Julian's Skiff Tips
From the Santa Barbara Skiff
Clinic - May 2001
As some of you may know, I have just spent
the last month traveling around the world
and was presently surprised to see 29er
sailing just about everywhere. But during
the last stage of the trip, across the top
of Canada and down the west coast of the
USA, I spent considerable amount of time
talking to and addressing 29er sailors and
what follows is the gist of those sessions,
all rolled into one.
Note: More photos coming!
Rig tensions
On
the new Loos Gauge the numbers that keep
on coming back again and again,
measuring the FORESTAY are that in light
winds you should be around 17-18 (about
80kgs/180lbs), medium winds you should
up that to 20-21 (about 110kgs/240lbs)
and when it get fresher then up around
23-24(135kgs/300lbs).
Again these are all measuring the
Forestay tension.
If you go firmer than these numbers then
you risk the possibility of making your
rig to wooden, having it so strung up
that it becomes completely immobile and
it would then have no gust response.
To lose and you will suffer too much
forestay sag and your jib will simply
blow you sideways rather than drive you
forwards.
Rake
For all intents and purposes rake is
totally dependant on forestay length,
the forestay tolerance has been ½ since
Garda and we had trouble getting people
to measure there. Though I am not the
measurer, I would be stunned if it was
not checked at Kingston and I urge
everyone to check the rule and then
check there boats to make sure they
comply. Mast do compress, if you have
broken a section then it your
responsibility to make sure the boat is
still legal after it has been fixed.
Just don’t do to Kingston or come to
Sydney with out checking that
measurement.
But WRT rake, with only 14mm of play, it
virtually has no bearing on performance,
it will move the hounds about 25mm which
in the scheme of things is irrelevant,
it move 4-5 times that distance with bow
up or bow down trim, so just make sure
it measures and then get on with sailing
the boat.
Bridle Height
(Mainsheet)
It should be as high as possible, the
height we use is approx. 810mm (32”).
The reason is that this will bring the
boom the closest it can to the center
line and will also stop the boom being
dragged over the center line by a over
enthusiastic crew both of which maximize
the amount of power you can generate
without putting a brake on when you
least need it.
Main and Jib sheet tensions
If there was one thing I said move than
anything else over the 2 weeks in NA it
was pull the sheet on.
Setting the jib sheet. The 29er has a
short luff/leach and long foot with a
reasonable amount of roach in the leach.
First, the tack of the jib has to be pin
into the forestay fitting, don’t go
adding lines or shackles.
Second, go sailing before the start and
adjust your jib luff tension so that you
have eased it so there is just the hint
of scalloping between the jib buckles,
then tighten the jib halyard (the wire
bit) about 15mm tighter from that
position. Once you have found that spot,
mark it on the back of the mast and not
that this is the right position for that
strength of breeze. If you are sailing
in lumpy water with waves then you may
only pull the halyard another 5-10mm if
at all because a loose luff with keep
the camber forward and give you extra
drive. If you are sailing in dead flat
water then you will pull it hard because
this will flatten the luff and make the
entry low drag.
Thirdly, in light air you should be in
the top hole of the clew board, medium
air in the middle and you normally would
not get to the bottom hole until its
blowing the “oysters of the rocks” (this
is skiffy speak for real fresh, very
strong wind). Again in lumpy water you
would delay the moving out of the top
hole.
Now you are in a position to set you jib
sheet tension. The way this should be
judged is that both the upper and lower
jib tuffs should break together, if it
has been set perfectly. For those not
fully ofay with this concept then send
your skipper to leeward, get him to
place his head above the outer leeward
grab rail and looking up the jib leach
should run basically straight up from
the clew and be inline with the outer
tip of the spreader as it passes that
point and then simply ach in to the
head.
This will be (in most cases) substantial
tighter than where most crews are
setting their jibs. The problem with all
skiffs is that they like to run, they
feel great when you crack them off a few
degrees but in terms of getting to the
top mark, all you do if you crack them
off is you end up bearing further and
further away, you end up chasing your
tail. By sheeting the jib in harder, you
will set it correctly but you will also
force your self to sail higher (and
possibly slower through the water) but
you will get to the top mark sooner and
in a more disciplined manner.
And lastly, unless it is really fluky
and you are an absolute genius then just
set the jib sheet and don’t play it. The
hardest thing in a 29er is that they
move quite quickly and things change
very fast. You need something to remain
constant so that the poor skipper has
something to steer to, some reference so
that he can keep the boat pointing in
the right direction most of the time.
Mainsheet tension
Look up! Both going upwind and downwind
the absolute determinate of mainsail
twist is the upper leach ribbon. If you
are sailing up wind and the upper leach
ribbon dose not occasionally (10-20% of
the time) want to flick around to the
leeward side then you are too loose and
I bet that is the case of 90% of you.
Sure if it is spending 50->% of the time
glued to the leeward side then you have
stalled the upper main and you should
ease it a bit. You need to set vang (see
below) to set the twist so that the
lower main is in but upper main is set
by vang and mainsheet so look up.
Down wind, with the kite up, then the
general rule if you are running lose is
the main should be over the ¼. That the
leeward aft corner of the boat.
There is absolutly no truth in the rumor
that if you ease the main you will break
the mast, you can safely ease it out ½
way (to the stays).
But what I would urge everyone to do is
tie a knot in the mainsheet so that the
boom can never hit the shrouds, that is
one way to lever the mast out of the
boat. Spectacular but expensive!
Last but not least, jib sheet angle
Put the pin in the center of the three
adjusting holes and leave it there. Any
possible gain will be out weighted by
the hassle and uncertainly of fiddling!
Mainsail Downhaul
(Otherwise know as Cunningham) On a 29er
(and a 49er) because the main sail is
fully battened, the downhaul becomes a
extremely effective flattening tool
because if you think about the line of
the load of the downhaul as it is
applied, it will run up through the mast
sock and then up through the sail some
distance aft of the mast. Why, because
the shortest distance between two points
is a straight line and with any
mainsheet or vang tension that will be
behind the mast, plus with full length
batten it will move even further behind
the mast so when you pull on the
downhaul you can and will “bowstring”
the mast. A bit like the string on a
bow, the tension line will increase the
bend.
So you should be looking at Downhaul to
flatten the over all camber in the sail
but particularly in the upper sections
of the sail where the mast is smaller
(diameter) and also less supported.
One exception top the rule is in very
light winds where the initial
application of downhaul will infact
induce camber low down but this is
because it will clean up the lower main
rather than anything else and this is a
good thing as long as it is used
sparingly.
In flat water and steady wind you will
use downhaul earlier and more of it than
in lumpy water or wind, this is because
it dose flatten the whole sail and if
you want drive rather than low drag
then, again use it sparingly. Good idea
to put a set of numbers down the side of
the mast so that you can repeat settings
from one beat to another. But of course
you need to pull the mainsail up to the
same point each time.
Vang (Kicker)
29er vang is very effective, it is very
powerfully and holds the boom very
rigidly. As a general rule Vang will
also flatten the whole sail because it
pulls down on the leach and that pulls
the mast head aft which bends the mast.
But it dose it by driving the ram
upwards and forwards so the ram also
bends the lower mast forward and
therefore will flatten the lower main
first.
The way I set it up is to sail up wind
without it until I find my comfortable
position (mainsheet tension) and then I
snug the vang up so that when I ease the
main sheet the boom moves out rather
than up (so to speak).
As the wind freshens then more and more
vang, as it backs off, less and less
vang.
My trick so that I know how much vang I
have go on is to run the tail end of the
vang (down where the 2:1 block attaches)
back up through the exit block on the
boom and then back along the boom. At a
point somewhere above the ratchet block,
I tie it to a piece of shockcord (bungy)
and then the schockcord to the back of
the boom.
So as I pull the vang on the knot moves
forward, and again use one of the
Ronstan number scales against the knot,
you can work out how much vang you have
got on.
And again, steadier the wind and flatter
the water, more vang sooner so the whole
sail work as a single foil. In rough
water and or wind you want the sail to
twist more so you need to use it more
sparingly.
And the old “skiffy” rule, when the
going gets really tough, oysters off the
rocks material, then if you don’t ease
it you will simply fall over.
Two last things, both with the vang and
with the downhaul, it’s a good idea to
ease them down wind, not because you
will break the mast (neither will) but
because easing both controls will allow
the sail to bag back up again and if you
want speed that’s a good idea and WRT
the vang, getting some of it off before
you bear away will allow you to do that
corner with more grace and style and
speed, more aplomb than if you do not.
Don’t let it go to far or you will loose
the upper leach and that will make it
very tough in the gybe.
And if you happen to capsize with a lot
of vang on, and you are very
enthusiastic getting the boat back up,
you can break the mast. Very simply
water is 1000s of times denser than air
and that amount of pressure has to go
somewhere.
Outhaul
29er has no overlapping jib, therefore
there are no taboos about having to have
the main strapped tight all the time.
If you are lacking pressure then easing
the outhaul up wind so that you have say
100-150mm (4”-6”) of camber off the boom
is a good thing.
As the wind increases and you start to
get over pressed, then sure, bring it
back on, but its all good horse power
(kw) low down and its all good stuff.
Two sail reaching 200mm (8”) camber is
great, even 3 sail broad reaching
150-200mm is going to help.
Obviously if it is fresh then set and
forget, you should have better things to
do, like keeping the boat upright!
Body stance in the boat
Now I am going to get personal, when we
went sailing out of San Francisco Yacht
Club, it was quite fresh, be seas, all
in all quite challenging.
29ers are light but highly powered, but
light means that if they hit a wave the
wrong way or are trimmed (boat wise) and
plug into the back of a wave they will
stop. A youngish girl who was normally a
skipper but was crewing in this
instance, who’s name was Molly and who
surname I won’t go into details, was
just fantastic, she was moving forward
and aft, in-tune with the waves and
punching this boat over the difficult
seas to the point that even though there
was not much of her, they where going up
wind higher and at the same sort of
speed as there heavier rivals.
So what do I mean? Going to get a bit
technical now. A 29er with a 140kg (308
lbs) crew on board plus the boat sails
foils spars and the rest of the
paraphernalia weighs in at around
230-235 kgs ((500-520 lbs). It is design
to float a static weight when it hits it
mark of about 180kgs (400 lbs) so when
the boat is stationary it sinks about
12-20mm (1/2 – ¾ “) further into the
water than it should.
This is no problem because as soon as
the boat gets any way on it can easily
dynamically support the extra weight,
well before planning.
So in light winds when there is not much
wind about it is important to understand
that you have to optimize the boat for
those conditions. If you sit in the boat
where you normally would sit in normal
conditions then you will sink the
transom, so go forward young man (or
girl). If you look where we supply the
non skid on the gunwale it goes well
in-front of the shroud and so should
you.
There is no reason why the crew should
not sit on the mast partner or even
in-front of the jib track in light airs.
God was very nice to sailors and gave
them ears and eyes, if you see or hear
the bubbles or wake from the transom
then you are to far aft. Very simply
indubitable rule.
You can push the bow down 100-180mm
(4-7”) without significant drag increase
in light wind and low hull speeds, the
boat has been design to do this and sail
well like this, for those who read my
fathers pontifications this is what he
calls the 4th mode.
The reason it works is that the increase
in drag from pushing the bow further
down is greatly out weighed by the
reduction in drag from a reduction in
surface area and reduction in form drag
from having a transom driven to deeply
down.
Obviously as the wind picks up, you come
aft, but the crew can quite feasible
still be infront of the shrouds up to 10
knts. And then as the boat moves faster
and faster the futher aft you move.
This holds for up wind as well as down
wind and as you tend to move faster down
wind, you will be moving further aft,
down wind for a given wind speed than
you will be up wind.
To say that X immersion of the bow is
correct is obviously a impossible
statement because it will depend so much
on hull speed but the boat floating on
its marks would have the toe of the stem
immersed 40-45mm (1 ½ - 1 ¾ “) and the
transom submerged 12mm ( ½ “) at 5-6
knts.
So back to Molly, what Molly was doing
was moving her body weight to lift and
lower the bow as it came to each of the
wave and also pump the mainsheet to work
the boat over each wave. In these
conditions there was plenty of wind and
plenty of speed so there was absolutely
no risk of the transom ever sinking in.
In flat water she and her skipper would
have been ½ the way back along the boat
and planning hard up wind. But because
the water was lumpy, the excess drag
from the bow plunging down and into a
wave or from it rising to high and the
boat seeming to “stall” was overcome by
Molly moving here weight to smooth out
the rises and falls and keeping them in
sync with the wave frequency.
This another thing that sailing fast
boats throw at you, if you move slowing
across waves then there is plenty of
time for the water to react with the
boat and the boat naturally contours
with the waves. 29ers and more so 49er
move way to fast for the water to have
anywhere enough time to sync in and in
most cases go right out of sync which
results in the nose plunging into the
wave face ahead.
You have to use your weight and the
sails to get the boat back into sync and
once you have developed a good technique
then it will enhance you slow boat
sailing also.
Heel
29ers are not round boats they are
effectively a long shaped wedge with
hard corners. Those hard corners aft are
what allows you to drive the boat very
hard in a lot of wind and enjoy those
screaming rides at speeds that you did
not think where possible but they do
have there draw backs.
In light air, you need to get them out
of the waters so you move forward and
lift them out.
Once you start moving a bit faster and
you are back in the boat then you can
lift them out so you must KEEP THE BOAT
FLAT!
And Flat is FLAT, +/- 5 degrees is
acceptable, +/- 10 degrees is only just
tolerable but by the time you get to 15
degrees then the reason you are at the
back of the fleet is very obvious.
The good guys will sail the boat upwind
and down wind with the boat within +/- 5
degrees all the time and most of the
time if they are heeled its to windward
and not to leeward.
There are some reasons for this but
without getting too technical, they
are:-
#1 The boat is design to be most
efficient in one mode nad that is
upright.
#2 When you heel a roundish boat, bit
like if you heel a round ball, nothing
much happens but as you heel a 29er type
wedge then as you heel it more and more
you screw the water line and the centers
of buoyancy so that they form more and
more of a curve and it is in that
direction of that curve that the boat
wants to travel.
Going upwind if you heel the boat to
leeward then the boat wants to round up.
Heel it to windward then it wants to
bear way.
The reason the good guys heel there
boats to windward up wind is so that
they use the hull to neutralize the
windward heel that you should get if the
boat is properly in balance and also it
make the boat crab to windward and makes
the crew want to trim the mainsheet in
further.
But most importantly, when a gust hits
the boat, by the time the crew has eased
the sheets and swung right out the boat
will have moved from heeled to windward
to bolt upright which is the very best
position for the boat to be in and
exploit the gust to the maximum
capacity.
Down wind, its spooky to heel the boat
to windward and you have to have a great
rapport between the crew and the skipper
but because you now have a spinnaker
hanging out the front, it makes the boat
want to bear away and therefore gain
depth, but it will load up the tiller
and make the helm very sensitive.
If you are trying to make a wing mark
and need height, you are better off
heeling the boat to leeward.
Only time that heeling to boat
excessively to leeward works is if you
need to gravity fill the sails in light
airs.
Julian Bethwaite
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