OK, I’m finally getting far enough ahead of the curve on the basics
that I can start thinking about sail shape. I can see from the replies
to my post on the backstay that I’ve forgotten a lot over 20 years of
not sailing much except in gaffers.

We have an impressive amount of main backwinding despite a wide
headsail sheeting base on our boat. I haven’t been able to fiddle and
experiment much because we are still spending a lot of time short
tacking in confined waters with a lot of traffic and it’s hard to play
with sail controls when new helmskids are wandering all over the
place.

Our boat seems to go well with the 140 genoa just touching the
spreader tips and the foot along the lifelines. Is this too tight to
expect a smooth main? By the time the wind is strong enough that I
need to ease her in the puffs, the main is often completely depowered
and flogging, even with the traveler nearly amidships.

Is this the proper prescription for backwinding?

More stay and jib luff tension.

Genoa sheet leads farther aft to ease leech.

Main Cunningham (just added but not used yet)

Maximum vang tension to detwist main.

I’ve done some Googeling for "sail trim" but it sounds like there’s
much to be learned here.

BTW our E32 has a modified rudder so I don't know how the stock boats
behave but the handling of ours is superb. I've driven her down hard
and there is never a hint of the sails taking charge. She is a
delight to steer even when way overpowered.


--

Roger Long

Roger,

[I'm about to expose my ignorance... not letting that stop me!] I've been
sail-racing once a week (for 4 or 5 months a year) for about five years, so
still have much to learn. Others will improve on these preliminary thoughts.

1/ Don't let the sail touch the spreaders even when as close-hauled as
possible.

2/ Under maximum close-hauling in heavy winds, a little backwinding of the
main just along the luff isn't the end of the world. That's not where most
of the propulsion comes from, and other factors may be optimized enough to
counter that "undesirable" one.

3/ A 140 genoa is a big sail for lots of short tacks. It may theoretically
be the "right" sail in light winds, but smaller sails are easier to manage.
How much crew do you carry?

4/ Along those lines, you mention "over-powering." Not the most efficient
(or safe) way to sail a boat.

5/ When you let go the tiller or steering wheel, it is normal for the boat
to round up to wind - and much safer than the converse! Having to hold a
little "weather helm" does add some drag, but I think is considered normal
performance and a good safety design feature.

6/ I'm not sure I understand your further statements (or questions?) about
sail trim, but you're right, it's a big topic. The very general approach is:
everything tighter in heavier winds, looser in lighter, and yet looser in
bigger waves. Then you get into the differences between full and fractional
rigs... :-)

Then, I was sailing with my father-in-law and asked whether I should make
some small adjustment to the jib sheet. He sounded surprised, and said "But,
we're moving..." (He's a cruising - not racing - boater...)

Charles

====

Charles T. Low
www.boatdocking.com

====

"Roger Long" wrote in message
news
OK, I’m finally getting far enough ahead of the curve on the basics that I
can start thinking about sail shape. I can see from the replies to my post
on the backstay that I’ve forgotten a lot over 20 years of not sailing
much except in gaffers.

We have an impressive amount of main backwinding despite a wide headsail
sheeting base on our boat. I haven’t been able to fiddle and experiment
much because we are still spending a lot of time short tacking in confined
waters with a lot of traffic and it’s hard to play with sail controls when
new helmskids are wandering all over the place.

Our boat seems to go well with the 140 genoa just touching the spreader
tips and the foot along the lifelines. Is this too tight to expect a
smooth main? By the time the wind is strong enough that I need to ease
her in the puffs, the main is often completely depowered and flogging,
even with the traveler nearly amidships.

Is this the proper prescription for backwinding?

More stay and jib luff tension.

Genoa sheet leads farther aft to ease leech.

Main Cunningham (just added but not used yet)

Maximum vang tension to detwist main.

I’ve done some Googeling for "sail trim" but it sounds like there’s much
to be learned here.

BTW our E32 has a modified rudder so I don't know how the stock boats
behave but the handling of ours is superb. I've driven her down hard and
there is never a hint of the sails taking charge. She is a delight to
steer even when way overpowered.


--

Roger Long

I pretty much agree. Ease the genny a bit and flatten the main -- lots
of vang, main halyard and/or cunningham, outhaul, backstay if your mast
bends, babystay if you have one, running backs (if any) just enough to
prevent mast pumping, and traveler relativly high.

Don't worry about "speed bubbles" as long as the leech of the main is
working. You don't want the whole sail to flog, though.

You can also de-power the genny. If you have moveable jib cars (can you
tell I race?) move them back. The top of the jib will twist off and
make things more comfortable.

North Sails has North U. which has classes on sail trim, racing tactics,
etc. They also sell their books. You may want to look at Performance
Racing Trim at
http://www.northu.com/nu/NU_catalog....ory=21&flash=5

If you have purchased a sail for your boat, badger the sailmaker for
tuning guides.

Good Luck!

tom
of the Swee****er Sea

Roger

Like the other posters said, a little back winding is nor porblem.

On masthead boats, we susally sheet the genoa in until it just about
touches the spreaders. Do you have a traveller for the main? If yes,
use it to position the boom at, or close to the center line of the boat
but don;t forget to make sure you've not stalled the sail. A couple of
tell telas at the leech will really help here.

If you don't have a traveller, adjust the sail for th ecorrect shape,
ignore the remaining back winding and have another beverage

Cheers

Matt

"backwinding" is quite an incorrect term as whats happening ISNT coming
from the genoa.

Whats happening is either that the leech shape of the genoa is too
straight and or the genoa has too great a LP to match with the
Mainsail. If the mainsail has correct shape (by design and set) then
the remedy is to cut away some of the leech in the middle to affect a
greater 'hollow' of the leech. Try easing the genoa sheet to increase
the distance and see what happens.
Of course if the position of draft on the mainsail is too far forward
(too much halyard tension) then you will get the same result.
"backwinding' for pointing/beating will have virtuallly NO adverse
effect on sailing performance (If the genoa is trimmed correctly).

Most commonly, especially with an older mainsail, is there is an
'ageing' change to the luff dimensions caused by a shinking/shrunken
bolt rope.
A mainsail with a shrunken boat rope will have the following
characteristics: VERY full shape, hooked to windward leech, great
amount of draft that cant be minimized by gross outhaul tension - sail
cant be 'flattened' by extreme halyard and outhaul tension - boat will
heel very easily and the boat speed is usually very Blah! -- the boat
will have more than necessary weather helm (unless you use bar-tight
halyard pressure).
A mainsail 'should' have a somewhat FLAT shape at the luff (entry) and
maximum draft at about 40% to 50% cord length back from the mast. A
sail with a shrunken boltrope will have a 'bulging draft right behind
the mast .... and if you overtighten the halyard (to adjust helm
pressure) the bulge will get even larger (.... and cause what looks
like 'backwinding').

If you have the original dimensions of the sail simply use a steel tape
measure and verify. If you have any PHRF or other racing 'black
bands' embossed on the mast raise the sail with extreme halyard
pressure and see if the sail fits exactly between the bands .... if the
sail luff length comes up short - then the boltrope is shrunken and
needs to be 'eased'.
Boltropes are purposely made shorter (1" shortening for every 10 ft. of
luff length) than the original luff dimensions so that the sail will
keep shape at the higher windranges (15-18kts.) when you put "proper'
halyard tension to it. These ropes are usually three strand dacron.
Every time you stress these ropes they become fatter and shorter until
eventually the sail shape is abysmal. A sailmaker can easily 'ease'
such a shrunken bolt rope (so can you if you have waxed sailtwone and
sailmakers hand needles, etc.) --- but will want to sell you a new sail
first. On dacron sails I usually need to adjust/ease the boltropes
after just about every (hard) sailing season.

;-)




In article , Roger Long
wrote:

OK, I’m finally getting far enough ahead of the curve on the basics
that I can start thinking about sail shape. I can see from the replies
to my post on the backstay that I’ve forgotten a lot over 20 years of
not sailing much except in gaffers.

We have an impressive amount of main backwinding despite a wide
headsail sheeting base on our boat. I haven’t been able to fiddle and
experiment much because we are still spending a lot of time short
tacking in confined waters with a lot of traffic and it’s hard to play
with sail controls when new helmskids are wandering all over the
place.

Our boat seems to go well with the 140 genoa just touching the
spreader tips and the foot along the lifelines. Is this too tight to
expect a smooth main? By the time the wind is strong enough that I
need to ease her in the puffs, the main is often completely depowered
and flogging, even with the traveler nearly amidships.

Is this the proper prescription for backwinding?

More stay and jib luff tension.

Genoa sheet leads farther aft to ease leech.

Main Cunningham (just added but not used yet)

Maximum vang tension to detwist main.

I’ve done some Googeling for "sail trim" but it sounds like there’s
much to be learned here.

BTW our E32 has a modified rudder so I don't know how the stock boats
behave but the handling of ours is superb. I've driven her down hard
and there is never a hint of the sails taking charge. She is a
delight to steer even when way overpowered.

"On masthead boats, we susally sheet the genoa in until it just about
touches the spreaders."
Thats strange, I usually barber-haul most mastheaded boats or run a
second set of sheets INSIDE the rail to affect better pointing/speed
..... and usually place somewhere at the front of the fleet.

He's probably got a mainsail thats out of shape.

For tell-tales, etc. go to www.arvelgentry.com and read the 'magazine
articles' (archives from the 1970s) .... if you want to sail on the
'edge'.




In article .com, wrote:

Roger

Like the other posters said, a little back winding is nor porblem.

On masthead boats, we susally sheet the genoa in until it just about
touches the spreaders. Do you have a traveller for the main? If yes,
use it to position the boom at, or close to the center line of the boat
but don;t forget to make sure you've not stalled the sail. A couple of
tell telas at the leech will really help here.

If you don't have a traveller, adjust the sail for th ecorrect shape,
ignore the remaining back winding and have another beverage

Cheers

Matt

Rich Hampel wrote:
"On masthead boats, we susally sheet the genoa in until it just about

touches the spreaders."

Thats strange, I usually barber-haul most mastheaded boats or run a
second set of sheets INSIDE the rail to affect better pointing/speed
.... and usually place somewhere at the front of the fleet.

He's probably got a mainsail thats out of shape.

Naw, he's got the genny brakes on. A bag, a hook, too close in, too
slow, too low. Sometimes a smaller flatter inboard jib is just
plain faster to windward, as well as being far more comfortable. A
genny is a light air sail, not a moderate air sail.

Luffing, or a bubbly main luff, wants more outhaul, gooseneck down,
cunningham on, mainsheet in. If it softens occasionally, it is set
right. Everything is so relative. A study of butterfly flight
revealed their vortex generators generated low drag leading edge
turbulence, loosely coupled to the wings, which were very similar in
performance to a more shapely, heavier leading edge.

Keeping the boat upright means the keel doesn't slip so much. Once
it starts to carve, you don't need a lot of sail, or for that
matter, a lot of keel. Canted keels help.

A genny is an off the wind sail, unless it is able to go spanking
flat, close in to windward. It's silly to expect a light sail not
to stretch when abused. Sails should be cared for, as expensive
fuel costs. Decent sails, used decently can go ten years. Used by a
fool, the best can be ruined in one race, one gust.

Of course, I've never flown a new, super tech material sail.

That's one reason why we call cruising sailing nowhere special, at
economical speed. (Pocket Oxford) The economy of effort is also a
factor. A self tending jib is what makes a cruiser. Racing, or
aspiring to seem to be a racing type, is a different matter.

Excuse me, while I aspire to snobbery.

Agressive humility? Sure, why not? I got a lot to be humble about.


For tell-tales, etc. go to www.arvelgentry.com and read the 'magazine
articles' (archives from the 1970s) .... if you want to sail on the
'edge'.

In article .com, wrote:


Roger

Like the other posters said, a little back winding is nor porblem.

On masthead boats, we susally sheet the genoa in until it just about
touches the spreaders.

This is to avoid wearing a hole in the sail, it says nothing about
sail trim, except that you cannot sheet a large sail where you
might, were performance the only goal. -tk

Do you have a traveller for the main? If yes,
use it to position the boom at, or close to the center line of the boat
but don;t forget to make sure you've not stalled the sail.

This may be true, but for only one condition. If you are going to
windward and feel you should centre the boom, then you must have
some twist in it if it is to do any good at all, and the foot must
be stalled. If you need twist to depower the sail, you should be
seriously considering reefing something. Enough is enough, too much
excess power being used to balance too much excess power is not the
most economical approach to sail burn ratios. Let's hope it won't
shorten the life of steel wire and fiberglass, let alone aluminium
extrusions, stressed out crew, spilly bartenders, harrassed helmsmen
and navigator-tacticians. This is not cruising.

Terry K

A couple of
tell telas at the leech will really help here.

If you don't have a traveller, adjust the sail for th ecorrect shape,
ignore the remaining back winding and have another beverage

Cheers

Matt

Terry Spragg wrote:
Sails should be cared for, as expensive fuel costs.
Decent sails, used decently can go ten years. Used by a fool, the best
can be ruined in one race, one gust.

I'm quite happy to see how well my good old boat performs against some
of the larger, newer boats using mylar etc. A previous owner bagged out
the original Charlie Smith mainsail but I still use the original fairly
heavy weight 1966 Charlie Smith dacron working jib and along with a
repro dacron main, my little 28 footer will do over 8kts in 15-20kts of
breeze. Put a reef in at 25kts and she'll flirt with 10 kts.

Of course, I've never flown a new, super tech material sail.

I have been toying with the idea of a fully-battened main but dacron
still, but I'm not quite sure what more I'd get out of it but I am sure
I don't need mylar.

In article ,
prodigal1 wrote:
Terry Spragg wrote:
Sails should be cared for, as expensive fuel costs.
Decent sails, used decently can go ten years. Used by a fool, the best
can be ruined in one race, one gust.

I'm quite happy to see how well my good old boat performs against some
of the larger, newer boats using mylar etc. A previous owner bagged out
the original Charlie Smith mainsail but I still use the original fairly
heavy weight 1966 Charlie Smith dacron working jib and along with a
repro dacron main, my little 28 footer will do over 8kts in 15-20kts of
breeze. Put a reef in at 25kts and she'll flirt with 10 kts.

Ummm... isn't the hull speed 1.34x(sq.root of waterline)? So that
would be about 7 kts. Are you surfing or own a multi?

How did you arrive at the 8-10 kts?

--
Jonathan Ganz (j gan z @ $ail no w.c=o=m)
http://www.sailnow.com
"If there's no wind, row."

Lots of food for thought here. I find the idea of ruining the shape
of my genny in one day troubling. It's a roller furling sail with
foam leading edge and weather cloth leach. It feels to be about as
heavy as the main so I think it's a cruising sail intended to take a
good deal of abuse.

I don't actually carry it touching the spreaders. That's where I
crank it to while headed up a bit to ease the grinding. By the time
full power is developed, it's a good six inches off the spreaders. (I
need new sheets next year.)

I'm not a hard driver either, you get to windward a lot faster
identifying the optimum heel angle and then just steering to maintain
that when the boat is overpowered and you can't make a sail reduction.
I have intentionally driven the boat down to learn how she will handle
in sudden or unexpected gusts but I don't make a practice of it.

This is certainly not the rig I would have chosen but it came with the
hull and interior I wanted. I hope to rework it someday. Maybe I've
got too much time in more traditional boats but I'm amazed how fast
this shoal draft boat with its not-too-efficient keel goes and points.

The boat is a joy with the working jib. I'd probably sail with it a
lot if it were not for the hassle of making changes with the roller
furling. Leaving it up without the weather cloths on the leach would
shorten its life more than I want. One of the first items on my
Christmas list is one of those hoisting covers so I can leave the
smaller sail up during periods I expect brisk winds. Second is an
asymmetrical spinnaker so I don't need the area of the genoa off the
wind.

If someone came along and offered to trade my roller furling rig for a
set of hank sails, I would seriously consider it now that I've sailed
with the roller for a few weeks.

--

Roger Long



"Terry Spragg" wrote in message
...
Rich Hampel wrote:
"On masthead boats, we susally sheet the genoa in until it just
about

touches the spreaders."

Thats strange, I usually barber-haul most mastheaded boats or run a
second set of sheets INSIDE the rail to affect better
pointing/speed
.... and usually place somewhere at the front of the fleet. He's
probably got a mainsail thats out of shape.

Naw, he's got the genny brakes on. A bag, a hook, too close in, too
slow, too low. Sometimes a smaller flatter inboard jib is just
plain faster to windward, as well as being far more comfortable. A
genny is a light air sail, not a moderate air sail.

Luffing, or a bubbly main luff, wants more outhaul, gooseneck down,
cunningham on, mainsheet in. If it softens occasionally, it is set
right. Everything is so relative. A study of butterfly flight
revealed their vortex generators generated low drag leading edge
turbulence, loosely coupled to the wings, which were very similar in
performance to a more shapely, heavier leading edge.

Keeping the boat upright means the keel doesn't slip so much. Once
it starts to carve, you don't need a lot of sail, or for that
matter, a lot of keel. Canted keels help.

A genny is an off the wind sail, unless it is able to go spanking
flat, close in to windward. It's silly to expect a light sail not
to stretch when abused. Sails should be cared for, as expensive
fuel costs. Decent sails, used decently can go ten years. Used by a
fool, the best can be ruined in one race, one gust.

Of course, I've never flown a new, super tech material sail.

That's one reason why we call cruising sailing nowhere special, at
economical speed. (Pocket Oxford) The economy of effort is also a
factor. A self tending jib is what makes a cruiser. Racing, or
aspiring to seem to be a racing type, is a different matter.

Excuse me, while I aspire to snobbery.

Agressive humility? Sure, why not? I got a lot to be humble about.


For tell-tales, etc. go to www.arvelgentry.com and read the
'magazine
articles' (archives from the 1970s) .... if you want to sail on the
'edge'.
In article .com,
wrote:


Roger

Like the other posters said, a little back winding is nor porblem.

On masthead boats, we susally sheet the genoa in until it just
about
touches the spreaders.

This is to avoid wearing a hole in the sail, it says nothing about
sail trim, except that you cannot sheet a large sail where you
might, were performance the only goal. -tk

Do you have a traveller for the main? If yes,
use it to position the boom at, or close to the center line of the
boat
but don;t forget to make sure you've not stalled the sail.

This may be true, but for only one condition. If you are going to
windward and feel you should centre the boom, then you must have
some twist in it if it is to do any good at all, and the foot must
be stalled. If you need twist to depower the sail, you should be
seriously considering reefing something. Enough is enough, too much
excess power being used to balance too much excess power is not the
most economical approach to sail burn ratios. Let's hope it won't
shorten the life of steel wire and fiberglass, let alone aluminium
extrusions, stressed out crew, spilly bartenders, harrassed helmsmen
and navigator-tacticians. This is not cruising.

Terry K

A couple of
tell telas at the leech will really help here.

If you don't have a traveller, adjust the sail for th ecorrect
shape,
ignore the remaining back winding and have another beverage

Cheers

Matt