HI Karen,
Boy, that's a lot of questions! I'll do my best to answer them all.
BTW, it would be helpful to list the year and hull number of your boat under
your name in your signature. Not all P19s are the same.
To determine the perpendicularity of the mast to the cockpit seats, I use a
level that can be used on both horizontal and vertical surfaces.
It would be hard to get reliable measurements if the boat is on the water,
because moving around on the deck will change the way a small boat like the
P19 floats on the water. You can do it with the boat on the trailer, by
adjusting the tongue height of the trailer until the seats are level fore
and aft (and make sure it's pretty level side to side too by parking on a
level surface, or else the weight of the mast leaning to one side may throw
the side tensions off).
A standard level will work just fine. Alternatively, I got a level at Sears
for about $10 that's a little right angle with a round bubble chamber that
has a rotating dial around it. You set it to zero on the seats, and then
read 90 degrees when you use it on the mast. It's only about 4" x 4", so it
fits in my tool bag better than a standard level.
As for the seats being sloped for drainage and the question if that affects
mast rake measurements, I don't know the answer. I use the seats as a
reference point for the initial dockside tune, and all I'm trying to do is
get the mast roughly pointing straight up somewhere between 0 and 3 degrees
of aft rake. I've never tried to get a lot of precison on the mast rake on
land, since you're going to adjust on the water to get the weatherhelm
correct anyway. The amount of weatherhelm is the most important determinant
you use to set mast rake.
Your next question - the slight backwards curve at the top of the mast:
It's not technically pre-bend -- we can it prebend when we tune it into the
rig. Pre-bend is usually a gentle curve (less than 2% chord) tuned in over
the whole length of the mast, which makes the column more stable. You
describe you mast as having a curve at the top (so the masthead is aft of
the rest of the column) when there's no real shroud tension.
Typically, masts that are tuned with pre-bend are straight when they're new,
but can get a little curve in "memory" over many years. From your
description, it sounds like your mast has a little memory at the very top,
not over the whole length. I don't what caused the curve at the top --
but, not to worry, that's not a bad thing, and may even give you a
performance advantage.
It may affect performance a teensy-weensy bit, but unless it's really
extreme, I doubt it you'll really notice it. A curve so the masthead is a
little aft of the rest of the column would give you a little less tension on
the leech of the mainsail, which allow the top of the sail to twist off to
leeward in the upper 1/3 of the sail. On most points of sail (close reach,
reach, and deep reach), you control leech tension (and thereby control
twist) with the vang. So, wiht your mast, you'll need to set the vang a
teensy bit little tighter than you might otherwise.
*********Warning: technical discussion of sail trim follows. Quit now if
that sort of stuff makes your eyes glaze over
You always want some twist in the upper sail compared to the lower part,
because the wind moves faster at the top of the mast than over the surface
of the water, which moves the apparent wind aft at the top of the mast
compared to the bottom. Every sail has some twist designed right into the
shape, and the basic amount of twist is adjusted with various controls to
suit various wind conditions. A good trimmer adjusts the sail to have the
right amount of twist for the wind conditions.
A good RULE OF THUMB for most sails and most boats is to have the second
batten approximately parallel to the boom. The top batten will be twisted
off more than the second batten, and the average sail will typically will be
fully powered up that way in moderate winds of 10-15 knots. But you may
decide to put more twist or less twist in the upper sail according to
conditons.
You'd want more than normal twist in two conditions:
1) in light air under 5-6 knots: in light conditions, when the wind is under
5 knots at the surface, it's moving probably blowing at least 5 knots faster
at the top of the sail. In those conditions, the power you get from the top
of the sail is greater than the power you get from the bottom of the sail,
even tho there's a lot more sail area at the bottom. So for pointing, you'd
want the angle of attack at the bottom of the sail to be much smaller than
at the top. In other words, you'd want a lot of twist to leeward in the top
to keep the top half of the sail powered up. So loosen the vang to get more
twist in the sail.
To get more twist in really light wind, you can use the topping lift to lift
the boom (be sure it's strong enough line), at least on one tack. On the
other tack it will be on the wrong side of the sail.
A boom kicker will also lift the boom if you don't tension the mainsheet too
hard. But make sure you release the topping lift before if the wind picks up
and you want to pull the boom to centerline.
Personally, I don't bother with the topping lift approach. It's too much
work for too little return. I just keep my vang pretty loose in light wind.
I sail slow when the winds are light. Or fire up my OB if I'm in a hurry.
(<gasp>. Judy B's not a purist :) If I had a traveller, though, I'd use
it.
2) Pointing and reaching in overpowering wind: When you're really close
hauled with the boom on the centerline, the mainsheet pulls the boom down
and acts like a vang. That puts tension on the leech of the main, reducing
twist. While close hauled in overpowered conditions, many boats are rigged
so you can reduce heeling (and therefore weatherhelm) by letting the top of
the sail twist off past it's fully powered-up position. It's like easing
the main when you're overpowered, but only at the top of the sail. If you
depower the top of the sail, you lower the center of effort from the main
and reduce heeling and weatherhelm. Conversly, if the leech has too little
twist, it's effectively oversheeted at the top, producing a lot of drag
compared to lift (which slows you down), and whatever power it is producing
is doing nothing more than heeling the boat excessively.
Without a traveller on the P19, it's danged near impossible to get extra
twist in the top of the sail while you're close hauled. If your masthead
fitting is storng enough (it is on the older P19's, but I'm not sure about
the newer ones), you can really crank on the adjustable backstay, and put
extra bend in the very top of the mast. So it may be an advantage to have
that "memorized" curve in the top of your mast, Karen. Other than bending
just the top of the mast, or using a traveller, the best option is to put a
reef in the main. Reefing the main is essentially the best course of action
on most P19s.
*********'End of technical sail trim discussion***************
Regarding your question about forestay tension. It's one I don't have a
good answer to. I'm going to ask my rigger about that one. Maybe he has a
pearl of wisdom. You can't get a Loos guage on it because of the extrusion,
so I've never been able to measure it. It should "feel" about as tight as
the upper side shrouds after your dockside tune. You'll get it set more
precisely after you sail the boat to set the mast rake for 3 degrees of
weather helm.
Regarding the furling line: Keep the thin line. You'll need it to get
enough line on the drum for your largest sail. If it's frayed, replace it
with similar line. Replace the chewed up plastic fairlead with a new one.
Maybe get one with a SS center That may get rid of some of the drag on the
line you're experiencing. Also be sure the front fairlead closest to the
furler is located so that the line feeds right at the center of the drum,
and is perpendicular to the axis of the drum. If it's not perpendicular, it
won't wrap around the drum evenly, it will build up on the top or bottom of
the drum and therefore bind. Also if the furling line leads in from too
high, it will tend to cause the CDI to "float" up the forestay, exposing the
innards of the furling mechanism and chafing the line.
I have the front fairlead mounted on the stanchion, but there are lots of
places to put it so it will work right. Just make sure the furling line is
perpendicular to the middle of the drum as it leaves the block or fairlead.
It does take a modest exersion to furl the sail -- you should maintain a
light tension on the jib sheets as you haul on the furling line so you get a
tight wrap around the extrusion. You can do it on any point of sail and I
have. But in high winds, it's easier if you point just a little too high,
so the jib still has wind in it but is on the verge of stalling out.
All you need to do for maintenance on most CDI's (most of them have that
simple single white plstic bearing inside and don't have or need the
optional $75 ball bearings) is rinse to it out with water occassionally,
especially if you've just trailered the boat thru a dust storm or it's been
sitting outside all winter.
If the grey plastice extrusion (the long piece with the groove) has gotten a
memory from being left in the sun, you can straighten it out by leaving it
straight in a warm place The owner's manual says it'll be okay if it's
curved during storage, up to about 140 degrees. If yours was left kinked in
over 140 degrees, we can only hope for the best. You can find more info at
http://www.sailcdi.com/ffmain.htm , which is the website for CDI. They'll
send you a manual if you request it.
Hope all this helps.
Judy B
1985 WWP19 #266 Redwing
SF Bay, CA
-----Original Message-----
From: Karen Johnson [mailto:kojohns@ix.netcom.com]
Sent: Monday, May 08, 2000 1:30 PM
To: WWPotter@egroups.com
Subject: [WWP] Re:P-19 Forestay Adjustment/Rigging
Thank you Judy B. for your instructions on Rigging a P-19. We recently
adopted "Miss Maggie," a P-19 from Clemson, SC. (We live near Cleveland,
OH). We weren't sure how to rig her, but your post from a week ago
sure helped. However, we do not seem to have the sensitivity to visually
determine if the mast is perpendicular to the cockpit seats. We tried to do
this at the dock at a ramp, but it was too busy and then we
anchored and did the rigging there. We couldn't see what we were doing. I
am wondering if we can rig her in the driveway by putting a level on a
cockpit seat and adjusting the trailer wheel jack until the seats
are level. Then tying a weight on the halyard and using it as a plumb line
to get the mast perpendicular to the seats. Should this work? Have you
ever tried anything similar? I am concerned that the seats are
on a slight angle for drainage.
As a note, the mast itself seems to have a slight backwards bend towards
the top without the rigging causing it. Is that possibly pre-bend?
Also, after we tightened the the shrouds(the lowers at a low pitched
musical note and the uppers are on a bit higher note), we then tightened the
forestay. We had a hard time determining how tight to make it
since we have a genoa rolled on it. We did notice that
when we took it off after our sail, we might not have been able to put it
back on since we could only pull it by hand to within an inch or so of the
chainplate, which sounds like we had it too tight. The
turnbuckle was almost all of the way shortened, also. How do we gauge the
proper tension on the forestay with roller furling? Can we use one of those
Johnson quick release levers on the forestay in addition to
the backstay when we have roller furling?
Also, we are having some problems with the roller furling. The line
seems too small and it seems way too hard to pull on to furl. We took it
apart and didn't find any problems. However, the gray plastic
outside of the furler where the sail slides into has a fairly big kink in it
like it was left in the sun and it semi-melted while hanging over the edge
of something. I don't know if that is a problem. With the
forestay tight, the kink smooths out. Also, the fairlead that the reefing
line goes through after it comes off the roller furler has a large groove
chewed through it and it is chewing up the line. Can the reefing
line be replaced by maybe a 1/4" line? Do you have a fairlead on your boat
or a block(pulley) instead?
Thanks so much to all of you. We are learning a lot by reading your
messages.
Happy Pottering,
Karen Johnson
"Miss Maggie," P-19
Grafton, OH
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