Home » Sail » Guide to Sail Trim Part III: Symmetric and Asymmetric Spinnaker Trim

Guide to Sail Trim Part III: Symmetric and Asymmetric Spinnaker Trim

This final part of this sail trim series could be a book in itself. However here I will be brief and try to cover the points often raised by my customers. I realise a lot of you may never use the spinnaker or gennaker that you have aboard or may not even have one. Last week, I was sailing on a three year old 130 footer in the Rhodes and after checking the foresails aboard which we supplied the skipper asked if we could hoist the asymmetric. The crew being few in numbers had never hoisted the sail. After working out where to run the leads, etc., we sailed off in the sunset towards Turkey.

Here we will consider cruising Symmetric and Asymmetric all purpose Spinnakers. For the French reader a Gennaker is only a code 0 type sail and not the Anglo Saxon general Asymmetric.

For most of us the power of our downwind sail is proportional to the surface presented to the wind. Therefore we generally need to hoist the spinnaker fully and to lower the pole, if used, as much as possible. On a long leg the halyard should be moved from time to time to avoid point chafe and periodically checked.  After hoisting the pole will be pulled back so that it is approximately perpendicular to the wind. The sail should be sheeted so that the luff is just stable for cruising. If the foot is tight on the forestay, ease the guy a little to move the pole forward. If you are concerned that the boat will roll then use barbers that pull the sheet and guy down and forwards.

Before setting the barber you can adjust the pole height on the mast if this is possible by setting the pole horizontal and at the same height as the clew. With barbers on, adjust their height so that the clews and pole are all basically the same height. Another rough guide is if the spinnaker luff begins to curl in the head the pole is too low and obviously if it curls low down in the luff then the pole is too high. To move the pole the downhaul will need to be adjusted to keep the pole stable.

More often than not spinnakers symmetrical and asymmetrical alike tend to be over sheeted rather than under sheeted. Sheet in so that the sail fills and is stable, then ease until the luff starts to curl in. As soon as this happens stop easing and sheet back in a few inches.

If, when luffing with the sail, you start to need to sheet the traveller in a little, you will probably be better and more comfortable with the genoas. If you broach with the sail, ease the sheet rapidly and if really needed, ease the halyard a meter or so if you can’t sit the boat back up right. Bare away to rejoin your course and then sheet in again.

Most cruising downwind sails are set with snuffers. Most modern twin sleeve snuffers and single sleeve snuffers, but with an external hoist halyard, work well. Care must be taken that the sock does not twist when hoisting, and good swivels help here. Additionally and especially with an asymmetric, the tack and clew should be free of the snuffer when the sail is hoisted.

Gybing an asymmetric is relatively easy and is one of the advantages of this sail. If flown on a pole, the tack should have a downhaul to the bow as well as a guy. The sail should be established on the bow with the downhaul and the pole stocked. The question then is whether to gybe the sail on the outside or inside. Some rigs are such that there is never enough space inside. If you have the choice then I think the test is when you let fly the sheet, if the clew passes forward in front of the luff, then gybe outside—this happens in about 15kts true on a typical boat. If the wind is light and there’s space, then set for an inside gybe. A Gybulator which is a short batten at the tack of the asymmetric is now fairly standard and avoids the lazy sheet dropping down over the bow or pole when gybing the sail on the outside.

If you are short handed and certainly if you have a symmetrical sail then perhaps it is best to snuff the sail before gybing using the space behind the mainsail where there is less wind.

Sailing these days on a ketch there is often a wonderful choice of downwind sails to choose from. On a reach the mizzen mast allows a mizzen staysail which has an important effect on performance. Besides being a great sail to have it is comfortable to use as it sets amidships. The only advice I often give to my customers here is—in order to gain separation, tack the sail to windward perhaps off the genoa’s car, and sheet to leeward off the mizzen boom.

Though basic, the ideas developed in this short series of articles I hope have been of some use to either you or crew you may invite aboard.  If this is the first you have read, the previous articles on Foresail Trim and Mainsail Trim are available on the All At Sea web page:  www.allatsea.net.

Andrew Dove is Area Manager for North Sails Caraibes, based in Guadeloupe.

For a number of years we have used in Guadeloupe a brief guide to Sail Control I had the pleasure to develop with North Sails France over ten years ago. This is a free handout, in French that is available in our loft. A good number of our customers use this to train crew and friends. The following is the third part of a short series of articles based on this hand out. This will not make you ready to sail the Americas Cup, and has no pretension to be complete but do enjoy and use these articles with those around you that are learning. Please email andrew@sales.northsails.com with any questions. My staff and I are here at your service.

Guide to Sail Control

Caribbean renowned sailing expert Andrew Dove of North Sails Caribbean shares some of his secrets on sail Trim. Here is a quick lesson on “how to sail.”

” For a number of years we have used in Guadeloupe a brief Guide to Sail Control I developed for North Sails France over ten years ago. This is a free handout, in French, and a good number of our customers use it to train crew and friends. The following is the beginning of a short series of articles based on this hand out. It will not make you ready to sail the Americas Cup, and has no pretension to be complete, but do enjoy and use these articles with those around you that are learning. Please email andrew@sales.northsails.com with any questions.”

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