September 1, 2015

This is how we trim sails

MANY YEARS AGO, when I was being taught how to teach people to sail, my instructor, Captain Corinne Mattingley, played the part of a puzzled beginner. She asked: “Why does the jib have two sheets when the mainsail only has one?”

I was taken aback by that simple question. I ummed and aahed while my brain struggled to pull itself together. Eventually she took pity on me. “The mast is in the way of the jib sheets,” she explained. “You need one on each side.”

Well, I knew that, of course. Just never thought about it. People like me who have sailed from childhood often sail by instinct without knowing the reasons for things. For instance, it took me a long time to figure out the answer to the question: How do you know when your sails are correctly trimmed?

The point I had always overlooked here is that there are two “modes” of sailing. The first is when you’re trying to sail to windward as efficiently as you can. The second is when you’re not trying to sail to windward as efficiently as you can.

In the first case, you trim your sails for a beat, and then you cleat them and steer the boat left and right to keep the sails filled correctly. You luff or fall off as the case may be, steering a weaving course as the wind direction changes. In other words, you’re trimming the sails by moving the rudder.

In the second case, on all courses from a close fetch to running dead before the wind, you steer the boat steadily at the spot you’re aiming for and you keep changing the trim of the sails to suit the changing wind. Now you’re trimming the sails by tightening or loosening the sheets.

So when you’re beating you constantly steer the boat to suit the wind; and when you’re sailing free you sail a steady course and constantly trim the sails in or out to suit the wind.

In practice, of course, most of us don’t bother to keep fine-trimming the sails because the wind usually tends to switch back and forth slightly, so we trim for the average. But if you want to race it’s important to react more quickly to wind changes, and even if you’re cruising it’s reassuring to know the theory — so you could go faster if you really wanted to.

Today’s Thought
We’re drowning in information and starving for knowledge.
— Rutherford D. Rogers, librarian, Yale

Here’s some advice for the semi-adventurous: Don't join dangerous cults; practice safe sects.


Eric said...

I like the thought for today but, shouldn't Dr. Rogers (I assume he's a Dr. being a librarian at Yale) have kept to the water reference and stated;
We're drowning in information and "dehydrated by lack of" knowledge?
What do I know, I'm not a Yale librarian.

Kenneth Sherwood said...

Or there are two job sheets because there is no boom--on most jibs. A boomless main without a traveller on a traditional boat would also have two sheets, no ?