline length. The Bristol Channel Pilot Cutters did not have near-vertical stem and stern. The overhanging bow increased the waterline length slightly when the boat was heeled, and the counter stern even did so when it was upright, squatting in the trough of its own wave. This hull form was also used for larger craft such as the Grand Banks fishing schooners and the yachts of kings and princes.
As steam power took over from sail for commercial purposes, development of sailing craft passed to the world of sailing for pleasure. Private yachts were quite common in Holland back in 1600, but they were based on existing working boats and small warships – many even carried cannons.
During the early part of the 19th century interest in yacht racing had expanded. There were still wealthy owners who wanted to race their large craft to see who could get home first, but many more had smaller, slower boats and wanted a handicapping system to allow them to compete with a reasonable chance of winning. Various European countries and the USA all developed 'rating' rules based on the way cargo ship volume was estimated for tax purposes. Although this measurement was known as 'tonnage', it was an estimate of the number of tuns (large barrels) a ship could carry, not her displacement in tons.
Given a rule that estimated volume, but knowing that maximum speed was governed by waterline length, yacht designers made the obvious move. Racing yachts became long and narrow, with long overhangs to increase their effective waterline length when heeled.
During the first half of the 20th century, hull building technology didn't change much, but sail material and rigs did. Racing yachts developed weaker hulls, with much of their weight contained in the ballast at the bottom of the keel. After only a few years, a successful racing yacht would not only be outclassed by designs that found new ways to take advantage of the measurement rules – it would also be falling apart. By the 1950s, the number of cruising and racing 'boats with lids' had grown dramatically, and the middle classes had established themselves in a world previously restricted to the rich. Rating rules were modified regularly in an effort to encourage the design and construction of craft that would be suitable for cruising long after the pinnacle of their racing careers. Up to a point, they succeeded – hulls became much beamier, providing more accommodation in shorter hulls.
During the second half of the 20th century, technology advanced at an ever-greater rate, and both the rating rules and Lloyd's Rule scantlings for yachts were fairly quick to assess and adapt. New yachts became lighter and stronger. Rigs became more powerful as synthetic fibres replaced cotton for sail materials, and aluminium alloy spars replaced wooden ones. Stainless steel wire rope, and then solid forged stainless steel rod, became standard for standing rigging. Aluminium, steel and GRP, followed by more complex composite systems, replaced wood as the material of choice for most hulls. Successful wooden racing craft were still built in the 1960s, but the increasing size of the market made series production using moulds to lay up resin-bonded fibres of various types, with the accompanying lower price to the potential buyer, a good business proposition. These synthetic materials were also much easier to maintain than painted or varnished wood.
Meanwhile, the world of dinghy racing made real progress. As marine plywood and waterproof resin adhesives allowed builders to abandon the old nailed and riveted planks, the hulls became a light, rigid monocoque like the fuselage of the WWII Mosquito aircraft. People learned that their boats sailed faster upright, so a heavy centreboard became pointless. With weight much reduced, heeling forces counterbalanced by a hiking crew and a hull designed to generate hydrodynamic lift (called planing), a 14 ft dinghy could outpace a 30 foot yacht with ease. As relevant technology advanced, small craft adopted it, sometimes updating the rules for restricted classes, and sometimes by creating new classes. Crew weight was moved further outboard with the aid of trapezes – at first for the crew, but later to include the helmsman.
Dinghy racing flourished among those who had neither the money nor the time to campaign large yachts, but increasing competition in the races made even dinghies too expensive for the young with time on their hands and a desire for adventure. The sailboard appeared on the scene. It was cheap. You could carry it yourself, and its power-to-weight ratio was higher than that of any skiff or dinghy. In addition, the board could remain flat, or edged like a ski, while the mast and sail were canted to windward, helping to lift the board and make it easier to drive over the water.
By the end of the 20th century, the kiteboard had arrived on the scene. Now the boards derived motive power from stronger winds more than 100 feet above the sea surface.
With the arrival of carbon fibre reinforced laminate technology that was well within the skills and budgets of small dinghy sailors, the 11 foot Moth class dinghy adopted hydrofoils attached to centreboard and rudder. In moderate breezes they now tear around like pond skaters, outsailing larger skiffs in certain wind and water conditions.
Meanwhile, 'full size' yacht design stagnated. Technology advances improved their performance slightly, but the combination of fixed ballast keel aided by form stability derived from the hull cros-section shape could not provide the power-to-weight ratio need to make a hull plane – although some hulls did surf slightly downwind in big waves. Rules based on preconceptions about yacht design were holding back innovation. No-one wanted to encourage major risk-taking and the obsolescence of the legacy fleet.
By 1969, the International rating rule grudgingly allowed lifting keels. This allowed skippers to reduce hull resistance when far enough off the wind for the keel ballast to be unnecessary, but did nothing to increase sail carrying power. I still remember sailing on a dead run in a moderate breeze during 1970 Cowes Week, about a quarter of a mile behind Dick Carter's Red Rooster. We could hear the screams of the girl clinging to the backstay as Rooster dipped first her boom end then the spinnaker pole as she rolled. Whoever was helming skilfully avoided what would have been a wild broach, but soon lowered the keel again to damp the roll.
Long before the rating rules accepted them for racing yachts, L Francis Herreshoff proposed a canting keel in his book Common Sense of Yacht Design, and a 1975 patent describes a system in which a canting mast is linked to the keel, canting it to windward while the hull remains upright. However, since the keel also provided the side force necessary for windward sailing, others improved on the idea by adding either a centreboard or, better, two canted leeboards used one at a time.
Jim Young built Fiery Cross, a 45 foot double ender with a canting keel but no centreboard, in Auckland in 1959. The first boat to carry a canting keel and separate daggerboard was the 55 footer Red Herring. The last wooden boat built by Goetz Custom Boats of Rhode Island, her keel can be canted and lifted, but not both at the same time. Dave Hubbard designed her to a concept by van Alan Clark that expanded on LF Herreshoff's idea. Steve Clark still owns and races her.
The first offshore racing boat to use a canting keel was Pete Goss's Open 50 Aqua Quorum, which he raced in the 1996-7 Vendée Globe. She proved the design, and Pete's seamanship, when he rescued Raphael Dinelli in a southern ocean storm during that race.
Now canting keels are common in ocean races. Currently, there are two main types. The Volvo Ocean Race and Vendée Globe boats are triangular sleds with twin rudders and twin daggerboards. Sailed with the hull heeled, they are halfway to being catamarans. The other form, popular among racing maxi yachts such as regular Sydney-Hobart winner Wild Oats XI, uses a system patented by CBT. Two vertical foils along the centreline provide both lateral resistance and steering. Since these boats are sailed more or less upright, the idea is filtering into the cruising world in a way that the Volvo and Vendée boat concept has not. Let's hope that CBT don't stifle monohull innovation once again by hanging on to their patent beyond its sell-by date and wasting everyone's time and money on lawsuits.
So what of the future? Well, there's the SpeedDream project, brainchild of Vlad Murnikov. Ignoring all the current rating rules, he and his team are working on a monohull concept with a keel that cants right out of the water!
by Michael Kingdom-Hocking for YachtPals.com