May 24, 2011

Heavy-weather tactics

A COMMENT FROM David Browne says:

“I have read your analysis of sea anchors in The Seaworthy Offshore Sailboat, and your comments concerning the Pardeys’ technique, and have read the Pardeys’ book on storm tactics many times, trying to find something to support my skepticism of what sounds like overly simplistic generalizations (i.e., carrying a trysail in 70-plus knots of wind while lying peacefully to a sea anchor) and their statement that a sea anchor off the bow is the last resort needed to survive basically any storm. I think both drogues and sea anchors have their usefulness but neither is a blanket tool of last resort. Any thoughts?”

Plenty of thoughts, David, but few specific answers, for the reason that every boat handles differently and every storm’s wave pattern is different. You’re right, there are no simple generalizations. You can’t be dogmatic about one particular method being the right one for every boat in every storm.

The Pardeys have made a lot of noise about the benefits of a sea anchor, but they themselves survived a typhoon (just 80 miles from its center) by heaving to under a reefed mainsail only, with the helm lashed a-lee. No sea anchor was involved. They seem to have used the sea anchor occasionally to stop forward motion while hove-to under a reefed mainsail only, thus keeping the boat directly downwind of the beneficial “slick” caused by the keel’s being dragged sideways through the water, a turbulence that apparently causes waves to break farther to windward and expend their energy before they meet the boat. Incidentally, their nylon “sea anchor” is 8-feet in diameter and porous. It’s far smaller than a true sea anchor would be for their size of yacht, so I regard it as more of a large drogue than a proper sea anchor. See here:

The late Adlard Coles, a small-boat racer with extensive experience of sailing in storms, experimented with a sea anchor on 30 fathoms of nylon line in the famous Santander Race storm. He streamed it from the bow and it did no good. His boat, the well-known Cohoe, continued to lie broadside on. So he took the line to the stern and it “seemed to have steadying effect.” With no sails up, though, the motion was still “wild in the extreme” while she ran before the seas. The sea was violent and large, and the cockpit was often a foot or two under water from heads of seas and driving spray, but Cohoe behaved very well. When the wind dropped slightly and they decided to make sail, two crew heaved on the long warp leading to the sea anchor. “With the final heave they discovered the truth: there was nothing at its end. The sea anchor had gone in the night and no one noticed any difference.”

Many, many small sailboats have endured “ordinary” gales safely by heaving-to, that is getting the boat to lie at an angle of between 45 and 60 degrees bows-on to the waves. Even more, I suspect, simply lie a-hull, that is, they take in all sail, lash the helm a-lee and leave her to her own devices. In building winds, though, there comes a time when waves will start to pick her up and throw her sideways, down onto her lee side. Then it’s time to run before the wind.

Adlard Coles, in his book Heavy Weather Sailing, advises: “For those who are in doubt, especially when caught out in ordinary gales, I recommend the well-tried expedient of streaming warps ... What I think is clear is that you must either run fast enough to give absolute control so that the boat will respond to a flick of the wheel or tiller, or else slow down, when warps will have to be streamed to steady the stern to the seas.”

If that doesn’t work and the wind is still building, you may have to resort to Moitessier’s trick of taking large breakers 20 degrees on the stern and running free without warps. He felt that the warps were holding him back so much that he couldn’t maneuver out of the way of the biggest waves. He also pointed out that a boat held back by warps or drogues will be punished more severely by plunging breakers than one that can respond by fleeing forward and relieving much of the pressure.

But in the end everything depends on the design of the boat, above and below the water. Multihulls and other shallow-bodied sailboats and powerboats might lie quietly to a sea anchor bows-on to the waves, but most sea-going sailboats will not.

It’s extremely difficult to find good simple advice on this subject because very few people actually encounter survival storms, and what worked for their boats might not work for yours. So the real answer is to read as much as you can of other people’s adventures while keeping an open mind and watching for their natural bias with a healthy skepticism. Be aware of the many possibilities, gain experience by experimenting in your own boat, and work out for yourself a set of general principles to apply when the time comes.

Today’s Thought
No one can with safety expose himself often to danger: The man who has often escaped is caught at last.
— Seneca, Hercules Furens.

Boaters’ Rules of Thumb, #203
A long-established rule of thumb is that a sailboat’s tiller shouldn’t break if a 200-pound sailor falls on it. I have never seen any indication of the maximum height from which that sailor should fall, though. Perhaps it would be wise to request any crewmember heavier than 200 pounds to keep well clear of the tiller when he or she is likely to fall down.

“Darling, will you still love me after we’re married?”
“Sure, why not? I’ve always been partial to married women.”

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

1 comment:

John Vigor said...

To Matt Marsh: Thanks for your comment. See the next column.


John V.