October 11, 2012

No comfort under 40

A MAN I ONCE KNEW wanted very badly to sail around the world with his wife and young family of a seven-year-old boy and a five-year-old daughter. But his wife was worried about seasickness and wanted to be assured that any sailboat they bought would be “comfortable in a choppy sea.” So he asked me what I thought. I told him not to expect much comfort in a choppy sea in any boat under 40 feet, and I’m afraid that dashed his hopes of a circumnavigation because he couldn’t afford a boat that big.

It’s an unfortunate fact that the very qualities necessary to ensure survival, such as maximum buoyancy and fast reaction to changing water levels, result in the kind of quick, jerky motion that causes seasickness and difficulty in moving about — sometimes even difficulty in staying put.

That said, some designs are kinder to humans than others. The well-known naval architect Ted Brewer, who invented a formula for a “comfort ratio,” says that quickness of motion, or “corkiness,” is determined mainly by two factors: the beam of the hull and the area of the waterline.

What this translates to is that it’s more comfortable to sail in a boat that’s comparatively narrower, deeper, and heavier than another of the same length.

Most classic full-keel designs fulfill those requirements. They’re slightly slower to react to waves and swells because of their increased inertia. They’re less likely to be capsized by a breaking wave and it’s safer to work on the deck of such a boat, though they may be wetter. Comfort naturally increases with size, but it increases more quickly with displacement than with length.

So there you have it. Comfort is subjective. The very word means different things to different people, and the amount of discomfort the human body can endure is quite remarkable. Most people get used to the motion of a sailboat at sea sooner or later, and the arbiter then, as the boats become smaller and lighter in displacement, is whether you can actually endure the physical punishment of being bodily thrown around in bad weather.

Judging by the number of people sailing around the world in boats of 30 feet and under, it’s not a problem if you take the calmer tradewind routes and pick your seasons with some forethought.

Today’s Thought
It is often a comfort to shift one’s position and be bruised in a new place.
— Washington Irving, Tales of a Traveller

“Dad, I need a car.”
“What? You think cars grow on trees?”
“Heck no, Dad. Everyone knows they come from automobile plants.”

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

1 comment:

Jack said...

I read a book some years ago, written by an author of Germanic roots but then living in Canada I believe, sorry I can't remember the book or his name. He was of the opinion that if one wished to circumnavigate this planet, a wife who wasn't fully "on board" with this plan, was a serious demand on your time. He answer, jettison the wife.
Harsh you may say, but I suppose it's a point of view.
If worrying about seasickness scuttles a dream, your dream is not a dream, it's just a passing notion, I would suggest in my humble opinion.
I hope he does turn this notion into reality. He could find a ship mate who hasn't the propensity to suffer from motion sickness, but me thinks another problem would then hinder him casting off, but that's just speculation on my part.