Sailing with asymmetric spinnakers on sprit boats has become common in the last 10 years but there is a growing trend of using asymmetrics on conventional boats with standard spinnaker poles. While these sails are very efficient they do require somewhat different rigging, and gybing them is quite different.
First let’s look at the different rigging that is required. The biggest differences are that you need a tack line instead of a foreguy on the pole, two afterguys that both go to the tack, and two spinnaker sheets that both attach to the clew. The tack line needs to go through a block right at the headstay or with an oversize pole at the point that is the same distance from the mast as your spinnaker pole length. On smaller boats the tack line attaches directly to the tack of the asymmetric using a snap shackle with a large bale. The two afterguys are snapped on to the bale of the tack shackle. Larger boats often use a large stainless steel ring with bars welded across it in an “X” pattern. The tack line attaches to the bottom section, there are two snap shackles in the top section to attach to the tack of the sail so you can do peels, and the afterguys are attached to the two side sections. Spinnaker sheets should tied to the clew rather than attached with snap shackles; during gybes there is an increased possibility of the shackles coming open as the sail is pulled across the headstay or around the luff, and there is also a much greater possibility of the shackles ripping the sail as they are dragged across it. A “Y” sheet is widely used and consists of two sheets connected with a single short tail that is tied to the sail with a bowline. This reduces the drag during the gybe.
Sailing with an asymmetric on a pole is no different than sailing with a symmetric. You still pull the pole back the same amount and sail the same angles as you do with your symmetric, the sails are just slightly more efficient when sailing deep because they have longer luffs and shorter leeches which gets more sail area out on the weather side of the boat where it does the most good. The downwind asymmetrics, a Code 2A or Code 4A, will generally be maximum size and have a mid-girth that is the maximum for your rating. The shoulders will be just as big as a symmetric. Sailing with the apparent wind forward of the beam, either sailing vmg downwind angles in light air or because a set course requires it, the asymmetrics are noticeably better because of their asymmetric cross-sectional shape. These sails will be built with a mid-girth that is shorter than the foot, be flatter, and have much straighter leech sections. This allows them to be sheeted in tighter without forcing nearly as much wind into the back side of the main and be more open leeched so the power is utilized to make you go forward faster rather than heeling over more.
The major difference in sailing in sailing the asymmetric with a conventional pole is in gybing them. Since you are flying the sail on a spinnaker pole instead of a sprit the pole has to be gybed the same as with a symmetrical. While this is taking place the asymmetric has to be tacked to the bow. The first step is to “Transfer” the tack. This is done by easing the afterguy forward while the tack line is taken up to pull the tack down to the bow. If you are sailing in light or medium air, any time the apparent wind angle is forward of about 135 degrees, you can maintain your sailing angle during this operation. In heavier air when you are sailing deeper you may have to head up some to get to an angle where the sail with still fly when the tack is transferred to the bow.
There are two types of asymmetric gybes, the “Inside Gybe” and the “Outside Gybe”. On boats under 45’ long you can usually do an inside gybe in up to 12 or 15 knots of wind. In over that, or in bigger boats, you will usually set up for an outside gybe. In an inside gybe the lazy spinnaker sheet is led around the headstay but inside of the spinnaker, while in an outside gybe the lazy sheet is led around outside of everything. An inside gybe is faster but an outside gybe is safer, especially in heavy air. In either case you start the same, with the “Transfer”. In an inside gybe you bear away slightly while the transfer is made, making sure to stay high enough that the sail stays full and drawing once the transfer is completed. The old sheet is eased as far as possible as you turn down without letting the sail collapse. As you reach this point the new sheet is hauled in pulling the clew around the forestay and the old sheet is let completely go. DO NOT turn the boat any further downwind until you see the clew is pulled well around the headstay and almost the entire leech is visible on the weather side. At this point you can steer down quickly through the gybe and bring the boat back up to the same apparent wind angle on the new gybe. The crew continues to sheet the sail in on the new side as you steer through the gybe and as you come up to course the sail will fill quickly and pop the rest of the sail around the headstay. Beware…if you turn the boat down too far or too quickly before the clew is pulled well around the headstay you risk getting a wrap in the sail which can take a long time to work back out. As soon as the transfer to the bow is completed both afterguys will be completely loose. This makes it very easy for the bowman to gybe the pole as you are steering through the gybe. You can do either an end-for-end or a dip pole gybe depending on the size of your boat and how you normally do it. By the time you steer though the gybe and the sail fills the bowman should have the old guy out of the pole and the new guy in the pole on the new side. He shouts “made” and the tack line is eased off as the new afterguy is tensioned and the pole brought aft to its proper angle.
In an outside gybe as the transfer is being done you start to turn the boat downwind and the sheet is eased to keep the sail full as long as possible. As you reach the angle where the sail will no longer stay full slow down your turn as the old sheet is released to give the sail a chance to blow out away from the boat. As you reach dead downwind start hauling in the new sheet as fast as possible to drag the clew around the outside of the luff of the sail. Here speed is everything; having several people near the shrouds hauling hand over hand on the new sheet can really help if you don’t have a coffee grinder with two strong guys turning the handles. Once you pass dead downwind turn the boat up faster to reach the angle where the sail will fill. Turning a little faster and a little further than needed will help the sail pop full and get you accelerated back up to your target speed. The pole is gybed from side to side during the gybe just the same as in an inside gybe. As you come out of the gybe the pole is topped back up and the tack line is eased off as the afterguy is brought aft to its proper position.
If you haven’t sailed on a boat with an asymmetric on a pole this all may sound a little complex; but it really isn’t, it’s just different. With a little practice you crew will soon be will be able to gybe the boat just as efficiently as they did before.
This article was written by our frineds at Elliott/Pattison Sailmakers, please keep them in mind if you are ever in the market for sails.