Mainsail Trim Points

When I learned to trim a mainsail, the instructions were pretty simple: Trim
the boom inside the rail, steer up into the wind, and keep an eye on
the sail just behind the mast for the first signs of a luff. And don't
cleat the main, or you might get wet.

Over my years of
racing, I've learned to watch the angle of the top batten to try to
point as close to the wind as possible. Sighting from under the boom, I
trim the sheet until the two are parallel, except in waves or heavy
winds, when it's much faster to let the sail twist open a little. This
approach has worked on cruising boats I've sailed, too, but reading
Jeremy McGeary's story on mainsails ("More Powerful Mains, Less Muscle
to Manage Them"), I noticed a problem. On many new cruising mains, my
trusty top batten no longer exists. These new sails can do lots of
clever tricks--they can flake, they roll inside the boom, or they roll
in the mast. But a rapidly increasing number are sold for in-mast
furlers and have vertical battens or no battens at all.

With
any main, you can still sight up the leech to see how tightly the sail
is trimmed, then experiment with different settings while watching wind
and speed instruments. This is a good way to improve your trimming eye,
unless you fall prey to what may be the ultimate obstacle to good trim
for a mainsail--a difficulty I encountered last year on a bareboat
charter. Standing at the wheel with the bimini up, I couldn't see any
part of the mainsail. Sure, I could engage the wheel brake or the
autopilot, lean out over the stern pulpit, and have a look, but that
got old in a hurry. Fortunately, the solution to this is easy, and it
was in evidence on nearly every boat with a pilothouse, hard top, or
bimini at last winter's Miami Boat Show: They all had windows above the
helmsman's head.

How high your boat will point and how fast it
will sail upwind depend on more than its mainsail. At least as
important are stability, underbody shape, and headsail sheeting angles,
not to mention good sails and a clean bottom. But the fundamental goal
remains the same for all boats: balance the helm so the rudder works as
little as possible. On a racecourse, a balanced helm is plain faster.
For anyone else, it just makes sense not to fight the wheel, and it's
easier on the autopilot, too.

As in life, when I sail I'm
always looking for tips on improving balance. If the bow falls off when
I ease the mainsheet in a puff, I know that's a sign of leeward helm,
so maybe I should tighten the boom vang to help the leech hold its
shape. This can be done even if you have a solid, non-adjustable vang
with an in-boom furler; according to Dave Anderson of Schaefer, which
makes the Boom Furler, you can just "turn the mandrel [furler] a
little."

Want to solve the more common problem of weather
helm? I start by tightening the outhaul, although I've learned the hard
way that this has its limits. A tired outhaul can fail if you're too
enthusiastic on the winch handle--but even that would be a good outcome
compared to Angus Phillips' account in this issue of a different, very
expensive method of depowering the main (see "Lord Nelson Among the
Oystermen").

You'd think the best main-trim advice might
come from the most experienced sailor among our contributors, Webb
Chiles, who writes this month about a four-day trade-winds passage (see
"Open Hatches"). But Webb was a bit of a renegade on this trip and
didn't even bother to remove the mainsail cover. Then again, he never
had to worry about whether the mainsheet was cleated.