The spinnaker sail
Strangely enough, when you sail at a downwind course, the bigger the speed of the boat, the lesser the apparent wind is. At certain point you are left with no alternatives but to increase sail surface, in order to compensate the loss of the wind, otherwise your speed falls. This logic is nothing new, it was known long ago; clipper captains for example staked on studding sails separate from extended yards. Big fishing schooners added gigantic so-called gollywobblers. Modern yachtsmen use spinnakers - big and baggy sails, usually made of nylon, designed to courses from beam reach to a dead run. This sail comes from the original 19th century spin-maker; it is also called colloquially chute (for it resembles a parachute). Not all boats need a spinnaker; additionally not all sailors want to use one. It is mainly a racing sail, used for developing big speeds; it requires particular gear and careful (experienced) handling, in races. It can be your best friend in light breezes, as you will progress even at the weak wind. But it can be your very bad foe in strong weather; because it can become uncontrollable in strong winds. Of course the thing which has the decisive significance is its size. Oftentimes its size is bigger than that of the jib and the mainsail combined. The other important thing is that it has no supporting spar or stay. Even the terminology of this sail is tricky - its parts change their name depending on whether you are on left tack or on right tack.
It is attached to the top of the mast by a swivel. The spinnaker pole is movable; it is attached to the sail by a bowline or snaphook. It has 'head', 'shoulder' and 'foot'. The leeward part is called leech, whereas the windward - luff: these two reverse when the tack changes. The spinnaker is in any way a very special sail. Its success depends very much on the way it is stored, because if you store it improperly, when you unfold it there are going to be snags and twists. Both clews and the head should show out of the bag where you put it in.
You should prepare the spinnaker pole before you pop out the sail. Get it ready by hooking the windward rope (called guy) through the pole. Make sure the pole is completely horizontal, when you attach it to the mast. When the crew is ready to hoist it, the helmsperson gets the boat on a broad reach, so the crew hauls at the halyard. When it is up, a tack should be done. You also have to lower the jib and have somebody keep the spinnaker until you adjust the sails and sheets.
To douse quickly and neatly, work with the jib and steer onto a broad reach. Make sure the halyard, sheet and guy are free, ready to run. Haul the sheet in on the leeward side until you seize the clew, then free the guy and let it loose through the end of the pole. Ease of the halyard as well, pull the sail down, beware for entanglements. Finally let go of the pole by releasing it out of the mast.
Generally, the spinnaker is controlled by its sheet (rope) called the guy and the topping lift (which is used for hauling). The primary control, of course, is the sheet. The guy controls the fore and aft, the leech and luff, the pole as well. The latter should be kept perpendicular to the direction of the wind. The topping lift raises it, it should be kept as high as possible. Spinnakers are suspended by air, they float in the wind; they are very sensitive to the slightest movement in their rigging. They require constant attention, that is why we have noted before that an extra crew person better be assigned with the task to deal with the spinnaker onboard. Coping with this difficult sail is really an art, and you can tell experienced and inspired sailors by just watching them handling the spinnaker.
A well-trimmed spinnaker looks like half a balloon, it flies outside the corpus and it has no ripples on the surface.
The spinnaker has a big effect on steering the whole boat. If it is too light, winds can overwhelm the rudder and cause a broach (inadvertent rounding up into the wind, which is an unpleasant thing to experience, you lose control). If the sheet is loosened to far out, or the pole is too far back, the sail develops an additional sideways force that can lead the boat to windward.
To jibe a spinnaker you shift the pole from one side to the other. This is the most difficult of the jibes, and it requires planning and training. The mainsail and the spinnaker must blow over at exactly the same time.
There are two commands, which the helmsperson says distinctly aloud: "Prepare to jibe!" (you unhook the pole from the mast, take the free end of the sheet).
Then: "Jibe Ho!" - upon this the boat is steered over onto the new tack; the pole is released from the original sheet and taken to the other sheet...
Everything must be under control, because while doing this, you are unstable,
there is also a risk of involuntary jibes, but this will be dealt with in another part.
Learning to deal with a spinnaker is both a skill, an an art.
You need a lot of practice - first in light weather, then in some more difficult conditions; you need intuition, and you need to develop your feeling to the wind.
One thing is for sure: the more you try, the better you will become.
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