Ask Sail: How Far to Ease Out?

Author:
Publish date:
It’s all about projecting more sail area dead downwind

It’s all about projecting more sail area dead downwind

Q: When sailing dead downwind (assume 22 knots of wind), if the main is eased out to 90 degrees relative to the wind (perpendicular to the wind) are roughly the same forces applied to the sail as to the sail if it isn’t quite out all the way, say, 75 degrees to the wind? My spreaders don’t allow me to let the main out all the way on a run, because they are swept. My friends said a 32-footer with a nearly identical sail plan and sail configuration walked right by us because my main couldn’t ease out to 90 degrees and his did. I disagree. I have a 140-percent genoa, and he had (maybe) a 150 percent headsail. Both were wing-and-wing. The only other difference was that his genoa was held open by a spin pole, mine wasn’t.

— Dana Paulson, Washington, DC

BRIAN HANCOCK REPLIES

If indeed, you are sailing dead downwind, in other words the wind direction is perpendicular to the transom of your boat, I’m afraid you are wrong. At that point of sail, it’s all about projected area, and the more area you can project, the better off you will be. Try this experiment. Sail dead downwind with your mainsail all the way out plastered up against the spreaders. Record your boatspeed. Now sheet it in so that it’s around 45 degrees and record your boatspeed. Now bring it onto the centerline and see what happens. Each degree of reduced projected sail area will reduce your boatspeed.

Note, this applies only to sailing dead downwind. As soon as you harden up onto a reach (or a beat) things change. When you are sailing dead downwind the wind is sucked around the edges of the sail and under the boom to the leeward side. However, as soon as you harden up, the wind starts to flow across your sail, in the process attaching not only to the windward side but the leeward side as well, thereby producing lift. As you start moving across the wind, you will also begin creating apparent wind, which will cause you to go faster still. With this in mind, with your swept-back spreaders you might want to consider heating the angle up a little, say, to a broad reach, which will increase your boatspeed sufficiently to more than compensate for the extra distance sailed. With any luck, when you gybe back in toward your original rhumb-line course, you’ll end up well ahead of where you would have been if you’d sailed the shorter, more direct heading.

One other thing: it’s possible that by flying their genoa on a spinnaker pole your “competition” was able to project more headsail area as well, which also contributed to them having some extra boatspeed.

Got a question for our experts? Send it to sailmail@sailmagazine.com

Related

01b-LEAD-INSET-Kirby-IMG_0077

Eight Bells: Bruce Kirby, Creator of the Laser

With 2021 drawing to a close, Laser sailors find themselves reflecting on both their class’s 50th anniversary and the passing of the man who made it all possible: Canadian designer, sailor and sailing journalist, Bruce Kirby. Kirby, who died this past July at the age of 92, ...read more

2021ROLEXIC_DF_0061

Southern Yacht Club Wins Rolex NYYC Invitational Cup

Newport, R.I. -- The 7th Rolex New York Yacht Club Invitational Cup wrapped up on Saturday after five days of highly competitive racing in an international fleet that saw the Southern Yacht Club (SYC) of New Orleans best a fleet of 19 teams from Europe, Canada, Bermuda and ...read more

DUFOUR-530_NAVIGATION_009

Boat Review: Dufour 530

Dufour Yachts seems to have shifted its strategy with the introduction of the new 530. Previously, the French builder maintained two lines: Performance and Grand Large, with the latter targeted at the cruising crowd. With the Dufour 530, however, Dufour decided to combine the ...read more

210913-11HRT-SKIPPER-PORTRAITS-VC-122

11th Hour Christens Two IMOCAs, Hits a Snag

This week has been a big one for the American-founded, sustainability-centric ocean racing team 11th Hour Racing. In addition to christening their two new boats, the team also took them out for a quick test ride—against some of the most intense IMOCA 60 skippers in the world. ...read more

01-LEAD-DSCF3091

Clewless in the Pacific

Squalls are well known to sailors who cruise the middle Latitudes. Eventually, you become complacent to their bluster. But squalls vary in magnitude, and while crossing from Tahiti to Oahu, our 47ft Custom Stevens sloop paid the price for carrying too much canvass as we were ...read more

Nigel

SAIL’s Nigel Calder Talks Electrical Systems at Trawlerfest Baltimore

At the upcoming Trawlerfest Baltimore, set for Sept. 29-Oct. 3, SAIL magazine regular contributor Nigel Calder will give the low down on electrical systems as part of the show’s seminar series.  The talk will be Saturday, October 2 at 9am. Electrical systems are now the number ...read more

5ae5b8ce-3113-4236-927b-f795be4ae091

Bitter End Yacht Club Announces Reopening

Four years after being decimated by Hurricanes Irma and Maria, the Bitter End Yacht Club is set to reopen for the Winter 2022 season. Hailed as one of the best anchorages in the Caribbean and built by sailors, for sailors, this island outpost in the BVI has been a favorite with ...read more

01-LEAD-'21.05.01_Jay-&-Mira

Cruising: Bluewater Pollywogs

Bluewater sailing is 25 percent actually sailing and 75 percent learning how to live on a boat at sea, in constant motion and with no chance to get off the roller coaster. I cannot over-emphasize how difficult normal daily functions become at sea, even on nice, calm days. ...read more