"mr.b" wrote in message
m...
I'm consistently a kt. slower on the port tack than the starboard and
it's starting to make me nuts. Almost as nuts as the "weather" on the
Great Lakes this "summer".

To start, all the standing rigging is new as of last year with about 40
hours of total sailing time on it.

I measured the mast for plumbness using the main halyard, then tightened
the uppers by hand keeping the mast in column. Then snugged the forestay
hand tight. Then attempted to induce some prebend by tightening the aft
stay, first hand tight, then with a wrench. Sighting up the main track
shows a slight aft bend, maybe an inch over my 34' mast height, then
checking again for straightness athwartship. Finally hand tightened the
single inner shrouds.

Out for sail testing and on the starboard tack the boat falls into the
groove and runs right up to hull speed with a #3 and the full main in
about 12-15kts of breeze. Slight weather helm and I can trim her for
hands off at hull speed.

Tack to port and we have to fall to leeward a bit to get her to
accelerate and she never really gets into a comfortable groove. More
pronounced weather helm and she seems to be struggling to come to hull
speed.

On both tacks the inner shrouds flop loosely and I know that will need to
be dealt with next time out. As well, the forestay sags at least 5-6
inches from the centreline. I've read that "hand-tight" is good enough
for shrouds and stays but this can't be right. My pointing ability can't
be what it could be with such a loose rig.

I'm looking for tuning hints here. It's just a conventional masthead rig
with single lower shrouds and no backstay tensioner installed. Headsails
are hank-on. Main has 3 full battens.

Before you check for plumbness, start off by finding out if your chain
plates are in the same plane. On a calm day, prop a 2x4 or something across
the hull, position yourself right on the centerline and let the boat come to
rest, then level the 2x4. Finally measure down to the chain plates. If you
measure any difference, take that into account when you plumb the mast.

Checking for plumbness using the main halyard in pretty inaccurate. Get a
fifty-foot metal tape long enough to reach from the masthead to the
chainplates and plumb it that way.Start the upper shrouds at a fairly tight
hand tightness, check the plumbness, then adjust again by the same number of
turns of the turnbuckle looser on one side and tighter on the other. Then
snug up the lowers, maybe just a little bit looser than the uppers. Sight
the mast up the sail track for straight. This is your starting point. Now go
sailing in about ten or twelve knots of breeze, and flat water if you can
find it.

When you're close-hauled on starboard, sight up the sail track to see if the
masthead is sagging off to leeward, or if there's a bow either way. If the
masthead is sagging, luff up, tighten the upper a couple of turns, fall back
off, check it again until the mast is standing straight when close-hauled.
If it's bowing to leeward in the middle, tighten the lower on the weather
side to bring it back into column. Go about, run through the same steps on
the port tack. Then back to starboard, see if you've upset the tune on that
tack, fix it, then back to port and touch it up. By now you're setting the
rig up tight enough that you're feeling the burn in your hand when you make
an adjustment, and you might even be needing a wrench on the turnbuckles if
you're adjusting them under tension. By this time you're probably set up for
transverse trim. Once you're back in the slip, do the metal tape test for
plumbness again, and pull it back into plumb if necessary by loosening one
side by a counted number of turns and tightening the other by the same
number of turns.

While you're doing all this close-hauled sailing, get right down on the deck
and eyeball your weather chain plates and the deck as the boat works it way
along. Put your hand on it. Any flexing or movement in the deck or the
chainplate? See it on one side but not the other? If so, the load on the rig
might be distorting the hull, causing the rig to flex more to one side than
the other. In any case if you see something like that happening, stop
worrying about the rig tuning for a while and fix the structural problem,
then come back and try this again.

For fore-and-aft trim, sounds to me like you just need to take it up a notch
on tightness. In any case, a slack headstay would have the same effect on
both tacks and wouldn't cause the assymetrical performance problem you're
describing. You can go a lot tighter fore-and-aft than you're running it
right now. Six inches of sag on a rig that size sounds like a lot to me with
a #3 in that moderate breeze.

If transverse rig trim was causing your problem, the chances are good that
by the time you've gone through the process above the boat's sailing well on
both tacks. If not, something else is going on. It may sound obvious, but
check that the jib leads are set the same on both sides - same distance from
the bow, same distance off the center-line. Check the mainsheet system to
confirm that the boom is in the same orientation on both tacks - same
mainsheet tension on both sides, not a little closer to the centerline on
one tack than the other. Boom vang, if any, hauling the boom down harder on
one tack than the other? Lots of boats have somewhat assymetrical trimming
systems, because of mistakes in the way the gear leads.

Someone else has already mentioned that sometimes boat hulls aren't
symmetrical side-to-side. That's definitely true, and it could be that the
boat's airfoil shape is just better on one side than the other. Sometimes
it's the rudder that's shaped differently on one side than the other, giving
you the impression of more weather helm on one tack. For the hull shape,
it's kind of an involved process to discover if that's the problem, but it's
a bit easier for a keel, and quite a bit easier for a rudder. Reshaping the
rudder's not a big job, but refairing a keel is probably only worth it if
you're a racer.

Good luck,
Tom Dacon