The Ul­ti­mate Hy­brid

Mo­tor­sail­ing makes a come­back with the sail-as­sisted su­pery­acht.

Yachts International - - Contents -

In 1967

, a Ger­man hy­draulics en­gi­neer named Wil­helm Prölss pro­posed a square-rigged bulk car­rier with six steel tri­pod masts. The in­no­va­tive ves­sel was de­signed as a fuel-sav­ing so­lu­tion for com­mer­cial ship­ping in re­sponse to the loom­ing OPEC oil cri­sis, but decades passed be­fore the ad­vent of light­weight com­pos­ite ma­te­ri­als, ad­vanced hy­draulics and op­tic sen­sors meant his the­ory could be put into prac­tice. It took nearly 40 years be­fore the ven­ture cap­i­tal­ist Tom Perkins latched onto the Dy­naRig con­cept for his rad­i­cal Perini Navi sail­ing yacht, the 289-foot (88-me­ter) Mal­tese Fal­con.

Each suc­ces­sive rise in oil prices has led to re­newed in­ter­est in sail-as­sist tech­nolo­gies. SkySails in Ger­many, for ex­am­ple, has tested high-alti­tude kites at­tached to the bows of cargo ves­sels with pos­i­tive re­sults. But only in re­cent years, as yacht own­ers come un­der in­creas­ing pressure to be seen as green, have de­sign­ers started de­vis­ing hy­brid su­pery­acht con­cepts that har­ness the wind to re­duce fuel con­sump­tion.

Oliver Stacey is a Bri­tish de­signer who honed his skills work­ing along­side in­dus­try vet­eran Martin Fran­cis. To­gether with naval ar­chi­tects from BMT Nigel Gee, Stacey has de­vel­oped a 262-foot (80-me­ter) sail-as­sisted ex­plorer con­cept called Norse, after the Vik­ing long­boats that in­spired it.

“De­spite ap­pear­ances, Norse is a hy­brid elec­tric mo­to­ry­acht that uses the wind as a se­condary source of power,” Stacey says. “Sail-as­sist is a read­ily avail­able tech­nol­ogy that, in the right con­di­tions, can save on fuel con­sump­tion at least 20 per­cent.”

The ves­sel’s low-as­pect sailplan has three iden­ti­cal wing masts and in-boom furl­ing main­sails, a con­fig­u­ra­tion that en­hances re­li­a­bil­ity and flex­i­bil­ity while re­quir­ing min­i­mum man­power for han­dling. Sail-as­sist mode would be en­gaged to re­duce fuel con­sump­tion dur­ing long-dis­tance pas­sage­mak­ing, and is ex­pected to im­prove the ves­sel’s mo­tion.

“One of the orig­i­nal themes that we wanted to ad­dress was ecosen­si­tiv­ity,” says James Roy, yacht de­sign di­rec­tor at BMT Nigel Gee. “When we ac­tu­ally sat down and thought [about] how we could achieve that, you can’t get away from the fact that us­ing the wind was the ob­vi­ous so­lu­tion. But we didn’t just want to de­sign a sail­ing yacht. In a way, this is the ul­ti­mate hy­brid.”

Norse is de­signed with mul­ti­ple cli­mates in mind, but would be built to Po­lar Class com­pli­ance for cruis­ing to re­mote des­ti­na­tions and higher lat­i­tudes. The yacht would have a shal­low draft, dy­namic po­si­tion­ing for in­creased ma­neu­ver­abil­ity in re­stricted ar­eas, and zero-dis­charge ca­pa­bil­ity for en­vi­ron­men­tally sen­si­tive ar­eas.

Break­ing with con­ven­tion, Stacey says that only the su­per­struc­ture would be fully faired and painted, with the alu­minum hull un­filled and un­painted. An A-frame crane in­te­grated into the stern could launch and re­trieve a sea­plane to ex­tend the range of ex­plo­ration.

VPLP De­sign in France has come up with a sim­i­lar con­cept. First pro­posed in 2015, the 282-foot (86-me­ter) Ko­morebi ex­plorer—named after the Ja­panese word to de­scribe sun­light fil­ter­ing through the leaves of trees—draws on a sta­bi­lized mono­hull

plat­form, hy­brid elec­tric propul­sion and au­to­mated wing sails that can drive the yacht at 15 knots with 20 knots of wind, re­duc­ing fuel con­sump­tion by around 30 per­cent.

“These are not pure sail­ing yachts or pure power ves­sels,” says VPLP co-founder Marc Van Peteghem. “You can use power or sail sep­a­rately, but most of the time you would prob­a­bly use both to­gether. As an ex­plorer, the idea is to en­hance range and au­ton­omy rather than speed.”

VPLP’s in­ter­est in rigid wing sails be­gan in 2010, when it col­lab­o­rated with BMW Or­a­cle Rac­ing, win­ner of the 33rd Amer­ica’s Cup. De­spite the su­pe­rior aero­dy­namic efficiency of rigid wing sails, they can­not be reefed or furled like fab­ric sails to re­duce their sur­face area. To over­come this ob­sta­cle, the stu­dio is pi­o­neer­ing a new soft-wing sail tech­nol­ogy called Ocean­wings, which also can serve as a sail-as­sist so­lu­tion.

En­tirely au­to­mated, self-sup­port­ing and ro­tat­ing through 360 de­grees, Ocean­wings adapts its an­gle of in­ci­dence to the point of sail to en­sure op­ti­mal propul­sion. Power is man­aged by trim­ming cam­ber

and twist. Ac­cord­ing to VPLP, Ocean­wings is ef­fi­cient to the point of halv­ing the sur­face area re­quired to pro­pel a ves­sel un­der con­ven­tional sail. The de­sign stu­dio ini­tially de­vel­oped the tech­nol­ogy with com­mer­cial ship­ping in mind, but Van Peteghem says the con­cept is more likely to be picked up by eco-conscious su­pery­acht clients. His team has in­stalled the Ocean­wings sys­tem on a 23-foot (7-me­ter) tri­maran pro­to­type to fine-tune per­for­mance mod­els.

“Of course, it de­pends on how you want to use your yacht, but it’s also a ques­tion of re­spon­si­bil­ity and im­age,” says Van Peteghem, who is tak­ing ship­yard quotes for a 305-foot (93-me­ter) project based on the Ko­morebi con­cept. “I be­lieve it’s time to pro­pose more eco-sen­si­tive so­lu­tions to the power mar­ket. A lot of to­day’s own­ers don’t want, or sim­ply can’t af­ford, to be seen as the bad guys, and I think it’s our duty as de­sign­ers to start mov­ing in the right di­rec­tion.”

You could ar­gue that sail-as­sist is just an­other name for mo­tor­sail­ing, and you wouldn’t be far wrong. Un­for­tu­nately, the term is as­so­ci­ated with ves­sels that are too un­der-can­vassed and heavy to move at any­thing like hull speed in av­er­age wind con­di­tions without en­gine as­sis­tance. Laurent Giles Naval Ar­chi­tects in the U.K. took this crit­i­cism to heart when de­sign­ing the 360-foot (110-me­ter), four-masted At­las con­cept in col­lab­o­ra­tion with H2 Yacht De­sign.

At first glance, At­las looks like other sail-as­sist projects, but Steve Wal­lis, co-di­rec­tor at Laurent Giles, prefers to call it a meg­amo­tor­sailer that can sail as fast as it can mo­tor. Us­ing a hy­brid elec­tric power plant that can store elec­tri­cal en­ergy, the ves­sel could mo­tor in ex­cess of 18 knots. Un­der sail in a fresh breeze and de­pend­ing on the wind an­gle, she could cruise at com­pa­ra­ble speeds. More­over, mul­ti­ple sails mean their in­di­vid­ual sizes would be rel­a­tively small and, com­bined with au­to­mated sail han­dling, could be op­er­ated with a con­ven­tional num­ber of crew. Cruis­ing with sails alone would elim­i­nate all but ho­tel loads from the power plant, with the ad­van­tage of near-silent oper­a­tion.

“Sail-as­sist or mo­tor­sail­ing is some­thing the su­pery­acht in­dus­try has not re­ally wo­ken up to, and the po­ten­tial to use the wind to either re­duce power re­quire­ments for a given speed or elim­i­nate it

com­pletely most of the time—apart from gen­er­a­tors—is un­der­ap­pre­ci­ated,” Wal­lis says. “I think part of the prob­lem is that mo­to­ry­acht own­ers dis­count sails be­cause they don’t un­der­stand them, are wor­ried by ex­tra crew re­quire­ments and don’t like heel­ing over. On the other hand, sail­ing yacht own­ers prob­a­bly want per­for­mance and think mo­tor­sail­ers are old clunkers.”

The fact is, even cruiser­racer sail­ing yachts spend rel­a­tively lit­tle time un­der sail alone, es­pe­cially dur­ing long cross­ings with re­duced crew. Too lit­tle wind and the yachts make heavy head­way; too much and they risk break­ing ex­pen­sive spars and sails.

A sail­as­sisted ves­sel not only pro­vides much less heel­ing with the in­te­rior vol­ume and deck space of a mo­to­ry­acht, but it also of­fers im­age­conscious own­ers the op­por­tu­nity to flaunt their green cre­den­tials.

Who knows? The con­cept just might turn the mo­tor­sailer into the new icon of cool.

And hoisted onto the aft deck.

The plane is at­tached to the crane ...

Norse uses an in­te­grated A-frame crane for sea­plane op­er­a­tions.

The tran­som ramp is low­ered ...

Above: At­las, the 360-foot mega-mo­tor­sailer con­cept from Laurent Giles Naval Ar­chi­tects and H2 Yacht De­sign.

above: A bird’s-eye view of the four-masted At­las con­cept.

above and left: VPLP is de­vel­op­ing an au­to­mated wing sail sys­tem for its Ko­morebi con­cept, a 282-foot tri­maran.

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