Headsail Sheeting

Many seperate details make a boat close-winded, but one critical factor often overlooked is the headsail sheeting setup. The most exquisite hull form with the most modern rig in the world won’t sail well to windward if the headsails can’t be trimmed in close enough to get the sails to do their work.Headsail sizes are defined in terms of their luff perpendiculars (LP) as a percentage of
Author:
Publish date:

Many seperate details make a boat close-winded, but one critical factor often overlooked is the headsail sheeting setup. The most exquisite hull form with the most modern rig in the world won’t sail well to windward if the headsails can’t be trimmed in close enough to get the sails to do their work.

headsail

Headsail sizes are defined in terms of their luff perpendiculars (LP) as a percentage of J—the horizontal distance from the headstay’s intersection with the deck or rail cap, whichever is higher, to the base of the mast on deck. A basic headsail inventory might include a 70-percent or 80-percent blade jib, a 110-percent or 120-percent heavy-air genoa, and a 150-percent light-air genoa. The maximum practical headsail size is usually around 170 percent. Any sail over 150 percent becomes increasingly difficult to tack. It also becomes nearly impossible to sheet in properly from anywhere on deck, because the lead needs to be so far aft.

The sailplan drawing at right shows how two sails are laid out, in this case an 80-percent blade jib and a 150-percent genoa. To begin the process, the designer or sailmaker draws a pair of lines at right angles to the headstay whose lengths are 80 percent and 150 percent of J. Next, a line is drawn parallel to the headstay at the aft end of these two perpendiculars. These lines define the possible positions of the clews for the two sails. The desired positions of the tack and head for each sail are then marked on the headstay, and the designer measures 40 percent up the luff of each sail and makes a tick mark. This mark (which can be as high as 45 or even 50 percent for a high-clewed jib) determines the forward end of the proper fore and aft sheet-lead line for each sail.

On the deckplan, note how guidelines have been drawn at a 7-degree and 10-degree angle radiating from the headstay chainplate. These angles represent the range of ideal sheeting angles for the two sails while sailing close-hauled. Sailing in light air requires about a 7-degree sheeting angle for maximum performance on standard headsails. A 10-degree angle is acceptable, but the boat will not be as close-winded. Heavier-air sails, like a heavy-air 110, are usually sheeted a bit freer than 7 degrees—say, 9 degrees—to open up the slot between the main and the headsail.

Picture-3

Note how the 7-degree sheeting angle for the 150 is nearly off the back of the boat. This is common and, again, a big reason why a 160- or 170-percent genoa is seldom practical. The genoa track has been laid out in plan view so that it crosses the 7-degree guideline. It also extends aft of this point and forward of the 10-degree intersection point to allow a range of trim adjustment options for different sails and different courses.

To establish the clew position for the 150, draw a perpendicular line up from the intersection of the 7-degree guideline and the genoa track on the deckplan to the deck on the sailplan. Then, draw a line from this point to the 40-percent tick mark on the luff. This line defines the correct sheet lead. To complete the sail, connect the upper and lower luff tick marks to the intersection of the sheet-lead line and the parellel 150 percent of J aft of the headstay. You’ve now got a 150-percent genoa that will sheet properly.

The blade jib is laid out in the same way. However, blade jibs and staysails can be sheeted in a bit tighter, up to 6 degrees, though 7 degrees is generally fine. On the deck plan, the blade jib is sheeted to a radiused traveler on the roof of the deckhouse. This allows the jib to be self-tacking and permits traveler control to tweak the sheet lead in and out depending on course and wind speed.

Related

TOTW_PromoSite

SAIL's Tip of the Week

Presented by Vetus-Maxwell. Got a tip? Send it to sailmail@sailmagazine.com No chafe, safe stay  If you’re leaving the boat unattended for a longish period, there’s a lot to be said for cow-hitching the shorelines, as this sailor did. They’ll never let go, and so long as the ...read more

belize600x

Charter Special: Belize

It would be hard to imagine a more secure spot than the Sunsail base on the outskirts of the beachside community of Placencia, Belize. The entire marina is protected by a robust seawall with a channel scarcely a few boatlengths across. It’s also located far enough up Placencia ...read more

DSC00247

DIY: a Top-to-Bottom Refit

I found my sailing “dream boat” in the spring of 1979 while racing on Lake St. Clair in Michigan. Everyone had heard about the hot new boat in town, and we were anxiously awaiting the appearance of this new Pearson 40. She made it to the starting line just before the race ...read more

01-oysteryachts-regattas-loropiana2016_063

Light-air Sails and How to Handle Them

In the second of a two-part series on light-air sails, Rupert Holmes looks at how today’s furling gear has revolutionized sail handling off the wind. Read part 1 here. It’s easy to look at long-distance racing yachts of 60ft and above with multiple downwind sails set on roller ...read more

HanseCharles

Video Tour: Hanse 348

“It’s a smaller-size Hanse cruiser, but with some big-boat features,” says SAIL’s Cruising Editor, Charles J. Doane. At last fall’s Annapolis Boat Show, Doane had a chance to take a close look at the new Hanse 348. Some of the boat’s highlights include under-deck galleries for ...read more

amalfitown

Charter Destination: Amalfi Coast

Prego! Weeks after returning from our Italian flotilla trip last summer, I was still feeling the relaxed atmosphere of the Amalfi Coast. It’s a Mediterranean paradise, with crystal-clear waters, charming hillside towns and cliffside villages, plenty of delicious food and wine, ...read more

image005

Inside or Outside When Sailing the ICW

Last April, my wife, Marjorie, and I decided to take our Tartan 4100, Meri, north to Maryland from her winter home in Hobe Sound, Florida. This, in turn, meant deciding whether to stay in the “Ditch” for the duration or go offshore part of the way. Although we had both been ...read more

MK1_30542

SailGP: There’s a New Sailing Series in Town

San Francisco was the venue of the biggest come-from-behind victory in the history of the America’s Cup when Oracle Team USA beat Emirates Team New Zealand in 2013, so it seems only fitting that the first American round of Larry Ellison’s new SailGP pro sailing series will be ...read more