Rigging Your Asymmetrical Spinnaker
by Sandy Goodall
Your new asymmetrical spinnaker (aspin) has just arrived in a box delivered by UPS. In all probability, your sailmaker installed the new aspin in the snuffer you so wisely ordered, and the whole unit is ready to hoist.
Well hold on, there are a couple of things to rig first.
Once down on your boat, dump the sail, in its bag (often called a spinnaker "turtle"), on the foredeck, while you rig a few necessary lines. You'll need at least one, if not two sheets — each about twice the length of your boat. Choose a line that is comfortable in the hand, and thick enough that 1) you can get a good grip, and 2) it will have enough friction on the sheet winch. Not too thick, though, because you want your new sail to be able to lift and fill in light breezes too. So choose a sheet that doesn't absorb water.
Tie the sheet(s) into the clew of the sail. With the sail already installed in the snuffer, you'll easily identify the top of the whole unit, with the clearly marked tack and clew hanging out of the "mouth" of the snuffer.
If you choose to use two sheets, you will be able to jibe the sail just as you would a headsail — by easing one sheet and trimming the other, as you steer the boat through the turn. Some sailors choose to use only one sheet and when jibing, they snuff the sail, then go forward and walk the single sheet around the forestay, lead it back through the sheet block on the new leeward side, then un-snuff the sail again. Perhaps that's okay if you’re on a long ocean leg, and will only jibe once in a long while and in light breezes. Personally, I prefer using two sheets, and having them both led through their own sheet blocks on either side of the boat.
You'll also need a "tack line". This can be about the same diameter as your sheet(s), and should be long enough to be led from the tack of the sail, through a block as far forward on the bow as you can get it, and then back to the cockpit somewhere, with enough purchase that you can adjust it under load.
We want to fly the tack of the sail from a point as far forward as possible, to create some useful separation from the rest of the rig. In some cases, that will be out on a bowsprit. In that instance, or if you have a bow pulpit that is aft of that point, be sure to lead your tack line from the tack of the sail, over and outboard of everything, before leading it through the tack block and aft. It helps when rigging spinnaker lines to imagine the sail in its “flying state” and envision where the lines from tack and clew would have to lead to prevent tangling.
Tie the tack line into the tack of the sail. Lead it to one side or the other of the forestay, down through the tack block and then back along the deck to the cockpit.
Things will be simplest of you plan to hoist the sail on the same side of the forestay as you led the tack line. Tie off the tackline with enough slack that the tack of the aspin will be able to fly several feet above the bow.
Now locate your spinnaker halyard, and tie it into the top of the sail. If you have more than one spinnaker halyard, then choose the one on the same side of the boat as you led the tackline. Look aloft and make sure that the halyard is not twisted around the forestay, on its way down to the head of the sail.
Okay, you’re making progress. Now, lead your sheets back to their respective sheet blocks, which should be well aft towards the stern — just as you would have normal sheets for a symmetrical spinnaker. Make sure both sheets are outboard of everything. Obviously, one sheet will lead aft from the clew, while the other will have to start by going forward, around the forestay, before going aft to its sheet block on the other side of the boat.
Here's where you can begin to tangle things if you don't do this right. Choose the (active) sheet that will be on the same side of the forestay as your tackline. Lead that sheet from the sail’s clew (still in a pile on the foredeck) outboard of the shrouds, over and outside the lifelines, back to its sheet block, in through it (from the outside), and then forward to the winch you will be using.
Now you have to choose how to lead your second (lazy) sheet. It can either be led under the tackline, around the forestay and down the other side of the boat—or OVER the tackline, around the forestay and down the other side of the boat. Doesn't sound like a big difference, does it? It's not, but in the first case, the second sheet will be "inside the sail", once it’s flying — between the rest of the sail and the forestay— while in the second case, the second sheet will be hanging "outside the flying sail", the tackline, and the forestay. The difference here determines how the sail and its sheets will be jibed, when the time comes. There are pluses and minuses to both systems.
With the lazy sheet led “inside” the sail, you will have to drag the sail through the relatively narrow gap between the sail’s luff, and the forestay. This can take a bit of practice and good timing, when easing and trimming. However, the lazy sheet is over and aft of the tackline, which means you can’t sail over it!
With the lazy sheet led outside of the sail, your technique during a jibe is a bit different. In this case, once aimed dead downwind, you ease the sheet completely, so the sail is flying like a flag, straight downwind. Then just complete your turn and trim in on the new sheet. Sounds simple doesn’t it? It is — as long as you managed to do it without sailing over the slack lazy sheet, and getting it hooked under the boat.
The choice is yours, but I prefer the “inside” system.
About the Author: Sandy Goodall, FX Sails Head of Design, has 30 years sailmaking experience and is the former technical director and head of design for Elvström Sails Denmark.