NJK MRC J/80 CREW HANDBOOK
Contents
Foreword
Boat preparation
General checks for the helmsman
Preparing the headsail
Preparing the mainsail
Hoisting and lowering the mainsail
Preparing the spinnaker
Race preparations
Near the race course
Pre-start
Maneuvers
Upwind leg
Tack
Windward mark rounding (approaching on port tack)
Windward mark rounding (approaching on starboard tack)
Leeward leg
Gybe
Leeward mark rounding (on starboard gybe)
Leeward mark rounding (on port gybe)
Returning the boat to the dock
Boat speed
Basic tuning
Mainsail trim
Jib trim
Genoa trim
Symmetric spinnaker trim
Foreword
This document is intended to help memorizing and mastering the details of good boat handling off NEC
MRC J/80 boats. The handbook is mostly based on materials in Finnish written by Eero Palomäki and
translated into English by Manne Miettinen. The text on J/80 boatspeed is quoted from the J/80 tuning
and sailing guide by Ultimate Sails (http://www.ultimatesails.co.uk/). The text on symmetric spinnaker
handling is quoted from TIPS AND TRICKS FOR SPINNAKER HANDLING by Kame Richards. All the NJK MRC
sailors are invited to improve and modify this document. Have fun and fair sailing!
Boat preparation
General checks for the helmsman
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Check that there is no water in the boat (bilge and stowage in the forepeak and stern). Dry the
boat using the bilge pump and a sponge.
Check that the boat has a protest flag, a yellow flag, a blue flag, an ‘L’ flag, a bucket, a paddle,
and sponge.
Check that the crew has sufficiently start watches, tape, tools (Leatherman), snack, drinking
water, extra clothing, but nothing extra. Place the stuff above the keel. In light air also the
forepeak stowage can be used.
Check the weather forecast before a race.
Agree about the training subject with other teams and coordinate the taking of the buoys
Check the shroud tensions by hand and check the spreader angles (?)
Double check all the preparations and go through the plan with crew to leave the dock.
Preparing the headsail (trimmer)
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Prepare the headsail before the spinnaker. Leave the prepared headsail on the deck on the port
side so that the sheets are close to the mast on the port side.
Attach the headsail sheets to the clew of the headsail with tight bowlines. You can tape the
knots to avoid the knots getting tangled in the shrouds in tacks
Attach the headsail halyard to the top of the headsail with a tight bowline. Lead the loose
headsail halyard end to the cabin outside the lower shrouds (D1). This allows the trimmer to
easily uncleat the halyard from the cockpit after the spinnaker is hoisted
In light air loosen the leech line (“snörppi”) of the headsail at the dock and adjust on water
When using the jib it is a good idea to lead the jib sheet through the genoa lead block to the
winch. This prevents sheet overrides on the winch when tacking
When using the genoa the team should have two bungee cords (with a diameter of max 4 mm)
that are attached in front of the winches. The genoa sheets should be lead underneath the
bungee cords to prevent overrides
Check that spinnaker sheets and barbers are lead correctly underneath the headsail sheets
Check that the lowest 7 headsail clips are taped so that they will not rip the spinnaker when the
headsail is lowered after spinnaker hoist
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On the water set the right headsail twist by adjusting the genoa or jib lead position: set your
lead position by luffing up slowly and watching your telltales. The windward telltales should
"break" evenly from top to bottom at the same time. If the top telltales flutter before the
bottom, the sail is twisted too much. Move the lead forward to pull down on the clew, increase
leech tension and reduce twist. If the bottom telltales luff first (or the top ones stall), the sail
needs more twist. Move the lead aft to relax leech tension.
On the water set the headsail draft position by adjusting the headsail halyard tension mark the
desired draft position with a tape on the halyard and on the mast
On the water mark the trim reference points (the acceleration mark and the full-speed mark
roughly 5 cm apart) on the headsail sheets with tape in front of the block on the genoa/jib lead
On the water mark the lazy sheet with the slack mark when the active sheet is trimmed to the
full-speed mark. Make a 5-7 cm wide taping on the sheet just in front of the winch
Preparing the mainsail (tactician)
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Lift the boom to get the lowest two sail slides (“ratsastaja”) in to the mast slot
Use a coin or a screwdriver to fasten the lock plate of the mast slot so that the sail slides cannot
slip out of the slot in any condition
Attach the mainsail halyard to the head of the mainsail with a bowline using a tight loop. It is
important to hoist the main all the way up to the black tape at the tip of the mast. If you use the
cunningham to tighten the luff of the mainsail so that the bottom part of the mainsail is folded
you lose sail area which is bad especially in light air. A mainsail hoisted high may cause the
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uppermost batten to get stuck in the backstay in tacks, you need to remember to shake the
backstay after a tack to detach the batten
Some teams alter the mainsail sheet tackle in the trainings to have less tackle in light air. This
allows for faster handling of the mainsail. NB NJK MRC Center Cup Sailing Instructions do not
allow changing the mainsail sheet tackle in the Cup matches
The fixed point (bowline) in the mainsail sheet tackle should be in the block attached to the
boom not in the block attached to the cockpit floor
Set the mainsheet ratchet block (“räikkäploki”) in the desired position (ratchet on or off)
In light air check that leech line (“snörppi”) is not too tight. Loosen it on the dock and adjust it
on the water
Hoisting and lowering the mainsail
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Before hoisting the mainsail be sure to check that
○ the boom vang is not tightened
○ the mainsheet is uncleated and can run freely
○ the outhaul is not tightened
○ the cunningham is not tightened
Lift the boom end before hoisting the mainsail so that the boom is perpendicular to the mast.
and not pointing down. This way the mainsail can easily go all the way up when hoisting.
Tie a figure eight knot in the main halyard to prevent a match loss due to an accidental tangle or
mess down in the cabin
Tie a figure eight knot in the mainsail sheet to prevent the boom hitting the shrouds in a slam
gybe
Mark the trim reference points in the mainsail halyard, the mainsail sheet and the backstay (?)
with tape
Always loosen the main outhaul all the way when taking the mainsail down - otherwise you risk
tearing the mainsail
Preparing the spinnaker (bowman)
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Check on the shore that the spinnaker does not have rips. This will save you from a nasty
surprise on the water. The easiest way to do this is to fetch your spinnaker from the sail drying
container where the spinnakers are hanging open
Rig the spinnaker for leeward hoist on the starboard. In match racing you leave the marks to the
starboard, so you want to rig the spinnaker so that it can be hoisted from the starboard behind
the headsail. When rigging the spinnaker it is a good idea to leave the headsail lying on the port
side on the deck and have the headsail sheets close to the mast on the port, so that the the
spinnaker sheets and halyard go naturally “underneath” the headsail on the starboard
Lead the port spinnaker sheet from the cockpit under the headsail sheet through the ratchet
block (be sure to check the correct direction of rotation), then to the block at the stern of the
boat and forward through the barber, outside of the shrouds and around the headstay to the
port clew of the spinnaker in the hatch. It is a good idea to pull a meter or two of extra of the
port spinnaker sheet into the hatch so that the sheet runs smoothly when the bowman attaches
the spinnaker pole to the mast
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The starboard spinnaker clew should be just inside the hatch. Lead the starboard spinnaker
sheet outside the shrouds through the barber to the block at the stern of the boat. Then lead it
back forward through the ratchet block. Check that the spinnaker sheet runs underneath the
headsail sheet and goes through the ratchet block in the right direction. Tighten the sheet so
that there is no unnecessary slack. Mark this setting in the starboard spinnaker sheet with a
tape and cleat the port spinnaker sheet.
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Leave the head of the spinnaker just inside the hatch, tape the spinnaker halyard in the bow
pulpit with 2–3 layers of tape. In the first hoist you will need to pull a bit harder. Remember to
tape again between matches. The taping is to prevent the spinnaker slipping out of the hatch in
the pre-start if the headsail is pushing the spinnaker halyard.
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Check that the spinnaker pole and the pole topping lift (“ylägaija”) lines are not tangled (lift the
pole from the pole topping lift line with your hand)
When using the genoa the spinnaker pole is placed on the deck outside the shrouds so that the
head of the pole (pointing to the bow) is resting under the genoa sheet. The genoa sheet can
rest on the top of the pole when the pole is set for hoisting. You can drop the genoa sheet in the
first gybe.
When using a jib the spinnaker pole is placed on the deck between the shrouds and the jib lead
(“fokan skuuttikisko”) outside the jib sheet
Check the condition of the tennis ball half and the knot inside the ball in the spinnaker halyard.
If either of them is not in shape there is a risk of the spinnaker going through the ring in the
mast top and preventing the spinnaker takedown which can be very dangerous in heavy air.
In light and heavy air the head of the spinnaker should tied close to the ball. In moderate winds
the spinnaker head can be 20-30 cm below the max up position.
Rig the spinnaker so that the red leech is the port leech and the blue/green leech is the
starboard leech.
You can attach the spinnaker sheet by leading the sheet through the clew O ring and tying a
figure eight knot on the outside of the sail (if the clew O rings are small, for bigger rings tie a
clove hitch and secure it with another knot). Having the knot on the outside This way the
spinnaker sheet knots will not interfere with the spinnaker pole jaws and/or the forestay.
Lead the loose spinnaker halyard end to the cabin around the lower shrouds (D1), this allows the
trimmer to easily uncleat the halyard from the cockpit when taking the kite down
Tie the spinnaker barbers together
Tie number eight knots in the spinnaker sheets. Throw the loose ends of the spinnaker sheets
inside the cabin away from the cockpit
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Tape the spinnaker pole ring from both sides to prevent the spinnaker halyard getting stuck in it
in tacks
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Check that the there is a tape between D2 and V1 shrouds above the first spreader to prevent
the spinnaker from the getting stuck in there when taking the kite down. Yap, someone must
climb…
Race preparations
Near the race course
HELM
TACTICIAN
TRIMMER
BOW
Define the
favoured side
of the race
course.
Define the favoured side
of the race course.
Mark the spinnaker
pole topping lift
position with tape. In
light air and at the
hoist the pole can
point down a bit.
Define the favoured
side of the race
course.
Measure the
starting line in
seconds.
Measure the starting line
in seconds.
Plan the strategy for the
start
Define landmarks for
the starting line and
the laylines.
Read the wind
Define and
communicate
the laylines to
the boat end
and to the pin
end
In fig.1 below the right side is favoured because of stronger wind and current. The red boat is staying on
the right, but avoiding the layline corners.
Pre-start
HELM
TACTICIAN
TRIMMER
BOW
Drive
Plan the tactics
Trim the headsail
Execute the
tactics
Give pre-processed
information to the helm
(“head to the line after
this circle”)
In light air keeps the
weight by the
shrouds
Communicate
intentions to
the crew
(“heading up”,
“bearing off”,
“tacking”,
“circling”
“gybing”, etc).
Read the time to the
start with 30 second
intervals from 4 minutes
to 1 minute, then 10
second intervals and last
10 seconds with 1
second intervals
Trim the main
Communicate the
position and the
movements of the
opponent
Estimate the time in
seconds to the line
Estimate the own
position with
reference to the
laylines
Read the wind
Tail the headsail
In final approach
sights the line and
estimates
boatlenghts to the
line
Boat handling
Upwind leg
HELM
TACTICIAN
TRIMMER
BOW
Drive and read
the telltales
Trim the main with the
sheet and backstay
Trim the headsail
Plan the tactics
near term
Keep a constant heel
with backstay and
mainsail sheet. Trim the
backstay before the puff
hits; ease the mainsail
sheet in big puffs and
sheet in just before the
puff ends
Read the pressure
and waves ahead. If
possible try to judge
whether the puff is a
lift or a header. “Big
lift in 3-2-1-now”
Judge the
distance to the
layline
Communicate
about the feel
of the boat to
the trimmers
(“Now there’s
too much
weather
helm”)
Plan the longer term
tactics considering other
boats and the windward
mark rounding
Plan the wind tactics
Observe and
communicate the
compass heading wrt the
average heading
(“headed 5”, “lifted 10”)
Balance the boat
with weight
placement. The
trimmer is the first
to go to leeward
Check that the
spinnaker barbers
are correctly set for
spinnaker hoist
(open on leeward SB
and cleated on
windward P)
Help the bow in the
housekeeping
Communicate the
position of the
windward mark
Look for more wind
upwind
Observe the
movements of the
opponent
Do housekeeping:
clear lines etc. If the
spinnaker needs to
be sorted out goes
into the cabin to do
it
Check that the
spinnaker pole
topping lift and
spinnaker halyard
and sheets are
running correctly
Help judging the
laylines
Tacking the genoa
HELM
“Prepare to tack”
TACTICIAN
Keep the weight to the
windward
TRIMMER
Prepare to release the
sheet from the winch.
BOW
Prepare to tail the new
sheet.
“3-2-1-tacking”
Turn the helm first
slowly, then faster
Tighten the main to
help the boat to turn
head-to-wind
Ease the main sheet 10
cm after passing headto-wind
Release the old sheed
when the bow is
passing head-to-wind.
Tail the new sheet
Stay on the leeward
until the boat is well
heeled
Stay on the leeward
until the boat is well
heeled
Stay on the leeward
until the boat is well
heeled
Stay on the leeward
until the boat is well
heeled
Weight to windward
when tactician says
“up”
Time and communicate
the pump “3-2-1-and
up”
Weight to windward
when tactician says
“up”
Weight to windward
when tactician says
“up”
When up-to-speed trim
the main tight
When up-to-speed trim
the headsail tight
If needed help the
trimmer by tailing the
headsail sheet
Look for wind
Keep the weight to the
windward
Anticipate puffs by
taking in some
backstay and
uncleating the main
sheet
Check the compass
heading
Prepare the lazy sheet
on the winch for the
next tack
Tacking the jib
HELM
TACTICIAN
TRIMMER
“Prepare to tack”
Keep the weight to the
windward
Prepare the winch
handle to the new
windward winch
Keep the weight to the
windward
BOW
Tighten the main to
help the boat to turn
head-to-wind
Ease the main sheet 10
cm after passing headto-wind
Uncleat the old sheed
when the bow is
passing head-to-wind
and simultaneously
trim in the new sheet
Grind the winch
Stay on the leeward
until the boat is well
heeled
Stay on the leeward
until the boat is well
heeled
Stay on the leeward
until the boat is well
heeled
Stay on the leeward
until the boat is well
heeled
Weight to windward
when tactician says
“up”
Time and communicate
the pump “3-2-1-and
up”
Weight to windward
when tactician says
“up”. If light go back to
leeward after the
pump.
Weight to windward
when tactician says
“up”
When up-to-speed trim
the main tight
When up-to-speed trim
the headsail tight
If needed go to
leeward and help
trimming
“3-2-1-tacking”
Turn the helm first
slowly, then faster
Anticipate puffs by
taking in some
backstay and
uncleating the main
sheet
Look for wind
Check the compass
heading
Prepare the lazy sheet
on the winch for the
next tack
Windward mark rounding (approaching on port tack)
HELM
TACTICIAN
TRIMMER
BOW
Attach the spinnaker
port sheet in the
jaws of the
spinnaker pole
Hoist the spinnaker
pole from the pole
topping lift
Take main
sheet in hand
when the
trimmer
prepares for
the spinnaker
hoist
Grab the spinnaker
sheets
Weight to
windward
when rounding
the mark
Weight to windward
when rounding the mark
Check that leeward (SB)
spi sheet is cleated and
leeward (SB) barber
open and windward (P)
barber cleated
Help the tactician
and bowman to get
the left corner of the
spinnaker to the
headstay
Weight to windward
When the spi
is filled find
the optimal
angle. Trim the
Take the spinnaker
corners out of the
hatch and pre-feed
them under
(leeward) the
headsail
Hoist the spinnaker
when the bow has
passed the mark
Yell “made” when
the spinnaker is
hoisted all the way
up
Let the main
all the way out
Open the
backstay
Bear off dead
downwind:
DON’T HIT THE
MARK
Attach the spinnaker
pole to the mast
When the bowman yells
“made” pull the left spi
sheet so that the pole
goes aft and is
perpendicular to the
windex. Cleat the left spi
sheet and uncleat the
right. Start trimming
with the right
When the spi is filled
pull the foot of the
headsail tight with
the sheet so that the
sail won’t end up in
the sea and uncleat
the headsail halyard
Pull down the
headsail and store in
the front of the bow
Trim the spinnaker.
Communicate about the
pressure
Check that the boom
vang, pole and
barbers are correctly
trimmed
Check that the spi is
ok (no hourglass)
Clean up the headsail
main
accordingly
on the foredeck
Put the headsail
sheet on the port
side
Check that there is
enought of slack in
the headsail sheets
Loosen main
cunningham and
outhaul
Clean up the
spinnaker halyard
into the cabin
- "siivoa" ylämerkin
jälkeen: vedä genoa
eteen, koilaa löysä
falli vantin takaa
kiertäen taakse, jos
trimmeri ei sitä ole
vielä ehtinyt tehdä
Look for puffs from
behind (the direction
the windex points)
Communicate what
the opponent is
doing
Windward mark rounding (approaching on starboard tack)
HELM
TACTICIAN
TRIMMER
BOW
TODO
TODO
TODO
TODO
Leeward leg
HELM
Bear off in
puffs head up
in lulls
Follow rule 17
Keep the crew
informed
about
approaching
luffs
Weight to
windward in a
luff
Plan tactics
Anticipate the
gybing angles
TACTICIAN
Trim the spinnaker and
communicate about the
pressure to the helm
“you can head up 10
degrees”, “bear off 20
degrees”
Ask the trimmer to
adjust the spinnaker
pole and barbers - it is
important for spinnaker
trim especially in light air
In heavy air ask for
trimmer’s help with the
sheet well in advance
Weight forward in light
air and weight back in
heavy air
TRIMMER
Look for puffs from
behind, plan wind
tactics
BOW
Stay near the mast usually
on leeward side
Weight trim
Follow rule 17
Communicate your
observations to the
helm
Look forward and observe
the opponent and winds
Be prepared to gybe
Define the laylines to
the leeward mark
with the helm
Weight forward in
light air (in front of
the mast?) and
weight back in heavy
air
Clean up lines and
prepare the kite
takedown and
headsail hoist at the
leeward mark
Help the tactician to
trim the spinnaker in
tight reach or in a
luffing battle
Weight to windward
when reaching
Gybe
HELM
TACTICIAN
TRIMMER
BOW
Weight to windward to
make the boat bear off
Weight to windward to
make the boat bear off
Weight to windward
Weight to windward.
Grasp the barbers
Drive a smooth turn
Use the sheet and guy
and help the bowman
to rotate the spinnaker
to the other side of the
mast
Detach the pole from
the mast (outer arm),
then detach the old
guy, attach the new guy
(inner arm) and attach
the pole to the mast
“Prepare to gybe”
“3-2-1-gybing”
Pull the main over
“watch the heads”
Check the mainsail trim
Find the winds, plan
tactics
When the gybe starts,
uncleat the windward
barber
Pull the (old) leeward
barber smoothly to the
deck and cleat it
In heavy air pull the old
leeward barber first to
the deck and after the
gybe is over slowly
loosen the new
leeward barber
If the genoa sheet is on
the top of the pole,
drop it
Look for puffs
Leeward mark rounding (on starboard gybe)
HELM
TACTICIAN
TRIMMER
BOW
Plan the tactics for the
mark rounding
Inform the crew about
the leeward mark
Estimate the distance
to the mark
Inform the crew if
there’s going to be a
tack right after the
mark rounding
Check if there’s an
overlap when entering
the zone
Check that the headsail
is on the correct side of
the boat wrt the
planned marked
rounding
Check if there’s an
overlap
Make sure the helm is
aware of the the
overlap and rights
when rounding
Trim the main outhaul
before the mark
rounding
Make the calls
concerning headsail
hoist and stowing the
pole
Clean up the headsail
halyard as the bow
hoists it
Hoist the headsail
Uncleat the topping lift
but don’t let it drop on
the deck
Loosen the windward
barber ca. 40 cm
Place the pole on the
deck. When using the
genoa the head of the
pole goes under the
genoa sheets, when
using the jib the pole is
placed on the outside
of the sheets
Ask for wind
information for the
beat
Grasp the main sheet
Try to keep the
spinnaker flying. You
can move on the
windward side to try
keep it flying as long as
possible by holding the
sheet out
When the spinnaker is
no longer flying tell the
bow
Check that the
spinnaker halyard goes
around the inner
shroud (D1) and can be
opened from the
cockpit
Detach the pole from
the mast and hand it
over to the trimmer
If you have time help
the trimmer in the
placing of the pole on
the deck
If you have time, hold
the windward sheet
out as a human boom
Grasp the windward
sheet and go near the
hatch
Check that the headsail
sheet in on the winch
Check the wind for the
beat
Drive a “wide in, close
out” leeward mark
rounding
Don’t hit the mark
Sheet in the main as
the boat turns or hand
it over to the tactician
if he’s free
Keep the weight on the
left (leeward) during
the rounding
At bow’s yell uncleat
the spinnaker halyard
check that it runs
smoothly but doesn’t
run too fast so that the
spinnaker ends up in
the water
Check that the (left)
spinnaker sheet runs
Gather the spinnaker
foot
Yell “falli auki” and take
the spinnaker down
Check that headsail
sheets are ready for a
tack
when the bow is taking
the kite down
Cleat the left barber for
the next rounding
Make the decision
about the next tack
Sheet in the main as
Get ready to trim the
the boat turns (in heavy headsail
air be careful more
slowly)
Trim in the headsail
when the boat is
Communicate the
passing the mark
weight placement “3-21-and up”
Weight to the
windward at tactician’s
Check the compass
“up”
course
Look for wind tell
where the opponent is
Weight to the
windward at tactician’s
“up”
Leeward mark rounding (on port gybe)
HELM
TACTICIAN
TRIMMER
BOW
Prepare the headsail
on the starboard
side
Penalty turn 270°
Returning the boat to the dock
HELM
TACTICIAN
TRIMMER
BOW
Check in
the boat
Check the
mainsail for
cuts or rips
Check the headsail and
coil the headsail sheets
Check the spinnaker
for rips
Coil the spinnaker
sheets
Boat speed
This is quoted from Ultimate sails tuning and sailing guide for J/80. This does not apply 100 % to NJK
MRC boats as they are modified for match racing and deviate in some respects from the One-Design
J/80 boats described in the guide. The most remarkable changes are the use of overlapping genoa and
lack of traveler in MRC boats. Also the mast is different so the shroud tension indications listed below do
not apply.
Basic tuning
The base setting of NJK MRC boats is fixed and should not be altered by sailors. The shroud tensions (as
measured with LOOS B tension gauge) are 30 for the uppers (V1) and lowers (D1) and 15 for the
intermediates (D2).
Mainsail trim
When you get started what you are aiming for is to power the main up sufficiently that you have a
decent amount of weather helm, but not so much that the boat cannot accelerate when a gust hits. The
principle tools you will use to do this are the mainsheet, traveller, backstay, vang and outhaul;
The outhaul should be set in light winds with a 100mm gap between the foot of the sail and the boom
and gradually tightened so that in a breeze it should be so tight that there is distortion in the foot of the
sail.
The Cunningham should be left slack until you are intermittently overpowered, then it should be
progressively tightened to remove the wrinkles from the luff, but not pulled so hard that it distorts the
sail.
In light airs, the backstay and vang will be loose and you have complete control of the sail shape with the
mainsheet and traveller. In this case you should trim the main until the top tell-tale is flying about 50 70 percent of the time with the boom held in the middle by pulling the traveller up to windward. Once
the breeze is up to the point where the boat is fully powered up and it is necessary to ease the traveller,
then you must also use the backstay and vang to help control the mainsail shape. From this point on it is
impossible to stop all the tell-tales flying, so we must use the balance and feel of the helm to help us trim
the mainsail instead.
The principle of sailing the J80 in fully powered conditions is to have the mainsheet locked off and play
the traveller through the gusts. You then use the vang and backstay to control the drive and power in
the main to balance the helm properly. When everything is set up perfectly the boat will have a
reasonable amount of weather helm. When a gust hits and you ease the traveller the boat should
accelerate easily and smoothly and the helm will feel light and sensitive almost to the point where it is
neutral - with neither weather nor lee helm.
If you have pulled on the backstay and vang too tight, then you will have neutral helm before any gust
hits and the boat will not point. Apart from feeling wrong so that you will have to push the rudder
around a lot to make the boat steer, you will notice your lack of pointing ability very quickly compared to
the boats around you. If you have not pulled on the backstay and vang enough to de-power the mainsail,
then the helm will not go neutral before the mainsail starts flogging in a gust. So you must learn to
judge from the feel of the helm, and the way the boat accelerates in a gust, whether or not the mainsail
needs more or less power. Remember that you pull the vang and backstay on to de-power, and ease
them to power up.
This leaves us with the crucial question of how much of each you should pull on to de-power the mainsail
efficiently. Generally the vang will de-power the lower third of the mainsail and the backstay the top two
thirds. You shouldn’t pull the vang on so much that you create luff starvation creases. This distortion will
consist of vertical creases running from the mast towards the clew, and it will be particularly severe
around the track feed on the mast three or four feet above the gooseneck. If you see these luff
starvation creases, ease the vang and pull on more backstay. If you have too much backstay and not
enough vang, then you will find that the sail starts to backwind low down the moment you ease the
traveller in a gust. This is because with not enough vang, the bottom of the mainsail is too full, and when
you ease it, it falls straight into the jib exhaust and backwinds.
The mainsail trim is straightforward for downwind sailing. Ease the vang and the backstay as you round
the mark, not before - otherwise you will power the mainsail up at exactly the moment you don't want
to, when you are trying to bear away. The cunningham should go off completely and the outhaul be
eased until there is about a hand's width gap between the foot of the sail and the boom. Once you are
sailing downwind with the asymmetric hoisted, trim the vang so that the back of the top batten is
parallel to the boom. Keep an eye on the top batten which has a tendency to invert which is slow! Ease
the backstay again until it has just got some load on it. Ensure that there is sufficient backstay tension to
keep the mast straight and stop it inverting.
Genoa trim
The right genoa trim of NJK MRC J80’s is quite straight forward. The genoa has the right trim when the
leech of the sail touches the tip of the upper spreader. For acceleration or very light air ease the sheet
so that the leech is 2 cm outboard of the tip of the upper spreader.
Jib trim
The J80 Jib design is sensitive to sheeting in light winds but the speed gains are significant if the trimmer
is constantly adjusting the trim. You will find that you need to set the leech line tighter as the wind
increases, to stop the leech vibrating or 'motoring'. Always pull it on the minimum amount that stops the
vibration because excessive tension will distort and hook the leech. As the sail gets older you will
eventually find it impossible to stop the motoring without tightening the leech line to the point where it
distorts the leech shape - this is the time to start thinking about ordering a new sail!
Symmetric spinnaker trim
The spinnaker is properly trimmed if the wind is flowing just tangent to the leading edge of the sail.
Don't think of the spinnaker as a bucket which "catches the wind." Just like a main or a jib, it is a foil
which bends the wind, and just like a main or a jib, the spinnaker pulls the hardest when the wind is
traveling smoothly across the spinnaker's OUTSIDE surface.
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The sheet side:
○ The luff should fold in every once in a while. This is the best way to tell that the wind is
flowing tangent to the spinnakers' leading edge.
○ The boat is SLOW if the luff doesn't fold in every once in awhile.
○ Anticipate acceleration: When the boat speeds up, as in surging down a wave, the
apparent wind will increase and swing forward. Start trimming in the spinnaker sheet as
soon as the boat starts to speed up. Be sure you ease it back out as the boat slows back
to its original speed.
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The driver should not steer to correct for these small spinnaker luffs. If you are the
trimmer, be sure you talk with the driver so you understand the drivers anxieties about
how the spinnaker is being trimmed
The guy side
○ A good basic rule is to keep the pole perpendicular to the apparent wind angle, which is
indicated by the wind indicator at the top of the mast.
○ The pole height is determined by where (in terms of up and down the leading edge) the
spinnaker first folds when it luffs. The pole is too low if the luff occurs high up near the
head. If the sail is luffing relatively low, like half way down or more, the pole is to high.
○ Be sure that you trim the sheet much more often than the pole. Although you can fix a
collapse by easing the pole, this should be the last resort. The boat seems to lose its
punch when the leading edge of the spinnaker is being constantly moved backwards and
forwards.
Halyard
○ It is best to keep the spinnaker halyard all the way up. It keeps the sail from moving
around too much.