Subject: Re: Balancing the helm when reefing - Mast attitude
Here's how I understand these things.
1. A sailboat has a tendency to pivot around it's mast (and keel).
Therefore, if the foresail area is larger (and/or its thrust greater) than
the mainsail, the boat will have a tendency to want to pivot in the
direction of the foresail's thrust which is (except directly downwind) away
from the wind ("to the lee"), generating "lee helm." With a reefed main and
a full lapper, this is likely to occur assuming that both sails are shaped
for their maximum thrust or drive. If the mainsail is relatively
overpowered with regard to the foresail, the opposite will happen, and the
boat will want to pivot into the wind ("to the weather"), producing "weather
helm." Having to hold the tiller in any position other than exactly in the
center in order to maintain course is inefficient in that it increases drag.
Thus no "helm" at all is ideal although I prefer a little weather helm so
that I can head up as a default maneuver if I need to. BTW, this is why a
boat to leeward has right of way (so it can head up and stop for safety and
not be sailed into a disaster or an unwanted gybe by a boat to its windward
that wont give way).
2. To de-power the main, it is always helpful to flatten it. Thus, pulling
on the downhaul or Cunningham, on the outhaul, or tightening the backstay
will all de-power the mainsail allowing a more upright sailing attitude and
producing less weather helm (or more lee helm). Easing the mainsheet or the
traveler will add twist to the sail (as the boom rises - assuming the
Cunningham is also eased), spilling wind and further de-powering it.
This has made sense to me and seems to pan out in sail trimming. I also
agree that in a P-15 anyway (very very hard to tighten the backstay or do
much of anything with the Cunningham!), any kind of a chop can really make
your life miserable if you are trying to come about into the chop. That
high prow catches wind and water making any kind of low speed tack
impossible at times.
Scott Paist
P-15 TUMP
Lancaster, PA
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