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Sonar Tune and Trim Guide
Rig Tune
We
recommend checking your shroud tuning before going sailing. Start
by checking that the mast butt is between 920 – 930mm from the
companionway sill. Check the rig tension with at least 1-inch of
mast block behind the mast. Tension the upper shrouds to 275 pounds.
To check that the mast is centered, hoist a steel tape measure on
the jib halyard and measure to marks on each rail equidistant from the
stem.
The next step is to take the slack out of
the lowers so that the mast is straight side to side. From there you
can ease the lowers a few turns each for light air knowing that they are
at least even.
The headstay length should be between
25’11" and 26'. Check your headstay by measuring from the
bearing surface of the T to the center of the pin.
Tuning before the start
Sailing before the start is the
best time to evaluate your set up. Once you are in the starting
area, it is a good idea to find another boat that you are familiar with to
sail close hauled on both tacks. It is important to make sure when
you’re tuning up before the start that the entire crew is focused on the
proper weight placement for racing trim. This will be your best
opportunity to evaluate your boat speed and determine if you need to
change something. It is also a good idea to immediately have someone
monitor compass headings on each tack to determine lifts and headers while
also evaluating boat speed.
We like to start by trimming in on the main
and jib sheets with the boom at or above centerline and the leech of the
jib trimmed about three inches from the tip of the spreader. The
first thing to evaluate is your headstay sag and jib halyard tension.
Start with a little scallop in the luff of the jib. If you feel as
though your head stay is too tight and your backstay is slack, you will
need to add another chock behind the mast. Typically, We sail with 1-½
inches of chock behind the mast in light air and you may find you’ll
want to add even more chock behind.
It is best to begin sailing in light air
with a fairly saggy headstay and need to put a little tension on the
backstay in order to take some of the pump out of the head stay. It
is important to note that the more headstay sag you have the better you
will point. We aim for 5 inches of headstay sag in light air.
If you seem to have plenty of height and need more forward speed it could
mean that your headstay is too loose and you should tighten your backstay
a little bit. Remember that the backstay is really your fine tune
headstay adjustment in light air because the aft blocks are keeping the
headstay loose.
We find that too many Sonar sailors are
sailing around in light air with their backstay bouncing around. If
the backstay is bouncing around, then the entire rig is going to bounce
around. The key is to have enough mast chock behind the mast in
order for you to keep some back stay tension and still have a loose head
stay. Trial and error is the best way to determine the correct
amount of mast chocking for each set of conditions. This is why it
is important to fiddle with these adjustments before the race so that you
are optimized by the start.
After setting your mast blocking for light
conditions, you’ll find if you sight the mast that you could have from 2
to 3 inches of fore and aft pre-bend. It is a good idea to sight up
the back of the mast while sailing to windward to set the tension of your
lowers. ¾ inch of sideways sag at the spreaders is about right for
light to medium conditions.
As the wind increases to over 15 knots the
lowers should be tight enough to keep the mast in column. Remember
if you take out a mast block from behind the mast as the breeze increases
your lowers will most likely need to be tightened a turn or more. You’ll
probably still want at least 1-inch of block behind the mast in heavier
wind speeds.
Mainsail Trim
We find that once we have the mast
blocking and lowers set for the wind speed, then the outhaul is the next
best way to control the depth of the mainsail. The more pre-bend
you are using the looser you’ll need to have your outhaul in light air.
This is why it is good to have another boat to tune with while you’re
making these adjustments. We like to sail in light air with the shelf foot
open about 3 to 4 inches. The shelf foot should be closed in wind speeds
15 knots or higher.
We don’t recommend using any cunningham
in the mainsail until wind speeds are over 15 knots.
It is okay to set your traveler so that
your boom is above centerline. It doesn’t really matter if the
clew ring is on or above centerline. What matters is if you have
enough weather helm. I like to have a little pull on the tiller in
light air so that the boat is trying to go to weather and I am trying to
foot fast forward with the tell tales streaming straight back.
Once you have the mainsail controls
adjusted to your liking, in very light air, 2-5 knots, we like to keep the
leech tell tale at the top batten flying half of the time. Another
good test of the correct amount of mainsheet tension in light air is that
the top batten should line up with the boom straight fore and aft.
Remember it is easier for the wind to flow around a flatter more open
camber section than a full closed section in the light wind speeds.
Certainly, once the velocity picks up to 8
– 10 knots or more, you can get away with sheeting the mainsail harder
and sailing with the top tell tale stalled most of the time and the batten
hooked to weather in max power conditions. The reason this
works as the wind speed increases is that there is enough force in the
wind to bend around this more tortured shape without stalling. What
you’ll also find is that as you tension the mainsheet, as the wind speed
builds from 6- 8- 10- knots and above, and the crew moves up on the rail,
keeping the boat flat, that the mainsheet and leech tension now causes the
back stay go slack and the headstay tightens. This is fine as long
as the boat maintains top speed. It is best just to leave the back
stay alone and set for the light spots so that when you ease the main out
again, the slack goes out of the back stay which is set for the correct
headstay sag for the lighter wind speeds. This is also why it is nice to
have a reference mark inked onto your mainsheet so that you can repeat the
fast setting at a later time.
In the heavier wind speeds over 15 knots we
recommend leaving your traveler fixed on centerline and playing the
mainsheet and backstay in the puffs. It is also a good idea to use a fair
amount of vang tension as well so that the leech of the main does not
twist too open when the mainsheet is eased in the puffs or reaching and
running. We recommend setting your vang tension so that you have enough
leech tension while reaching before the start so that you can accelerate
off the line.
Jib Trim
It is nice to have marks on your
spreaders three and six inches in from the tip. The outside mark is
your best light air reference mark. The inside mark represents
maximum trim in 10 knots and above while maintaining top speed. The
leech telltale should fly all of the time.
Halyard Tension
Most Sonars are fitted with jib halyard fine tune deflectors. It’s a
good idea to place a mark on your halyard course and fine tune so that you
can repeat the settings. As a general rule of thumb if you are
sailing in light air with a lot of head stay sag, 4 – 6 inches, then
you’ll want to have a very loose halyard with some scallops in the luff
of the jib. As the wind speed increases from 6 –8 –10 knots, the
headstay becomes tighter due to increased mainsheet tension. The jib
halyard should generally should be tightened to remove most of the
scallops in the luff so that 12 knots you’ve taken virtually all of the
slack out. Typically, when the wind speed is in the 5 – 10 knot
range you will need to ease the jib halyard fine tune after you tack,
especially if you have tensioned it during the previous tack. This
is because your apparent wind is less after the tack and the friction in
the luff tabs is released during the tack.
Jib Leads
We generally like to set the jib
leads so that the telltales break evenly at the top and bottom.
Generally, we don’t think you’ll need to move the jib leads more than
one or two holes back as the wind speed increases. The biggest
reason for this is that you are tensioning the halyard as the windspeed
increases, which is raising the clew at the same time.
Crew Weight
In light air we like to have the
crew bunched forward in the cockpit as close to the bulkhead as possible.
It is okay to sail the boat reasonably flat in light air upwind as long as
you have enough helm. The more you heel the boat the more you will
generate windward helm. Because of this, we like to sail with about
5 degrees of heel in the lighter windspeeds. As the wind speed
increases you can sail flatter and still have helm. However, we
always try to keep the crew weight forward in the cockpit for all wind
speeds.
Roll Tacking
You will want to practice roll
tacking with your crew before racing. This means that the mainsail
trimmer should tack the traveler and the jib trimmer tack the jib while
sitting on the old weather rail. The helmsman and the other crew members
should then cross the boat together. In light air that may mean the
crew just moves into the seat on the leeward side and forward even if the
helmsman is the only person on the weather side. . You may want to
position one crewmember in the center of the boat over the keel just aft
of the companionway. Roll tacking and crew weight placement is
critical to light air speed ands performance.
Downwind
For starters, we generally
recommend a bear away set with the pole to starboard in light air.
Primarily because a gybe set is too abrupt a maneuver in light air.
Save your fancy gybe sets for the windier races when the velocity will
help accelerate your boat again after the 180 degree turn.
As a rule of thumb, the optimum gybe angle
downwind in light air is the reciprocal of your upwind heading. In
other words we like to use the boats still going upwind on port tack as a
guide to which angle we should begin sailing downwind. In light air
this is usually the best angle to sail. As the wind speed increases
you can begin sailing lower as long as there is adequate pressure on the
spinnaker.
When you first hoist start with your pole a
few inches lower at the outboard end so that the spinnaker fills quicker.
Also make sure the jib is eased around the mark so that it does not stall
and blanket the spinnaker in the hoist. Lower the jib as soon as
possible in light air, even if it drops in the water for a few seconds,
since all the time it’s up it is blanketing the spinnaker.
We generally don’t bother to ease the
outhaul downwind. We leave it in its upwind setting. The
outhaul is a much more important upwind adjustment than downwind. If you
do chose to move it make sure you have a reference mark on the tail so
that you can get it back to the upwind setting.
Vang tension is critical down wind.
Initially we set the vang tension for reaching around the starting line so
that we have leech tension when we are trying to accelerate off the
starting line. Most likely you will need to ease it once you begin
the first downwind leg. We try to keep the leech telltale flying as
we do upwind. If the leech telltale is stalled try easing the
mainsheet and vang until you achieve some flow off the top batten.
In real light air the weight of the boom will generally close the leech
down. Naturally, you want a bit of slack in the vang in this
condition so that the main will perhaps open up a bit when you are gybing
at 90 degree angles with the apparent wind direction about abeam.
We like to heel the boat about 5 degrees in
very light air downwind as well since it helps keep the spinnaker away
from the mainsail and may reduce some wetted surface. Once the wind speed
is over 5 knots you can flatten the boat out since the pole will just then
begin to come back off the headstay.
Make sure the leeward twing is off in light
air. Once the wind speed reaches 12 knots you can set the twings up
about 15 inches and leave them from gybe to gybe since the pole is squared
back and the clew of the spinnaker is near the headstay.
When you hoist the jib to prepare to round
the leeward mark, make sure the sheets are eased all of the way so that if
anything the jib goes up luffing. If the jib is over trimmed at all
then it will disrupt the flow over the spinnaker and cause it to collapse.
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For
more information or to order Sonar sails:
1) Contact |
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Jud
Smith
Doyle Sailmakers, Inc.
(978) 740-5950 |
Sarah
Hitchcock
Doyle Sailmakers, Inc.
(978) 740-5950 |
2)
Contact your local DOYLE loft
3) Email us at
sarah@doylesails.com
4) Call us at 1-800-94-DOYLE
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Doyle Sailmakers One Design Division
Your One Design Specialists |
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