Why multihulls are fast
A conventional sailing yacht gets its stability from a heavy keel. A multihull gets it from width. Two or three slender hulls spread far apart resist the heeling force of the wind without much ballast, so a multihull can carry a large sail area on a light structure. Slender hulls also make little wave, so for a given power they tend to be faster.
The trade-off is that multihulls are less forgiving when pushed too far. A capsized multihull is hard to right, and the same width that supplies stability can also make them awkward to berth. That balance of speed and risk has guided most of the development described here.
Light materials and big structures
Early modern multihulls were built from marine plywood, and later from glass-reinforced plastic. From the 1970s and after, designers increasingly used sandwich construction, where a light core such as foam or honeycomb is covered by thin skins. This gives stiff panels for little weight. Carbon fibre, valued for stiffness and strength relative to its weight, spread through yacht building in the following decades, first in masts and then in hulls, beams and sails.
These materials mattered particularly for multihulls because the loads on the crossbeams, or the structure joining the hulls, are high, and weight is critical to performance. A wide, light structure that can survive ocean waves was not achievable with traditional timber construction at large scale.
Trimarans and ocean racing
Much of the pioneering offshore work in the 1960s and 1970s was done by sailors who preferred trimarans, three-hulled boats with a central main hull and two floats. They were considered safer on long races because of the greater stability, and several early ocean races were won by multihulls, which led some organisers to question whether they should compete alongside monohulls. As a result many events created separate classes, and multihull racing developed on its own track, particularly in France.
Races such as the transatlantic Route du Rhum, first held in 1978, became important showcases. Over the following decades the boats grew steadily, and today the largest class, known as Ultim, includes trimarans of roughly 30 metres, sailed by one person or a small team.
Round-the-world records
A key benchmark has been the Jules Verne Trophy, created in the early 1990s for the fastest nonstop circumnavigation by any crewed vessel with no limit on size. The first holder, a catamaran skippered by Bruno Peyron, completed it in under 80 days in 1993. Later record holders were all multihulls, and the crewed time came down in steps, to around 41 days for a trimaran in 2017. Solo circumnavigations are ratified separately, and a solo trimaran passage at the end of 2023 was reported at a little over 32 days. Weather routing, satellite forecasts and tough, light construction all contributed. Exact figures differ between sources and are revised as new attempts are ratified, so they should be treated as approximate.
Single-handed circumnavigations by multihull have also been completed, which would have seemed implausible half a century earlier. Such passages are still dangerous, and outcomes depend heavily on weather and luck.
Foils
The most recent technical step is the hydrofoil. A foil is a wing shape underwater. When a boat is going fast enough, the foil produces lift and can raise the hull or hulls clear of the water, reducing drag dramatically. Hydrofoil craft had been experimented with for much of the twentieth century, including some sailing boats, but practical foiling for racing took time because of the demands on control and strength.
A turning point came in 2013, when the America’s Cup was raced in large catamarans designed to fly on foils at speeds well above the wind speed. These boats, with rigid wing sails in place of soft sails, drew wide attention. In the following years foiling filtered down to smaller racing catamarans, including Olympic classes, and to some very large ocean-going multihulls fitted with foils. Foils on offshore boats are used partly to lift the hull and partly to improve stability, and the effect is to raise average speeds.
Speed records on the water
Records for outright sailing speed are held by specialised craft rather than ordinary catamarans. Some of the fastest sailing craft ever recorded were experimental foilers, including a trimaran and a very narrow proa-like design, and various speed trials have been run in shallow, sheltered channels. Individual record figures vary with the distance measured and the organisation that ratifies them, so any single number should be checked against current records.
Costs and limits
Innovation has a cost. Carbon fibre structures, foil systems and complex electronics are expensive, and the risks of breakage and capsize rise with speed. Many sailors, even among those who enjoy cruising catamarans, never encounter this part of the sport. Whether foiling and extreme racing multihulls will remain mainly a specialist field or spread more widely is still an open question.
What can be said is that over roughly seventy years multihulls moved from an unorthodox alternative to a main arena of high-performance sailing. Their story is largely one of materials and engineering, building on older twin-hull ideas.