STEERING ON A WINDY RUN
by Kame Richards
This is a distillation of a seminar Scott Owens and I gave at the Metropolitan Yacht Club of Oakland back
in 1989 or 1990 as part of a series of seminars designed to help prepare participants for MYCO's annual
400 mile downwind race from Oakland to Catalina Island in Southern California. The race course runs down
the Northern California Coast, past Point Arguello and Point
Conception, a very windy piece of coastline! It is the intent of this article to help you develop skills for driving
while sailing windy
runs.
Let's jump right into the subject by looking at what a sailboat wants to do on a windy run. Imagine sailing
a run on starboard jibe, which I will also call starboard pole, meaning the spinnaker pole is on the right
hand side. If the boat heels to port (boom going lower, spinnaker pole going higher), the boat wants to
turn right. On the other hand, when the boat heels to starboard (pole going lower, boom going higher),
the boat
wants to turn left. The former circumstance, left unchecked, leads to a "round-up," an un-controlled turn to the right, while
the latter leads
to the much more spectacular "round-down."
Before we go into more detail, let's remind ourselves that in general, moving the rudder causes the boat
to slow down. The reason we need to pay so much attention to heel angle is that it transmits an early announcement
that the boat is about to turn. If we do not like the turn being indicated by our heel angle, we can make
corrections before the boat even starts to turn the corner. Early corrections can be small, requiring little
rudder movement, and consequently won't slow the boat down. If we like the change in heading, we try to
maintain the heel angle until the boat has achieved the desired new heading, and then make small corrections
to straighten out the boat to continue on the new heading. When it is blowing hard, and subtlety is no
longer required, you still are dependent upon heel angle to give you the advance warning you need telling
you what the boat will
do next.
In fact, almost all steering corrections can be decided based on angle
of heel alone.
Now let's imagine what the ocean is like. On close examination we will see that there are waves moving
across the surface. The tricky thing about waves is that they don't hold still. So let's consider a photograph
of a wave. It looks like a small mound. If the mound were made of dirt, we could take a bicycle up to the
top, point it towards the bottom, pick up our feet and, to no one's surprise, we'd start rolling (coasting)
down the hill. The taller the hill, the faster we'd go, as long as we didn't fall over. The same holds
true for a sailboat on a wave, except the wave has the potential of moving along under the boat for some
length of time.
So, here we are, in our imaginary boat in our imaginary ocean, and it is nice and windy. We are sailing
on starboard pole. What do we need to do to get surfing? We need to realize that the waves we are interested
in surfing are traveling faster than our boat. So we need to keep the boat moving fast between the waves
by reaching just a little (in this case turning right). If the boat is going too slowly, the wave will
pass under the boat
before we have spent sufficient time "coasting" to develop enough speed
to stay on it for any length of time.
There are just two simple rules of surfing when it comes to sailboats. Rule #1: Keep the bow lower than
the stern. Rule #2: Keep the boat right
side up.
Let's talk through a wave cycle from the boat's point of view. At the top of the wave, you need to be
reaching, sailing a little high to keep the speed up. The waves are traveling faster than the boat, so
the wave starts to pull out in front of you. Because you are reaching, as the stern begins to drop into
the trough, the boat will begin to heel to windward (to the right). As we saw above, this heeling will
initiate a turn left. Carefully allow the boat to turn to the left. This will align the boat with the direction
the wave is traveling. The next thing that happens is that the stern is being lifted by the next following
wave in the sequence. The bow should be aimed straight into the trough, and the boat will start to speed
up. Now you simply execute the two simple rules of surfing mentioned above until the wave starts to pull
out from under you again. Then turn
right to get the boat into the "ready" position, as at the beginning of
this paragraph, reaching across the top of a wave.
Since we will be referring to these steps or positions for the remainder of this article, let's give them
numbers:
- Ready position reaching on the top of a wave.
- Bear off maneuver as wave moves out from beneath the
boat.
- Takeoff alignment.
- Takeoff.
- Surfing.
- Losing the wave.
- Go to step 1.
The two most precarious steps are #2 (bearing off), and #6 (losing the wave). Bearing off is a bit risky
because it is easy to let the boat turn
too far. On the "normal" scheme of things, since the boat wants to turn left on its own, our tendency is to stop it from
turning. But if we stop
the turn, we are poorly positioned for steps #3 and #4, and we will start "wallowing" (rolling from side to side) and making
large steering corrections as wave after wave passes under the boat. Keeping in mind that we are on starboard pole, if we
get to step #4, where the boat is on the face of the wave, and we are still reaching somewhat, the boat will begin to heel
to leeward, causing it to want to turn further to the right. It will take a monstrous steering correction to bear the boat
off in this circumstance. In this position it is usually better to let this wave go by and get repositioned for the next
one.
Takeoff alignment (#3) requires a lot of visual input, looking from side to side as the stern is being
lifted, looking constantly for cross chop which might lift the bow at the wrong time and prevent the takeoff
because the bow is not low enough.
If the boat has been properly aligned for takeoff, the takeoff itself (#4) is trivial, requiring almost
no steering. Just go straight ahead,
and watch the speed build! Maybe you should "feel" the speed build, as there are much more important things to watch than
the knotmeter at a time
like this.
Throughout all of this we have to find some path across the water to try to keep the bow down and the
stern up, so the boat thinks it is sliding down a hill. And as all these different waves pass under the
boat, they
change the heel angle, requiring some steering adjustments.
We are now trying to maintain the surf (#5) as long as possible. This is often accomplished by spiritual
incantations like cheering, shouting, and stamping your feet so the off-watch gets jealous (and can't sleep!).
Also, watch for cross chop and stray waves. Always be looking for the opportunity to keep the bow lower
than the stern. You can steer around a bump to find a valley. If a large cross wave is coming in from the
side, look for a way to go with it, or an opportunity to step over it, and get it out of
your way.
What do you do when you are just a little bit shy in terms of speed
at the take-off point? There is an advanced skill to develop, called
the "low pole takeoff." This is dangerous, and it can cost you a mast and some sails, but properly executed, it can give
you a short duration turbo-boost, providing a little more speed for the take-off. If you elect to try it, be careful. Let's
start by considering a good old fashioned round down...on starboard pole, a left hand turn until the spinnaker pole goes
in the water and the boom gybes. What a mess! When you are in the middle of your first one of these things your only thoughts
are of survival. But after you've done a few, they can become entertaining. One of the things you may notice is that the
boat is accelerating wildly as it heels more and more to weather, and is going blazingly fast just before the spinnaker pole
hits the water.
In the "low pole takeoff", you use this acceleration to help get that last little bit of speed you need to catch a wave.
The scenario works like this: If you don't quite have enough speed to catch the wave, try bearing off (left turn in our examples)
as part of the takeoff alignment. The boat should speed up, and you are more likely to catch the wave. But remember that
you have initiated a round down. You don't want to take it to its glorious conclusion! Straighten out the boat and get back
to "normal" sailing.
As a driver you MUST know what the apparent wind angle is.
When a boat is sailing "truly fast," you can do things which you wouldn't dream of trying at slower speeds.
You can sail very low, even by the lee; even gybing the mainsail and then gybing it back. You can sail
very high, so high that at lower speeds you might round up. When the water is flowing over the keel and
rudder this fast (typically much faster than the boat designer intended) the boat can become super stable.
This means that when you get the boat really traveling, you have a longer leash as a driver. There are
more directions you can travel. "Truly fast" is easy to say and
hard to achieve, however. To get to "truly fast" you must pass through "dangerously fast." Dangerously fast is when the boat
is the most unpredictable. This is usually in the transition between sailing and surfing, when the boat is under great loads.
At the end of a surf (position #6), for instance, the apparent wind strength is building quickly because the boat is slowing
down. At the same time the rudder is more prone to stalling because the speed of the water flow over the keel and rudder
is slowing. We must keep
the boat carefully aligned at this point.
In summary, we are trying to become aware of how we can anticipate what the boat will be doing next, before
it does it. Angle of heel gives us the most clues so we have time to change what actually does happen next.
If we know what the future will bring we may have enough time to react, and modify the future for our benefit.
This is just another very small
part of the most complex game I know, the game of sailing.
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