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The profound calm which only apparently
precedes and prophesies of the storm, is perhaps more awful than the storm
itself' for, indeed, the calm is but the wrapper and envelope of the
storm, and contains it in itself, as the seemingly harmless rifle holds
the fatal powder, and the ball, and the explosion. --
Herman Melville
By heavy weather we mean weather conditions
and high winds which cause a boat and crew to depart from their planned
track and take evasive action to prevent capsizing and loss of the craft.
Needless to say, the best tactic to deal with heavy weather is to avoid it.
Before leaving port always consult the weather forecast. A tight
time commitment to be some where, or to return a charter boat, has to come
second to not going out in dangerous weather. When chartering,
always have a contingency plan for the loss of a day sailing due to the
weather.
The
objective of all heavy weather tactics is to avoid knocking down or
capsizing the boat. A non-breaking wave, no
matter how high, will not capsize a conventional boat with good stability
(1). Breaking waves are the
dangerous waves and can easily capsize a boat if the height of the wave is
equal to or greater than 60% of the length of the boat when hit end on or
much smaller if the breaking wave hits the boat on its side. Boat stability is the
ability of the boat to resist capsizing when hit on its side. It
should be obvious that one of the major goals of heavy weather tactics is
to keep the bow or stern of the boat end-on into the waves. In
doing so, boat stability has only a little impact on surviving the storm.
The main factors are length of the boat, longer is better, and the ability
of the crew to keep the bow or stern positioned into the wind. A
slight increase in wave height can easily overcome boat stability
characteristics. Large breaking waves should be avoided at all cost
and a skilled crew to maneuver the boat under reduced sails or bare poles
is the most important factor to surviving a storm. Thus, active
tactics which allow the crew to maneuver the boat away from large breaking
waves are preferable to passive tactics which invite knockdowns or the
possibility of being capsized. The ability of a boat to upright after
it has capsized is another important characteristic. It can be
estimated by calculating the angle of vanishing stability, or angle of
heel that the boat will still upright itself. For most offshore
boats this angle should be greater than 140 degrees.
Stability Calculator
Angle of Vanishing Stability Calculator
Active Tactics:
The difference between a gale and what has
become know as a "survival" storm is that in the former, with winds of
force 8, or perhaps 9 (say 30 to 45 knots mean velocity), the skipper and
crew retain control and can take measures which they think best, whereas
in a survival gale of force 10 or over, perhaps gusting at hurricane
strength, wind and sea become the masters. -- K. Adlard Coles
If you are able, actively sailing in heavy
weather is preferable to passively riding out the storm. Sailing
also has the advantage of helping you to avoid large breaking waves and
positioning your boat in an area where it can better ride out the storm.
If you are in a coastal area, you may want to approach a windward shore ( a
shore that the wind is blowing from ). In this area,
the waves will be smaller because of the reduced fetch (distance of water
that the wind is blowing over ). Avoid areas where the wind is
blowing against the current, since larger, breaking waves with a more
frequent period will be found in this location. Finally, you may
find a safe harbor to enter but be careful. A wide-mouthed
harbor on the windward shore is ideal. However, a harbor on the
leeward shore with a narrow entrance may be too dangerous to enter.
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Reduce sails or running with bare poles : Reduce the ship's
sails by reefing the main or going to a storm trysail ( a small heavy
weather sail ) and by hoisting a storm jib
( even smaller than a number
4 jib ). If the boat still
has too much sail, consider running with bare poles. "Bare poles"
refers to sailing the craft without sails hoisted. In this
situation, the force of the wind on the hull and rigging generates enough
force to propel the craft.
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Running with the wind and surfing : The first tactic is to
run with the wind. This reduces the force of the apparent wind and
may allow you to navigate the boat away from the path of the storm or into
safer waters. If large waves are present, the boat may begin to surf
down the waves. When this happens, the restrictions of hull speed
are thrown out the window and even a heavy displacement cruiser may
achieve a significant increase in speed. Control of the boat as you
travel down the waves is of utmost importance. Often the boat needs
to navigated down the waves at an angle to prevent slamming into the back
side of the wave in front of you. If this happens, crew can be
injured, the boat may lose its rigging or be pitchpolled. However, by
going down the waves at an angle, you also place your boat at a greater
risk of broaching and capsizing.
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Running warps and use of a drogue : Controlling the boat can be difficult, since waves will often be traveling
faster than the boat and will be breaking over the boat's stern.
This will tend to push the boat sideways creating a danger of broaching (
uncontrolled broadside positioning of the boat in relationship to the
waves )
and capsizing. To help keep the boat on course, you may want to
increase the drag of the water on the stern of the boat. A small
amount of drag will help keep the stern pointing into the oncoming waves
but not enough to appreciably slow the forward motion of the boat. A
small amount of drag can be created by running warps, or loops of lines
secured on the port primary winch, into the water off the stern, then
looping back and secured to the starboard winch. If the boat is
still at risk of broaching, then increase the drag by using a drogue.
This is a small-cone shaped device which is attached to a rode. The
rode is then attached to a bridle ( a line running from one port winch or
cleat, into the water behind the stern and attached to the starboard winch or cleat.) A bridle will
reduce the load on a cleat or winch by distributing the force between both the
port and starboard sides of the boat.
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The
drogue should be set so it is in the wave's trough when the boat is on a
wave's crest. The bridle can also be adjusted to help steer the
boat.
When
too may waves are coming over the stern and
you are unable to control the forward motion of the boat, it is time to
adopt a passive technique.
Passive Tactics:
Being Hove to in a
long gale is the most boring way of being terrified I know. --Donald
Hamilton
Passive techniques involve positioning the
bow of your boat into the wind to help avoid broaching and capsizing.
Unlike active techniques, the boat has no hope of lessening the force of
the storm, or avoiding an approaching large breaking wave which can
pitchpoll (end-over-end capsizing of the boat) the boat .
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 Heaving
To : In this technique, the forward motion of the boat is
slowed, the bow of the boat is turned through the wind but the jib is not
released on the windward side (the jib is backed). The mainsail is
then eased out and the boat is now turned into the wind. The
mainsail is trimmed to help balance the jib, to keep the boat as close to
the wind as possible. Two
opposing forces now exist. The jib pushes the boat away from the
wind but the rudder pushes the boat into the wind. Thus, the boat
comes to a near standstill,
 drifting slowly to leeward.
Click on picture to enlarge
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Use
of a sea anchor off the bow : Sea anchors are essentially
large drogues. Initially, many were made from military parachutes
and are often referred to as parachute anchors. The large size of
the anchor creates a large amount of drag which will significantly slow
the motion of the craft and align the bow directly into the waves.
Unlike a drogue, a sea anchor is always placed off the bow and not the
stern since the bow cuts into the waves and sheds water much better than
the stern of the boat. ( The diameter of the parachute anchor
should be at least 35% of the boat's LOA )
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Hoisting of a small sail at the stern of the boat : On a two
masted boat, a small sail can be hoisted on the aft mast. This sail
can act as a weather vane and help keep the bow pointed into the wind.
On a sloop, a small sail, riding sail, can be set on the backstay.
This technique can be used in conjunction with a sea anchor.
 The
picture on the right shows a riding sail to help keep a boat pointed into
the wind while at anchor. Note the lee boards on the side of this
vessel which project out at a slight angle. This design is
characteristic of wooden boats built in the Netherlands. These
boards or fins (there is one on each side) rotate into the water and
prevent lateral drift of the vessel under the force of the wind.
They function similar to a keel and are designed to be approximately
perpendicular in the water when the boat heels.
-- Click On Picture To Enlarge --
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Lying
a-hull : As a last resort one might elect to go down below and
ride out the storm, letting the boat find its own path in the water.
This almost always exposes the beam of the boat to oncoming waves and
increase the chance of capsizing. Some authors have stated that a
boat lying-a-hull and drifting will have a calming effect on the seas and
prevent waves from breaking. A sinusoidal wave no matter how large
will not capsize a boat. When hit beam on, the breaking wave has
only to be higher than the width of the beam of the boat to capsize the
craft. If you choose to lie a-hull your craft should have a very
high angle of vanishing stability so that it will have a high probability
of righting itself in the event it capsizes. Angle of Vanishing Stability Calculator
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References:
(1) Claughton, Anderw In: Heavy Weather Sailing, 13 Edition,
Editor: Peter Bruce Camden, Maine Chapter II page 11.
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