A perspective on asymmetric spinnakersWed, 14th Apr 2010
By Brad Urie
Asymmetrical spinnakers were once the weapons of only high performance skiffs. However, as with so many other innovations in sailing, they have found their way into the mainstream. J Boats, with their J80, J105 and a number of other models, were one of the forerunners, and were instrumental in bring asymmetricals to a broader group of sailors. Today they are the downwind sail of choice for many, from dedicated racers to cruising families.
Asymmetricals come in a variety of shapes, sizes and designs. It would be impossible to find a consensus as to what the optimal shape or construction would be. The distinguishing feature of every asymmetrical spinnaker however, is that they have a tack and a clew, like a jib. The tack is fixed to the boat and both sheets, port and starboard are attached to the clew. They can be flown without a conventional pole attached to the mast, so that means no jibes on a steep pitching foredeck with a cumbersome pole. If used with a sock, or snuffer, they can be launched and retrieved in a matter of seconds. For those who sail short handed or with a less athletic crew, these are major advantages.
Flatter asymmetricals are at times referred to as gennakers, being a cross between a genoa and a spinnaker.
If the asymmetrical is in a sock, or snuffer, the setup is the same as just described, but the whole sock and sail are hoisted on the spinnaker halyard. Once hoisted, the sock is hoisted and the sock line tied off at the mast. It is best to leave a foot or two of halyard at the top of the sail, so it is not completely hoisted. Otherwise, it is impossible to hoist the sock clear of the head of the sail.
The second is to jibe the asymmetrical the same as any other headsail, but this can be difficult if the tack is not on a bow pole or sprit. The sail must pass through the small space between the luff of the spinnaker and the forestay. If timing is not perfect it can create a mess.
The third option is to jibe the asymmetrical outside of the luff. This requires running the lazy sheet around the outside of the sail before it is hoisted. In this way, the sail passes ahead of the luff during the jib, and the likelihood of a problem is greatly reduced.
Many sailors prefer asymmetricals for the ease of use – no pole, easier to jibe, easy to douse if used with a sock. Their weakness is on deep angles off the wind. Here they are hard to keep filled in the shadow of the mainsail. A bow pole helps immensely to get the sail forward and out of the mainsail’s shadow, but still it is no match for a deep symmetrical spinnaker on a pole.
For this reason, many racers use a pole with an asymmetrical to hold the tack away from the boat on deep downwind angles. This is essentially getting the best of both worlds, but it means having to use a pole again. In spite of that fact, they still retain all the benefits of an asymmetrical sail. A flatter cut will still reach at much higher angles and more easily than a symmetrical. Even if it is used with a pole, it will be easier to jibe than a symmetrical. Ideally, a boat would have a selection of 3 or 4 downwind sails to match a variety of sailing angles and conditions.
Speak to the Ullman sails rep in your area about the downwind sails that are right for you and your boat. We have the experience and technology to maximize your time on the water, whether cruising or racing. Look for Ullman Sails, “An Investment in Performance”
This article was posted on Wed, 14th Apr 2010