July 21, 2011

Survival in hurricanes

BOATERS ON THE EAST COAST are mentally preparing themselves for another hurricane season. One owner of a 35-foot sailboat who often crosses over to the Bahamas wants to know if sailboats can survive hurricanes. “How high do the waves get, and how do yachts handle them?” he asks.

Well, certainly, many sailboats have survived hurricanes. For example, Atom, a 30-foot Tahiti ketch sailed by Jean Gau, a New York chef, survived a hurricane that sank a sail-training ship, a large square-rigger, not far away.

But it’s misleading to say a boat survived a hurricane. There are boats and there are hurricanes, and no two are the same. To a great extent, it depends on how far the boat is from the center of the hurricane, and whether she is in the safe quadrant or the dangerous quadrant.

As for the height of waves, here’s what Captain Edwin Harding, author of Heavy Weather Guide, has to say about it: Waves of 35 to 40 feet are not uncommon in an average hurricane. In giant storms they can reach to 50 feet or higher.

How do you deal with waves that high? It depends on the size of the breaking crests, the characteristics of your boat, and where the nearest land lies, whether you heave to, lie ahull, or run off. In extremis, there doesn’t seem much you can do other than take down all sail, slide the companionway tightly shut, and climb into a bunk with a lee cloth to prevent your being flung out. Any jetting crest that is taller than 55 percent of the overall length of your boat will capsize you if it hits you broadside on — a 19-foot crest if you’re aboard a 35-footer. That’s a huge plunging breaker, admittedly, but they do happen and if the wind is blowing against the Gulf Stream, things can get even worse, and very quickly.

So if I were crossing to the Bahamas and back I’d keep a good eye on the weather forecasts. I never want to be at sea in the teeth of a hurricane.

Today’s Thought
Let him who knows not how to pray go to sea.
John Ray, English Proverbs.

Boaters’ Rules of Thumb, #225
The apparent wind direction changes by between 5 and 8 degrees from the bottom of the mast to the top, depending, of course, on high your mast is. The rule of thumb, therefore, is that the leech at the head of the sail should lie further off the wind than the leech near the clew.

Mary had a little watch,
She swallowed it one day,
So now she’s taking purgatives
To pass the time away.

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

1 comment:

Micky-T said...

I was out in the Gulf Stream during "the no name storm"(91,92?)as crew on a delivery to Antigua, a fifty five foot boat well appointed. Our wind speed indicater was "pegged" to the pin at 50 knots for two full days. I still describe the seas as high as telephone poles (50')and just about as far apart. The captain chose to maintain headway into the seas(motoring with a bedsheet of main rolled out)because we could hold our position (somewhat) and not lose to much ground southing, because of course there was a charter scheduled in St Lucia.

We took a serious beating from breaking crests but all over the bow and they ran the length of the boat. The boat took it fine but we lost parts of a dingy(floorboards) that was lashed forward along with a windsurfer, and of course they did damage as they were swept aft and took out a dorade box on the cabin top. While getting the kid set up below with the emergency bilge pump I got to witness how much water comes in a 4" hole as we took a breaking crest. I describe that as a 55 gal drum being filled in about 5 seconds.

Back on deck, the captain and I lashed and tethered managed to get out there and duct tape the hole. Yes, quality duct tape sticks to fiberglass in salt water.

We made Bermuda OK, hadn't had my foul weather off or even opened, for almost three days. Yes, sometimes there is no time for even zippers.