purpose of this tuning-guide is to give our clients in the H-Boat class
some guidelines on how to get the most out of their North Sails. The
tuning guide is made by Steffen Stegger, Lars Christiansen and Theis
Follow the guidelines, but always experiment and try finding your own
trim. The weight of the crew, the balance of the boat, the stiffness of
the mast together with specific local wind and sea conditions all have
influence on the fastest and final trim.
Before stepping the mast in the boat, some very important measurements have to be made to follow this tuning guide.
The length and angle of the spreaders are important to the shape of the
main, they help to control the bend of the mast and thereby the tension
of the forestay. The length of the spreaders is measured from the side
of the mast to where the shroud passes the spreader, the measurement is
81 cm measured along the middle of the spreader. The spreader angel is
measured by fixing a fine line between the two top shrouds, measure from
the line to the aft side of the mast, the measurement is 19 cm. Next
make two tape marks on the spreaders at respectively 44 and 54 cm from
the side of the mast. These are used to trim the jib.
Lead the upper shrouds and forestay along the mast, the upper have to
be out of the spreader tips. Pull them as hard as you can and put a mark
on all three wires at the height of the black mark at the gooseneck.
These three marks are now used to check if the mast is straight from
side to side in the boat, and to check the mast rake. The mast is then
3. The foot of the mast is placed so
that the distance between the center of the forestay pin to the front
edge of the mast is 2,42 m.
4. Control that the
distance from the top of the gooseneck mark to the deck measured along
the side of the mast is 54,8 cm any possible difference should be
adjusted when setting the forestay in the next step.
5. The mast rake is set so that the distance from the mark on the forestay to deck measured along the forestay is 1,37 m.
Now that the correct mast rake has been set, control that the mast rest
on the full surface. If this is not the case, the pressure on the rig
will become uneven and the forestay unsteady.
The marks on the top shrouds (from step 2) are now used to control if
the mast is placed in the middle of the boat. This is done best by
measuring the distance from the mark to the deck. This should be the
same on both sides.
8. Rig tension is somewhat
difficult to define, because not everybody has the same meter to
measure. We have used a Loos Gauge type PT-1 M. See the On the Water
9. The lower shrouds are
tensioned, so that the mast is completely straight in the boat up to
20-22 knots. From here on tighten them till the mast drops 5-10 cm off
to leeward at the forestay fixture - the exact measure depending on crew
1. The mainsheet is the
most important factor when trimming the main. Even minor adjustments
can have a big effect on speed and pointing. If the sail is sheeted hard
the leech will close more and increase rudder pressure, but the
pointing ability will be improved. This can be used in middle air and
flat water as long as the boat can be hiked flat. In light wind the
mainsheet is eased so that the tell-tale by the top-batten flies
straight aft. In heavy winds the mainsheet is pulled very tight and the
H-boat Tuning guide backstay is pulled until the boat becomes light on
the rudder again. As the waves increase more twist is needed to
facilitate steering. At the same time it improves speed and hereby
pointing. As a thumb rule trim the aft part of the top-batten parallel
to the boom in all wind strengths.
outhaul is also an important factor when trimming as it controls the
draft in the bottom of the mainsail. In light winds (0-4 knots) the sail
should be 3 cm from the mark. In a little more wind (4-10 knots) about
1,5 cm from the mark and in more wind than this pull the sail all the
way to the mark.
3. Avoid using the Cunningham
in light winds. In middle winds pull only so much so that the wrinkles
disappear. In winds above 14 knots pull the Cunningham hard to open the
leech and the draft forward.
Adjustment of the traveller affects rudder pressure and
depends on the crew weight. The traveller is adjusted so that the boom -
as long as possible- is kept parallel to the centerline. This is to
keep maximum distance between the main and the jib. As the wind
increases and the backstay is pulled let the traveller to leeward until
the boat is balanced and light on the rudder.
The backstay has two functions: To control mainsail depth and to
control forestay sag. This means that a tighter backstay flattens and
opens the mainsail, gives less forestay sag and hereby a flatter jib. We
have put marks on our backstay every 5 cm, so we can return to good
trim after mark rounding etc.
6. The kicking
strap is used upwind in heavy winds to bend the mast and hereby opening
the sail in the bottom part. It also keeps the leech from opening too
much when easing the mainsheet in the gusts. Never use the kicking strap
upwind in less than 16 knots. Remember always to ease the kicker before
going downwind to prevent the boom from breaking. When reaching, set
the kickingstrap so that the aft part of
the top batten is kept parallel
to the boom.
1. Lib Lead
As a general rule set the jib lead at a distance of 2,88 m from the
forestay pin to the center of the block. The jib shall luff evenly along
the luff of the sail. This means that the telltales should break
evenly. If the waves are big in more than 6 knots move the lead 1-2
"holes" forward and if the wind is less than 6 knots up to 5 "holes"
2. Sheet Tension
To trim the jib, use the marks set on the spreaders. In wind strengths
that are less than 6 knots use the mark at 54 cm from the mast in more
wind use the inner mark
3. Halyard tension
Never over tighten the halyard, as this will move the draft to far
forward. Pull as much as to remove the creases, but not more. In light
winds leave some creases at the
luff, as this will cause the draft to
move aft, thereby increasing depth.As a general rule set the jib lead at
a distance of 2,88 m from the forestay pin to the center of the block.
The jib shall luff evenly along the luff of the sail. This means that
the telltales should break evenly. If the waves are big in more than 6
knots move the lead 1-2 "holes" forward and if the wind is less than 6
knots up to 5 "holes" forward.
The height of the spinnaker pole on the mast should be 1,50 m over the
cabin top roof. The pole is kept horizontal in most conditions. This
makes it possible to take full advantage of the whole pole length,
keeping the spinnaker as far away from the other sails as possible. Our
GRADIENT spinnaker is designed for this.
In light winds the pole height is adjusted to keep the clews at the same
height to get the best angle of attack on the windward leech and
keeping the leeward leech open.
In heavy winds on a tight reach, the spinnaker pole should at no time be
closer to the forestay than 60 cm to prevent the boat from coming out
If you have any questions regarding trim or H-Boat sailing in general, please contact Theis Palm.
Good luck on the water!