Conference unifix::sailing

I would be unwilling to bend the mast past the point where the front of
the masthead is aft of the aft side of the mast at the spreaders. Might
be better to have the main recut flatter.

I just received this months copy of Better Boat (a newsletter
published by the Practical Sailor people) that has a detailed 
description of the tuning of the mast.

The article is lengthy, so I won't try to type it in here, but
if anyone is interested in hardcopy just send me a message on
ENET.

The concept of hooking the mast follows four basic steps;
1.  Set athwartship vertcal by adjusting upper shrouds.  A good
    check is to use the Jib halyard from gunwhale on one side to
    the other side.
2.  Set Fore and Aft mast rake with Forestay and Backstay.  Adjust
    according to designers plans or to compensate for helm balance.
3.  Using the main halyard as gauge pull mast forward with lower
    forward shrouds to create 1-2" hook.
4.  Tighten backstay to increase bend to 1/2 to full fore and aft
    diameter of the mast.

The reason for Pre-bending the mast is to eliminate the tendancy
of the mast to pull back under full sail load.  Most sails are
cut with this in mind.  As the sail ages it will stretch along the
luff requiring more of a bend in the mast to flatten the sail.

ASK AND THOU SHALT RECEIVE!

It seems that every magazinr I pick up has an article on
tuning the mast.  This months Cruising World has one also.

It basically says that you should put enough bend in the mast
to flatten the main.  This is exactly what I was looking for.

Jeff

    Is there a differece is tuning rod rigging over cable ?
    

    Rigging and more rigging
    
    there are all kinds of tricks to tuning the mast.....one thing I
    found with my boat is that I had to adjust the mast rigging enough
    to change recommended specs. This was so I could handle the tiller
    more easily in a stiff wind. I also changed my spreaders from aluminum
    to stainless steel. (I had to make my own)

    I found a similar problem with my furling headsail, the method I used
    was to wrap some cloth around a short length of rope, saturate the
    cloth in silicone wax (car polish) and haul it up the track. 
    
    I'm not sure it improved anything but it made me feel better!!!
    
    
    P.S. don't forget to add a down haul or you'll need long arms.
    
    
    	Regards
    
    			Gregg

  I have a Bill Stevens designed O'Day 22.  It tacks very poorly.  I don't know
if the problem is hull design, bad sails, or what...?

  The hull has a very flat bottom and shallow draft (23").  The relatively high
bow tends to catch the wind.  The main sail has a bad wrinkle.  The original
sails where lost in a fire and replaced with some old O'Day sails.  A
sailmaker speculated that the main was from a racing model O'Day with a raked
mast.  I know I loose a lot of power from the poor shape of this main.

  The boat will not tack at all with just the main, too much windage on the
bow.  With my 110% jib up, I can close haul to about 45 degrees, but in light
winds I must bear off to build up enough speed to tack.  In tacking, I must
swing through about 130 degrees to build up speed, then I can bear up to a
close haul again.  In very light winds I have to wear (tack by jibbing). 
If I try to tack through a light wind I just don't make it.  I don't get caught
in irons, I just fall off with the wind as the boat looses momentum.

  I've tried moving weight around in my boat to change the center of balance,
but it doesn't seem to make any difference.  The boat definitely has lee helm,
with my hand off the tiller, it will bear off and run away from the wind.

  I'm trying to decide whether some changes (new sails, more keel, etc.) would
make a difference, or whether the poor performance is an innate part of the
boat's design.  I'd love to hear from others who have successfully improved
their boat's tacking performance.  Perhaps some other O'Day owners can tell
me how their boats perform.

    Try lengthening the forestay and tightening the backstay in 1"
    increments to rake the mast back.  At some point this should reduce the
    lee helm problem although in light air, most boats have some lee helm. 
    It should not, however, be so great that tacking is impossible.
    
    Another cheap thing to do is to make sure the main is sheeted in
    sufficiently tightly.  Trim the main until the top batten is parallel
    to the boom when sighting up the boom towards the masthead.  If the top
    batten cannot achieve this position, the leech may have stretched so
    that the mainsheet tension is borne by the portion of the sail at the
    inboard end of the batten pockets.  A leech that falls off to leeward
    no matter what the mainsheet tension is a sure sign of this.  In effect
    the useful sail area is reduced to that amount below the battens.  The
    cure is recutting the leech.
    
    If the leech hooks to weather, the problem is elsewhere.  A bubble just
    aft of the mast can sometimes be cured with additional outhaul tension. 
    Also, as you rake the mast back, it will want to bend slightly as the
    mainsheet is tightened.  This will tend to reduce the luff bubble.  If
    not, recutting the luff may be needed.
    
    Tension on the shrouds may have an impact.  Uppers should be tight,
    lowers loose.  When close hauled, sight up the mast.  In light air
    there should be slight leeward sag in the middle with the tip arcing
    slightly to weather.  If not, tighten uppers and loosen lowers until it
    happens.
    
    In light air putting body weight to leeward gives the curvature of the
    hull a chance to induce some weather helm.  Maybe not enough to
    completly offset the lee helm but it should help.
    
    Some boats with high aspect mains (foot < 30% luff) just don't sail
    well with just the main but even those should get enough drive out of
    it to point the bow into the wind.
    
    - gene
    
    

    I have a new O'Day Daysailer 3.  After a summer of weekending, I notice
    the shrouds are looser than they were on day#1.  I expect that since
    wire does stretch.  I understand that the tension needs to be the same
    on each, but I don't know how much tension that should be. 
    
    How much tension, how do I measure it, and how sensitive are the
    aluminum spreaders to too much tension?
    
    Dave

If you're not racing, don't worry about the tension, as long as you don't
make it too tight. A good rule of thumb is to have the lee shrouds just barely
slack when you're on a close reach in a moderate to strong breeze.

More important is to make sure your mast is vertical. To check this, use the
main halyard to measure to the same place on each side of the boat, e.g. to
the chainplate. If the main halyard is same length to both sides, then your
mast is vertical, i.e. perpendicular to the beam of the boat.

If your boat has both lowers and uppers, sight straight up the mast (look
up, with your head near the mast) to check for any bow induced by the lowers.
If it isn't straight, correct the adjustment of the lowers until it's straight.
You may need to repeat both steps, if there was a substantial bow.

If your shroud tension is too tight, you will put unnecessary strain on the
hull.

--RS