Do you know your Bermudan rig from your DynaRig or wingsails? And which is best? BOAT explains it all...
Take a look at a modern racing yacht from above, beating to windward and heeled to the breeze, and you can see at a glance why Bermudan rigs have stood the test of time. With its fore and aft sails bladed into efficient aerodynamic shapes, a modern yacht can slice close to the wind and be driven hard. Such a sight would have been outlandish a century ago. Then, a typical trading barquentine could set 18 sails to catch light airs, but it needed a large crew to battle with canvas far out on the yards. In a modern miracle as incredible in its way as flight, today’s racing yachts can sail faster than the speed of the wind – in some cases several times faster.
A mainsail set on a single spar is an age-old concept but only in the 19th century was it adapted as the Bermudan or Marconi rig. A one-piece mainsail set on a mast without a gaff, hoisted with one halyard and controlled by one sheet, was simpler and more efficient. This revolution became the power train of pleasure yachting and racing.
But perhaps the time is coming for a re-evaluation of simpler rigs requiring fewer crew – alternatives with lower loads operated by automated systems. In an era of reduced carbon consumption, could more radical sailplans even herald a revival in sail power?
The evergreen Bermudan rig
The Bermudan rig is the all-rounder, able to perform well at all angles of sail. It is efficient upwind, while downwind the sail area can be significantly boosted with a big gennaker or spinnaker. For good reasons, it is the first choice for nearly every modern sailing yacht up to around 60 to 65 metres for cruising and regatta racing alike. At larger sizes, however, things start to become trickier, and the trade-offs get interesting.
Over the last decade, sail handling technology has steadily advanced to allow sloop rigs to grow larger and larger. “But with that comes a highly loaded rig, many tonnes of compression from tension in the rigging, and you have to build structure in the boat to accept that,” explains Paul MacDonald, founder and superyacht sales manager of Southern Spars.
“You have to have a lot of deck gear and captive winches below decks and the machinery for that. But over the years, boom furling systems and MPS [Multi Purpose Sails for downwind angles] stored on a drum, for example, have made sail handling safer.
Bill Tripp is the designer behind the 86-metre Aquijo, which broke new ground in 2015 as the world’s largest Bermudan ketch. Tripp prefers to call the rig a "sketch", a portmanteau word for a rig that is neither a sloop nor a ketch “because the main and mizzen are identical”. Even though the sailplan is divided over two masts, each spar is still a towering 90 metres above the water. Aquijo perfectly illustrates the issues involved with a Bermudan rig when scaled up.
“The sloop is great but I prefer the ‘sketch’ for sailing around the world under full control due to the desirability of a two-masted rig for reaching ability, which dominates passages, and the safety of controllable loads when sailing in all kinds of conditions miles from nowhere,” he says.
Upwind, Aquijo sets a jib, staysail, mainsail and mizzen, all in North Sails 3Di, totalling 3,821 square metres. A furling Code sail for reaching and downwind angles increases that to a vast 5,051 square metres.
While Aquijo has a crew retinue of 17, it can be controlled under sail by six or seven people. With custom winches to handle halyards and sheets, the sails can be hoisted astonishingly quickly for such a large rig. “It takes five minutes to put the main up, on average, and the main and mizzen can go up at the same time,” Tripp says. Aquijo has now sailed 100,000 nautical miles around the world and the owner is planning another circumnavigation through the Northwest Passage.
Tripp is not convinced of the wisdom of a much larger single-masted sloop rig. “If you are day sailing in the Med, a sloop would be awesome, but I am not sure if you had fewer sails you would be able to [reduce canvas] well enough. Also the mast is a windage problem when the keel is up and you are beam-to. If you are on anchor, that’s no problem but you’d have to be able to cope with being on the docks in 70 knots. The windage at 120 metres is not only more but the centre of effort is so much higher, and so the heeling loads all go up.”
However, British designer Malcolm McKeon, the name behind the high-performance, sloop-rigged carbon composite superyachts Missy and Ribelle, is pushing the sloop rig to new heights. His 85-metre design concept Apex, developed with Royal Huisman, would be the largest sloop-rigged yacht in the world. “The loads are enormous,” he admits, “but it is all scalable.”
“The big disadvantage is sail handling. The downwind sails are pretty complicated once you start hoisting and retrieving, even with drum and reel systems. It is not straightforward.” But, he adds, “I think we know the advantages of a sloop: if you want all-round performance you can’t beat it, even at the top end.”
Advantages of a clipper rig
The DynaRig has been around as a concept since the 1960s when German engineer Wilhelm Prölss devised these free-standing, rotating rigs as a fuel-saving solution for large commercial vessels. The idea was ahead of its time, so much so that its first realisation came nearly 40 years later when American owner Tom Perkins bought the residual technology and commissioned Dykstra Naval Architects to create a three-masted DynaRig for Maltese Falcon, his 88-metre Perini Navi.
The DynaRig is not as efficient upwind as the Bermudan rig, and is probably not the best solution for a yacht smaller than around 65 metres, suggests Jeroen de Vos of Dykstra. “We wouldn’t advise putting a DynaRig on a small yacht because there are other ways to manage sail handling. But on a larger yacht the DynaRig becomes an alternative because there is no rigging, no highly loaded sheets, low-tech [small] sails and no big winches.”
The beauty of the DynaRig is that its automatic systems can be handled by one or two people and, notes de Vos, “you don’t have to get out of your chair to go sailing. Maltese Falcon can sail on and off the anchor and can set 2,400 square metres of sail in six minutes. On other boats it takes six minutes to get the sail cover off.”
Damon Roberts of Magma Structures, which built the rigs for Maltese Falcon and the only other DynaRig yacht to date, the 106-metre Black Pearl, says: “You can do any manoeuvre easily; it’s like sailing a dinghy. There are no highly loaded sheets or ropes or flogging lines. You can luff up, bear away, tack and gybe at any time and really enjoy sailing the boat without any apparent fuss.”
So with all these advantages, why has the DynaRig been chosen for only two sailing superyachts? For some designers, such as Malcolm McKeon, it is partly to do with compromises imposed by the large mast tubes and bearing diameters on the internal structure and layout, “particularly in the cockpit area,” he says. He also points out that the clipper ship look is not to every owner’s taste. “Sloops are more conventional looking,” he says.
Damon Roberts says there is still development work to be done. He has teamed up with Southern Spars and, with their additional resources, expects evolution with several new projects. “These include two at the moment that are twin-masted DynaRigs,” he says. “We did quite a lot of wind tunnel work early on as we felt that was really the sweet spot for it, and people will be stunned at how efficient these are.”
The future of the wingsail
Wingsails have been around for decades too, but with their adoption by the last two America’s Cups and the confluence with foiling technology, they have undergone rapid and revolutionary development.
To date, there is no proven solution for reefing a wing that would be suitable for offshore cruising or ocean passages. As the pronounced aerodynamic “nose” at the leading edge of a wing can develop force in strong winds, they could potentially make a large yacht uncontrollable in port as well.
“How do you get rid of sail and how does [a boat] handle when caught out in heavy wind conditions – which you will be? How do you keep the angle of attack all the way up the rig and how do you handle squalls?” Roberts asks. “A mechanism to reduce sail might be easy to sketch out but it is difficult to engineer.”
Jeroen de Vos says: “The wingsails are more developed towards performance and I wouldn’t say that they are as practical as soft sails or would ever make handling easier. But if somebody wants that, why not? Reefable soft sails, wings that are inflated, hoisted panels, possibly these are applicable. The development of this area is happening very rapidly.”
Paul MacDonald of Southern Spars agrees that the time is not here yet but thinks it will come. “In reality we are in the early days of wings. For the America’s Cup, they are the most efficient way of sailing by a long shot, but with them comes handling issues, which the industry hasn’t resolved yet. But I am sure they will be in 10 years’ time. Designers such as VPLP are starting to [work on concepts] and we are going to see something that is usable and efficient and suitable for ocean work eventually,” he says. “And whatever the solution is, you imagine that it will scale.”
Looking to the future
A drive for greener superyachts could present an opportunity for sail, but perhaps it needs to be less daunting.
“There is this intimidation of sheets and backstays, and sailing is a language you don’t learn in a year,” Tripp says. “But we have a project we are doing now with a yard with some new rig technology and some soft wings that we think is going to be viable.
“We can uncomplicate sailing more. If we can win people over from motorboats it will help, but we are only winning these battles one or two at a time. We need [more] projects like Sailing Yacht A, which are something really different, and do more things better with less energy. We as architects need to elicit change.”
McKeon also sees change coming. “People are more and more concerned about keeping their image green and sails are the way to do that,” he says. “Simpler sailing systems are needed. The current generation is used to Bermudan sloops. In years to come, the traditionalists will all be gone, and maybe new people will be more accepting of [different ideas]. I think in the future we will certainly have wings.”