Sloop vs. Ketch: Which is Better?

22 December 2008 By Oliver Dewar

Perhaps the earliest recorded “review” of a ketch rig dates from 1625. John Glanville, secretary to Sir Edward Cecil, Admiral of the English Fleet, wrote “[Ketches] being short and round built, be very apt to turn up and down,” he observed. “And useful to go to and fro, and to carry messages between ship and shore almost with any wind.”

Glanville – an inveterate landlubber despite his navy status – attributes the ketch’s manoeuvrability to the vessel’s size and shape; he completely overlooks any benefits of the rig.

In basic terms, a ketch can carry more sail area than a sloop, but with smaller sails and a greater range of combinations that are easily managed shorthanded. As Glanville noted, a ketch can “turn up and down” (upwind and downwind), “go to and fro” (tacking, presumably) “almost with any wind” (in all conditions). His final remark is the key to the ketch rig; it’s ideal for offshore, long-distance cruising.

On a large sloop, having to reduce a large mainsail rapidly in strong winds can contribute to an uncomfortable environment on board. Whereas with a ketch arrangement, the total sail area can be gradually moderated through a variety of combinations without drastically reducing speed; or the sail area can be reduced dramatically by reefing or dropping the smaller mainsail or dispensing with the mizzen sail.

There is, though, a potential performance disparity between sloops and ketches. Upwind, a sloop is normally the rig of choice; the smaller mainsail on a ketch of an equivalent size can spill turbulent, dirty air on the mizzen, making the sail inefficient and consequently stalling boat speed. Off-wind, however, the ketch has numerous advantages with its capability of carrying genoa, mainsail, mizzen staysail and mizzen for reaching in good conditions, or just jib and mizzen in stronger weather.

In running conditions that may be too hard to carry a spinnaker, a sloop rig’s genoa is often blocked by the larger mainsail, while a ketch’s mainsail and mizzen can work together without the aft sail disturbing the mainsail. Ketches triumphed in the predominantly downwind Whitbread Round the World Race and the first nonstop, solo, circumnavigation race, the Golden Globe, in 1968-69.

Over the past few years, Ed Dubois has designed both large ketches and sloops. “When the owners of [51-meter, 2008 launch] Mandango said they wanted a ketch, it was due to the fact that they just liked the look of the ketch rig,” recalls Dubois. “Somehow, Mandango just looks a bigger boat than her sloop sisters. The extra rig seems to help.”

However, historically, the general trend towards sloops seems inevitable: “The reason multi-mast rigs came into being from the very beginning was the need to have the sails in manhandle-able parcels as boats increased in size,” explains Dubois. “Then as sailing ship owners tried to compete with steamships, they attempted to cut costs by reducing crew,” he continues. “So, crews got smaller on windjammers as the boats got more and more masts. There were seven-masted schooners being crewed by twelve people, which is quite extraordinary.”

With the decline in sail powered, commercial shipping, Dubois believes 20th century technology revitalized the practical aspects of big, single mast sailboats, making very large sloops a feasible option.

“As soon as the sailing superyacht thing got going in the 80s and 90s, the Kiwis, the Dutch and to a certain extent the British started producing hydraulic furling gear and winches, so you could handle sails and hoist sails with very few people,” says Dubois. Instantaneously, the crew number/sail management equation was altered. “There’s now no real reason to split the rig up into a ketch or schooner anymore. So, a sloop is fine,” says Dubois.

Although Dubois says that mast-building methods and materials are now acceptable for building 80-meter masts, there are physical obstacles for big sloops: namely the Mubarak Peace Bridge across the Suez Canal with a height of 70 meters and the 61-meter-high Bridge of the Americas over the Panama Canal.

“The new [58-meter] Kokomo won’t fit under the Panama bridge and we’re designing a sixty-six-meter sloop with a seventy-eight-meter mast that won’t fit under it either,” says Dubois.

Fortunately, this height disadvantage does not require switching to a ketch rig with shorter masts. “Owners just aren’t concerned about the issue,” says Dubois. “They just say, ‘Well, we’ll go round Cape Horn. What’s the big deal?’”

Although the upwind-downwind performance variation between sloops and ketches remains, technology now permits bigger, safer masts for sloops and the deciding factor appears to rely on personal taste.

“Most people are favoring sloops on aesthetic grounds,” continues Dubois. “I think many people like the idea of that very slender, beautiful, single mast. If I was making a choice, I don’t now what I’d do, to be honest. It’s a really difficult question.”

What would you build? For more rigging trends, check out the Radical Rigging feature in the Dockwalk January 2009 issue.