January 27, 2011

Is a third reef necessary?

EVERY NOW AND THEN some cruising sailor gets caught out in a gale and comes home wondering out loud if the mainsail should have a third reef. The advice comes pouring in from all sides, and it’s usually contradictory and confusing.

Racing skippers will tell you they never reef. Well, hardly ever. But it’s different for them. They don’t care if their mainsails flog themselves to bits on the beat. They’re going to buy new sails next season anyhow. And they’ve got large muscular crews with highly developed clinging powers, so they won’t fall overboard when the boat broaches and the mast hits the water.

Some sailmakers aren’t much use, either. A contributor to one bulletin board I read recently said his sailmaker simply refused to put a third reef in the mainsail for his 26-foot full-keeler. “He said the extra sailcloth and grommets involved would screw up my main's light-air performance. I would add too much ‘stuff’ (weight, hardware, etc.) up high, where I don't want it. And would not let the leech open up properly in light air.” Well, to put it delicately, this is pure poppycock, of course. That sailmaker has been brain-washed by racing skippers.

However, I personally don’t believe a boat of average displacement under 35 feet in length is going to benefit from a third reef in storm conditions in the open ocean. Perhaps that reef might help in calm water near shore, but it’s not going to generate enough power to push a boat to windward in the big seas a storm generates.

My preference is for two oversized reefs on a boat of that size, and when things become too hectic for the second reef you have three choices: lie a-hull, heave to under a main trysail, or run off, either under a storm jib or under bare poles.

Now when it comes to bigger boats, a third reef can make sense. The difference here is that a big boat not only finds it easier to carry its way against big waves, but it also can carry comparatively more sail to drive it to windward. That’s because stability (hence the power to carry sail) increases as a cube of the boat’s length, while the force of the wind increases only as a square of its speed.

So, while a 40-footer is only 62 percent longer than a 25-footer, it can carry 410 percent more sail for the same degree of stability. That means a third reef in a 40-footer is comparatively much bigger than a third reef in a 25-footer, and is thus able to generate a comparatively greater amount of power.

I once had a third reef added to my main on a 31-foot heavy displacement sloop. I went through seven gales with that boat and never used my third reef once. I thought it would substitute for a main trysail, but by the time the third reef was down, the center of effort had moved too far forward. The heavy wind against the mast and rigging simply blew the bows off and she wouldn’t heave to. That’s what a trysail is all about. It gets sail area well aft, so the stern will blow to leeward and the boat will end up lying pointing at an angle of 60 or 70 degrees off the oncoming wind and waves. That’s the safest, most comfortable position until the boat starts to be picked up bodily and hurled down sideways.

Finally, let me repeat the three basic rules of thumb about the timing of reefing:
1. Reef before you have to.
2. When sailing downwind, reef in the same wind speed you would if you were beating. (Not easy either to judge or to do, but very necessary.)
3. When in doubt, go straight to the double reef.

Today’s Thought
The tempest’s howl, it soothes my soul,
My griefs it seems to join;
The leafless trees my fancy please,
Their fate resembles mine.
— Burns, Winter: A Dirge

Boaters’ Rules of Thumb, #152
WHEN to reef? Before you lose control. On the wind, the signs are pretty obvious: sidedecks awash, dreadful weather helm, and lack of response to the helm. Downwind, watch for prolonged surfing and a sloppy, dead feeling to the helm when a waves passes underneath the stern. Time to slow down.

Après moi, le déluge
I’M PLEASED and astonished to report that new Followers have been flocking around in hordes to compensate for the fickle Follower who left me for greener pastures (long may he rot). The Follower count is now up to a record 37. I am a happy man.

“Hey, do me a favor, willya? Stick your head out the window and see if my turn signals are working.”
“Well, are they working?”
“Yes — no — yes — no — yes — no —”

(Drop by every Monday, Wednesday, and Friday, for a new Mainly about Boats column.)


Bursledon Blogger said...

our Van de stadt 34 had three reefs,and hove to perfectly for 48 hours in a mid Atlantic gale, was also useful sheeted right in hard as a steadying sail with twin headsails going down win, would stop the rolling.

Your experience with a Nic 31 probably says more about the boat than the sails - having tried both types I'm convinced that medium to light displacement and traditional hull from i.e narrow transom is the best all round cruising boat. i'm sure others will disagree

John Vigor said...

Hi Bursledon B:

Yes, I would agree with you that moderation in all respects is the way to go with a cruising boat. The extremes of very light displacement and very heavy displacement often have more cons than pros. And Van de Stadt knew what he was doing when he designed the 34. Very nice boat.
Have to say, though, that I'm always astonished when people in foreign countries reveal what they know about me. It wasn't actually a Nicholson 31 that I owned, but it was a very close relative, a Performance 31 designed by Angelo Lavranos.


John V.

Ben said...

My 26 footer ended up with 4 reefs (long story), One to many, but I used the 4th reef alot around Wellington, across the Tasman and then around Tassie. (3.5 hp outboard so really needed to sail in strong winds).

I delivered a 28 footer back to NZ with only two deep reefs... couldn't get the groove right, either too much sail or not enough, really wished I had three moderate reefs.

Saying that neither boat had roller reefing headsails so I used the main as my throttle. I reef and unreef often, sometimes a couple of times per watch to keep in that nice comfey groove just below hull speed were the windvane works best.

Give me three reefs on any sized sloop or cutter designed for offshore.

I enjoy your writing John, and love the black box theory, I apply it alot in real life, it's probably saved me a few times..



John Vigor said...

Hi Ben:

Yes, most of us are inclined not to fine-tune the exact amount of reef, as you do with such dedication. Most of us are content to be a bit underpowered and get nowhere fast. But you're absolutely right about the need for a good amount of sail area in strong winds, especially in the tough seas you seem to be sailing in, between OZ and NZ. Your frequent reefing and unreefing is certainly earning you points in the black box.

Cheers and best wishes,

John V.

s/v Windward said...

Windward, my Herreshoff 26 (OK, it's a Chrysler, perhaps the Rodney Dangerfield of sailboats, but Halsey was the hired gun and she sails very, very well) has three fairly deep reef points, each reducing the 26 ft luff by 4 ft.

On my local mountain lake I'm able to use the 3rd reef a couple of times each winter, when winds are 20-25 kt or more. I don't have pretenses to sailing offshore, but do sail on North Carolina's Pamlico Sound, and up to 25 miles offshore (but inside the gulf stream) from Ocracoke to Cape Fear. I was thankful for the 3rd reef a couple of years ago on Pamlico Sound during several days of small craft advisories, making 5.4 to 5.8 kt upwind using that and about 40 sq ft of headsail. The waves were only 4-6 feet despite the 25-30 kt breeze, so there was no problem getting enough clear air to move the boat. Downwind that sail combination kept me above hull speed most of the time, and I could not have carried more sail safely.

Sailing 20-25 miles offshore south of Cape Lookout, I have found it challenging to keep the boat moving when heavily reefed, and have had to carry more sail than I anticipated. I've had the luxury (good fortune? good sense?) of avoiding gale conditions there, so don't yet know whether the third reef would be effective for me then.