mr.b wrote:
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.

It could be a tuning issue, though next time you haul the boat you might
want to check to be sure the keel is properly aligned.

--Alan

"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

Probably not a rig tuning issue but rather a hydrodynamic anomaly with
your paddlewheel.

If the paddlewheel is mounted off of the boat's centerline it will
rotate differently on on tack than the other and 1. differing depths
(on one tack the paddlewheel is deeper than on the opposite tack. 2.
the amount of leeways 'slip' the boat is experiencing versus #1
above.

Unless the paddlewheel is accurately mounted ON the boats centerline
it will virtually ALWAYS read differently when SAILING on different
tacks. Its a problem of hydrodynamics versus different 'flow
regimes'.

On Sun, 26 Jul 2009 11:58:01 -0700, RichH wrote:

Probably not a rig tuning issue but rather a hydrodynamic anomaly with
your paddlewheel.

If the paddlewheel is mounted off of the boat's centerline it will
rotate differently on on tack than the other and 1. differing depths (on
one tack the paddlewheel is deeper than on the opposite tack. 2. the
amount of leeways 'slip' the boat is experiencing versus #1 above.

Unless the paddlewheel is accurately mounted ON the boats centerline it
will virtually ALWAYS read differently when SAILING on different tacks.
Its a problem of hydrodynamics versus different 'flow regimes'.

Thanks Rich,
I'm happy to have had so many quality responses to this thread. Lots of
informed opinion and much to think about.
In fact the paddlewheel is mounted off-centre to port by about 10 inches
or so. I'll be back up to the old girl in a day or two and the bug-
hunting is going to start with verifying your proposition. I know I do
have some looseness in the rig that must be dealt with but nonetheless,
your suggestion seems to satisfy Ockham's razor.
We'll see.
Cheers

On Jul 26, 4:19*pm, "mr.b" wrote:
On Sun, 26 Jul 2009 11:58:01 -0700, RichH wrote:
Probably not a rig tuning issue but rather a hydrodynamic anomaly with
your paddlewheel.

If the paddlewheel is mounted off of the boat's centerline it will
rotate differently on on tack than the other and 1. differing depths (on
one tack the paddlewheel is deeper than on the opposite tack. 2. the
amount of leeways 'slip' the boat is experiencing versus #1 above.

Unless the paddlewheel is accurately mounted ON the boats centerline it
will virtually ALWAYS read differently when SAILING on different tacks.
Its a problem of hydrodynamics versus different 'flow regimes'.

Thanks Rich,
I'm happy to have had so many quality responses to this thread. *Lots of
informed opinion and much to think about. *
In fact the paddlewheel is mounted off-centre to port by about 10 inches
or so. *I'll be back up to the old girl in a day or two and the bug-
hunting is going to start with verifying your proposition. *I know I do
have some looseness in the rig that must be dealt with but nonetheless,
your suggestion seems to satisfy Ockham's razor.
We'll see.
Cheers

Easy to test out/verify .... MOTOR first on several tacks (on
equivalent magnetic course that would equate to 'beating' with sails
up but luffing and record speed versus; then, stop the engine and SAIL
the tacks and record the speed / angle of heel, etc. The difference
between the 4 sets of numbers will be your 'correction factor' for
that speed versus apparent wind angle versus heel angle. You can
build a full set of corrections for later usage if you want ... but
best is to mount the paddlewheel ON the centerline to avoid
hydrodynamic anomalies.
BTW - 'most' instruments are NEVER direct read devices but usually
need some 'correction factor' applied - pressure, temperature, speed,
etc. etc. etc. etc. etc. its just the 'way of instrument usage in a
technical world'.

"RichH" wrote in message
...
On Jul 26, 4:19 pm, "mr.b" wrote:
On Sun, 26 Jul 2009 11:58:01 -0700, RichH wrote:
Probably not a rig tuning issue but rather a hydrodynamic anomaly with
your paddlewheel.

If the paddlewheel is mounted off of the boat's centerline it will
rotate differently on on tack than the other and 1. differing depths (on
one tack the paddlewheel is deeper than on the opposite tack. 2. the
amount of leeways 'slip' the boat is experiencing versus #1 above.

Unless the paddlewheel is accurately mounted ON the boats centerline it
will virtually ALWAYS read differently when SAILING on different tacks.
Its a problem of hydrodynamics versus different 'flow regimes'.

Thanks Rich,
I'm happy to have had so many quality responses to this thread. Lots of
informed opinion and much to think about.
In fact the paddlewheel is mounted off-centre to port by about 10 inches
or so. I'll be back up to the old girl in a day or two and the bug-
hunting is going to start with verifying your proposition. I know I do
have some looseness in the rig that must be dealt with but nonetheless,
your suggestion seems to satisfy Ockham's razor.
We'll see.
Cheers

Easy to test out/verify .... MOTOR first on several tacks (on
equivalent magnetic course that would equate to 'beating' with sails
up but luffing and record speed versus; then, stop the engine and SAIL
the tacks and record the speed / angle of heel, etc. The difference
between the 4 sets of numbers will be your 'correction factor' for
that speed versus apparent wind angle versus heel angle. You can
build a full set of corrections for later usage if you want ... but
best is to mount the paddlewheel ON the centerline to avoid
hydrodynamic anomalies.
BTW - 'most' instruments are NEVER direct read devices but usually
need some 'correction factor' applied - pressure, temperature, speed,
etc. etc. etc. etc. etc. its just the 'way of instrument usage in a
technical world'.

I know of no production boats with the paddle wheel on the centerline.
Regards,
JR

On Tue, 28 Jul 2009 08:48:46 -0400, "JR" wrote:

I know of no production boats with the paddle wheel on the centerline.
Regards,
JR

It is usually impractical unless you are willing to live with a
transducer in the middle of your forward cabin sole. In addition to
being exactly on the centerline and precisely aligned, it is also
necessary to be at least a foot or two forward of the keel. We
decided that port and starboard transducers were the best of the bad
choices available. That has its own issues however, not the least of
which is switching on every tack or jibe. It would also be highly
desirable to have separate calibration controls for each transducer
but that is even more difficult in most cases.

"JR" wrote in message
...
I know of no production boats with the paddle wheel on the centerline.
Regards,
JR




I have one...

Mounted on the keel line near the bow, along with a depth and temp sounder
it does very nicely. Transducer and senders connect to the fish finder
which, unlike my other two depth gauges, allow positive as well as negative
offset, so that's the "true" depth meter, where the others are "under-keel"
meters...

Go to the bow, drill the appropriate hole, apply the appropriate fairing,
and now you have a centerline mounted instrument :{))

L8R

Skip, still working on the boat but having the end in sight. Painting the
last parts starts tomorrow...

--
Morgan 461 #2
SV Flying Pig KI4MPC
See our galleries at www.justpickone.org/skip/gallery !
Follow us at http://groups.yahoo.com/group/TheFlyingPigLog
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"You are never given a wish without also being given the power to
make it come true. You may have to work for it however."
(and)
"There is no such thing as a problem without a gift for you in
its hand
(Richard Bach)

Putting the paddlewheel on the centerline will also generate some
potential problems ..... it has to be mounted so that it cant be
destroyed by the sling of a travellift when the boat is hauled ... not
an easy thing to do.

On Tue, 28 Jul 2009 10:34:52 -0700 (PDT), RichH
wrote:

Putting the paddlewheel on the centerline will also generate some
potential problems ..... it has to be mounted so that it cant be
destroyed by the sling of a travellift when the boat is hauled ... not
an easy thing to do.

The easiest way to manage that is to pull the paddle wheel and insert
the dummy plug before haul out. If you are really religious about
your instrument calibration it is best to pull the paddle wheels every
time you come back in from sailing. It helps to prevent growth or
slime from forming and throwing off the speed readings. When you are
trying to accurately compute true wind direction and speed it doesn't
take much knot meter error to throw the whole calculation out of
kilter.