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Steve Cockerill Coaching
supremo talks about 'trim' and how it affects boat-speed around the
course.
Steve admits this is not one of those
exciting aspects to our sport and is commonly overlooked. Why, it is
much more exciting to talk about a new tiller or mast pre bend that
makes a difference rather than where you plonk your weight on the side
of the boat. In fact when I talk about 'Trim' sailors instantly think
about sail trim. However, one area that is commonly overlooked is boat
trim. Remarkably trim can make the biggest difference to boat-speed
throughout the wind range and is usually the thing that separates the
fast sailors from the slow ones. The concepts are quite simple to apply.
but it is the one thing that can make a real difference to boat-speed
all round the course. It is easy as a skipper to be always in contact
with the feel on the rudder and be conscious of the required amount of
heel on a boat, but the crews who are probably more in control of the
trim of the boat from a weight distribution point of view, are trying to
imagine the trim of the boat without this vital piece of information.
When crewing, I used to take the tiller extension (extendable version)
from the wire for a couple of minutes at the start of the day. This
helped me get a feel for the required trim for the rest of the day or
until the conditions changed.
The principle of trim is to balance out the
forces acting on the boat through clever use of the shape of the boat
and maintain the fastest underwater hull and foil orientations for all
conditions.
When coaching his season, I have found that
'trim' has been an area where the 'big' improvements have been made by
experienced and beginner sailors alike. This article will cover aspects
like sitting forward in light winds to reduce wetted surface area to
heeling to windward to balance out the rudder, and perhaps a little more
mysterious magic:
· Fore and aft trim upwind · Light
winds
Quite
simply the slower the boat goes the less the aft sections can support
the weight of the sailor/sailors before the water flow off the trailing
edge of the transom begins to get turbulent. Sounds a good word, but
what it really means is that the water flows around the transom rather
than off it.
Commonly most boats are designed with the sail
controls in a comfortable position for medium wind sailing. Sitting in
any comfortable position for light winds probably means you are too far
back in the boat. Sitting behind the centre main for the skipper or on
the seat for the crew is probably wrong. As usual there can occasionally
be an odd arrangement. Crews in the 470 used to almost sit in the
spinnaker bag to windward and the helm right behind the centre main.
This was a way to increase the weight in the ends of the boat to stop
the boat pitching in little waves (opposite of windy
sailing).
A common problem in light winds is the lack
of feel or weather helm on the rudder for the skipper. Briefly weather
helm is the tendency of the boat to luff to the wind - normally the
centre of effort of the sails are behind the centre of effort of the
hull and foils.
Too little weather helm might make it more
difficult to follow a lift and so point high to the wind. In lighter
winds the sails/rig position tend to reduce weather helm and leave the
sailor lost for the feel they are used to. The classic tendency then is
to heel the boat to leeward to add more feel - the leeward heel changes
the shape of the underwater hull making it turn to the wind.
Unfortunately in most classes this is just slow due to increased wetted
surface area and added drag from the transom! If instead they were to
try to get their weight forward to sink the bow of the boat in, they
would also be moving the boats centre of lateral resistance forward of
the sails pushing force, creating more weather helm, without adding to
the wetted surface area. It is also clear that using the hull to turn to
boat to windward and the sailor trying to keep it on a straight line is
simply adding extra drag in the equation. This is a typical problem in
classes like 4000's where the crew and helm sit in very odd places to
get the flat planeing sections of the transom out of the water. For my
crew it was a quick dodge under the lowers and sit just beside the mast.
Also a great place to view the Jib and its tell tails. Be aware that the
crew might need a little warning to tack.
· Strong Winds
Comfort sailing rules
OK. Just concentrate on not reducing the waterline length by sitting too
far back in the boat and lifting the bow out of the water too much.
Personally I sit as far forward as I can until the boat starts to feel
like it is tripping over its bow and then I move back a little. Planeing
trapeze boats can move the weight aft, increase speed and ignore the
loss of pointing, even then the bow can be useful close to the water as
it stops the boat being knocked off course by waves
· Fore and aft trim downwind ·
Light Winds Yet again the principle is to reduce wetted surface
area. Sometimes it is the heavier sailors that can get the bow well into
the water to reduce the wetted surface area better than the lighter ones
- commonly called the boats that can carry weight. Be concerned not to
bury the bow to the detriment of waterline length, as this is one of the
more important components in calculating the potential non-planeing
speed of a boat. If you are comfortable, you are probably not far enough
forward. Check out the transom wake. If the water is not leaving the
transom clean then move forward. Don't go hanging over the back to look
at it get a friendly sailor to check it out can check theirs out at the
same time.
· Medium Winds A difficult area
moving forwards as the boats starts to stop planing and backwards as
soon as it starts to pick up. An old friend once said that he remembers
being told to sit as far back as possible, - I guess he missed the
'until the wake gets disturbed', as he and his brother sat at the back
of their mirror for a whole race and wondered why they finished at the
back of the fleet. - It's a careful balance between sinking the transom
and burying the bow
If you consider the effects of waves as well
as, the movement backward and forewords things can get quite energetic
to keep the boat on the plane. Talking to the Olympic Silver medallist
from Savannah, Sebastien Godefroid of Belgium, says he cannot understand
why some Finn sailors use anti skid strips on the aft side tanks, "if I
cannot move then I am slow!" I can remember racing downwind at Anzio in
the 92 trials in a big, fast moving Mediterranean swell. I thought I was
moving a long way forward to make the boat hook into the wave downwind -
from the thwart to the spinnaker bag and pushing on the foredeck, until
another competitor took a wave that took out half the leg from us. The
crew had stretched onto the foredeck, just inches from the Jib tack and
at just the right moment pushed the bow down into the bottom of the
swell. I seem to remember feeling a little cross that this trimming had
been a little illegal, but predominantly I felt just a little
inferior!
· Strong Winds Simply put - keep as
far back as you can to keep the bow from nose-diving. Sometimes in
extreme wind this cannot be back far enough. See Laser downwind at
Hyeres slide sent by wife from home. Europe pic might be
better?
· Sideways trim upwind. · Light
Winds As discussed earlier, some find it easier to leave a little
leeward trim upwind, especially in choppy waves. Chris Gowers is an
exponent of leeward heel. His philosophy used to be that if the boat
slowed down for an instant due to a wave or the wind, then he always had
a little righting pump in the bank to get the boat moving again.
When there is enough wind to begin to almost sit out, then there is
another trick that can be used to good effect - the gybing centreboard
trick. Back in the 80's the gybing centreboard was one of the big boat
park discussions that has seemed to gone away. Perhaps it is because I
am not sailing those classes that permit it anymore. It was very
effective when there was flat water allowing the centreboard/daggerboard
to generate extra lift by moving the leading edge towards the wind by a
few degrees. This effect can be made to work on a conventional
daggerboard boat - but it is a little tricky, so get your head round
this:
The Gybing centreboard Trick: If
you can heel the boat to windward a few degrees, remembering to sit far
forward, then use positive rudder to keep the boat on its normal course.
At first this rudder feels like a push, but as soon as the board begins
to generate lift then the rudder becomes light and neutral, but still
over to the positive direction. Effectively the boat now follows a
straight course, inline with the rudder in its positive direction. This
means that the rest of the boat, including the board is now turned into
the wind - effectively gybing to windward. Now every dog has its day,
and this trick is very useful for extra height for squeezing a boat to
windward and can be used for long periods if the boat speed does not
drop. However, once there is a lull in the wind or a slowing wave, the
effect can be catastrophic. Perhaps then the Chris Gowers' style would
gain back some ground.
· Medium Winds
The typical problem
when the wind gets stronger than the sailor can correct for, is that the
boat heels consistently. The rudder ends up behind the ear of the helm
trying to correct for this weatherhelm. This is like tying a bucket to
the back of the boat. The rudder is the biggest brake on the boat. Any
library pic for this? In turn the rudder generates more weatherhelm
as it lifts the transom out of the water, pushing in the leeward bow,
making the underwater shape even more effective at generating
weatherhelm. This problem is all a matter of style of sailing. In a two
handed boat, there is lots of adjustments of rig available to reduce the
weatherhelm, but still if you set out to sail the boat heeled to
windward, then the problem largely goes away. It was generally accepted
in the Laser that the boat would sail faster if the sailor tried not to
lean out in such a way as to keep the boat heeled to prevent them from
getting wet - better to concentrate on a good style that might not
create so much leverage but would allow the boat to be sailed flatter. I
always like to think of the rig as a weight that I would like to be on
my side of the leverage equation. In boats with lots of freeboard such
as the RS 300 this seems to work really well.
· Sideways trim downwind in
waves Reaching When considering sailing in waves down wind,
the hull form should be used to help the sailor remain in control of the
boat when the waves come from the quarter, (windward stern area). One
downwind style might be to balance out the forces on the rig with those
of the hull and board for the least drag on the rudder. But the act of
catching a wave requires more windward heel at the point of the quarter
wave reaching the back of the boat, so as to prevent the increased heel
making the boat screw into the wind - increasing the use of the rudder
and therefore reducing the chance of catching the wave.
Bearing Away (onto a run or to gybe):
When you consider the natural
forces on the boat, the bearing away action buries the bow of the boat,
any leeward heel on the boat makes the rudder a lifting plane which in
turn buries the bow, making it even harder to bear away. To compensate
for the rudder action, firstly remember to over ease the mainsail,
giving a windward heel and then the rudder can be used to good effect to
bring the boat back upright. At the same time the crew weight (that
means both helm and crew if two handed) should move backwards, lifting
the bow for an easy turn away from the wind. GYBE.JPEG. - weight back
and slightly heeled to windward.
Tacking:
In many of the single-handers I have
sailed, I have noticed the way the boat can quickly slow down in the
process of tacking, largely due to the movement back in the boat around
the traveller. This sinks the transom and acts like a break. To get
around this I have found that tacking facing backwards keeps the centre
of gravity of the sailor further forwards as the bum is heavier than the
head. It has added advantages of ease of movement, don't have to bend so
far to ovoid the boom, one foot movement and the weight moves further
forward.

Bullet Point Guide Light winds ·
if you feel comfortable sit further forward. · Try not to heel to
leeward to gain feel, instead sit further forward. · A little more
wind, perhaps try and heel the boat to windward and start the gybing
board trick
Medium Winds · Remember the rudder
is a brake, try to keep it central by balancing it out with the rig ·
Move back as the boat starts to plane and forwards the moment it starts
to stop · When bearing away - sit further back and initiate the bear
away with an over ease of the sail.
Strong Winds · Down Wind - Just
keep the bow out of the water! · Upwind - too far back and the boat
might start to skid sideways · Upwind - too far forward and the boat
will trip up on the waves
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