Georges,
Normally a gennaker in a sock is a pretty simple sail to hoist, fly and control. The normal (I say “normal” as each
sailmaker has a slightly different layout) configuration at the head is a D ring or O ring, onto which you clip your spinnaker halyard snap shackle. Lately I have seen
sails out of the North and other lofts with no s/s ring – simply a looped strop through which the snap shackle is clipped. From there the sail is attached via a short strop with the sock control line lead through a block which is also at the head of the sail. All you have to check is that the sail head and/or the control line is not twisted in this area as it will make raising the sock or snuffing it very difficult.
There are a number of ways that the tack of the sail is attached to the
boat – the easiest is to have a fixed line which can be tripped but some folk use a down-haul configuration via a set of blocks and when sailing on cats, I use a line attached to a pad-eye on the bow, taken up through the tack ring and down to the bow pad-eye and then onto a cleat. Whichever way you tack the sail, just make sure that you secure the end of the line but have no
knot in it as you need to let the tack fly when dousing the sail with the sock (snuffing it). Once you have the halyard clipped on, the tack set up and your sheet lead aft via a spinnaker block and then lead to a
winch, have the person at the
mast hoist the sail in the sock, ensuring that your sock control line is secured so that the sock will not fly up uncontrolled. When all is hoisted and you have the halyard locked off, show the sheet
winch person you are ready to launch the sail and under control start pulling the sock up. As the
wind catches the sail it will start to billow and two things need to happen simultaneously – the sheet needs to be taken in slowly and you need to control the sock line so that the “hoop” does not shoot up as the sail billows. It is advisable that the person controlling the sock line wears gloves to prevent rope burn!
If the line is not controlled, you find the line sometimes bunches up inside the sock and you cannot get hold of it to be able to douse the sail later and, if it shoots up too fast, it creates friction burn on the
fabric of the sail, lessening the life of the sail.
To douse or snuff the sail, the normal method is to let the tack fly whilst the sock is being brought down. As the sock reaches about half way down, then let the sheet loose a bit so that you can snuff the sail completely – never let the sheet completely free. The sock on a gennaker should come down to about a metre from the bottom of the bunched up sail so that the tack and clew are exposed for attaching the tack line and sheet.
It is a great sail to use but needs to be looked after. Snuff and drop it early if the wind starts picking up. If the wind is too light to use the sail, don’t put it up as it may well flog itself to death. Do not leave it on
deck if not being used – the sun kills the fabric! If used on a
catamaran, be careful not to hoist it if there is not enough wind as the action of a
catamaran mast is totally different than that of a
monohull – the cat mast rocks side to side very quickly when the wind is light and causes the sail to whip and then rip.
Getting back to the snap shackle on the spinnaker halyard, make sure you buy a really good quality one and maybe a size larger than you actually need. I have seen a number of the good looking but bad quality ones distort and, even themselves or the locking pin, break under load, resulting in the
boat sailing over the gennaker – an expensive exercise!
John