Thursday, 6 February 2014

Asymmetric Spinnakers for Cruising

Anybody that is thinking of buying an asymmetric spinnaker for cruising will be looking for a sail that is easy to deploy and which is easy to manage when flying. However, all asymmetrics are not created equal so some thought needs to be given as to exactly how the sail will be used. A sail that is designed to be used as a downwind sail will be very different to a sail that is designed primarily for close reaching. Neither will fulfill both roles particularly well so compromises may have to be made. OneSails have a dedicated range of cruising asymmetrics to suit every end use and which are designed with ease of use and practicality in mind.

FFR – flat furlable reacher
Modern cruising yachts tend to be equipped with reduced area genoas that are very convenient and easy to handle but unfortunately make light air sailing, particularly when just off the breeze very slow and tedious. Even in more traditional boats with large overlapping genoas the sails tend to be so heavy that in light airs they just sag and do very little. The FFR is the ideal solution for the discerning sailor who wants to maximise the yachts potential in light airs and have more control at wider angles as the breeze builds.

These sails are considerably flatter and smaller than their downwind oriented counterparts and are designed to have a taut luff that enables them to be used with a dedicated free flying furling unit which makes them relatively easy to hoist and drop. The FFR is constructed either from Nylon (on smaller boats) or a dedicated ‘Code-Zero’ style laminate on larger boats. They are practical, easy to handle sails that don’t take up too much space and as such are ideal for yachts where space and manpower are often at a premium.

The FFR is a very versatile sail. Although it is designed primarily as a close winded sail it can be used in other ways too. In less than around 5 knots TWS it is possible to sail as close as 50 degrees TWA which is pretty well as close as the boat would sail with it’s regular furling headsail. The difference is that the sail is bigger and lighter. As the breeze builds the sail is used at wider angles as the luff begins to sag and the boat starts to get powered up. In 10 knots TWS the sail would typically be used on a beam reach when the boat would be underpowered with the furling jib but overpowered with a regular spinnaker. The same principles apply as the breeze builds further; the sail gets used at wider angles down to a maximum TWA of around 130 degrees but by this time a dedicated downwind oriented sail would probably be more stable.

Midi & Maxi Cruising Asymmetrics
OneSails cruising asymmetrics take full advantage of the technical advances made in recent years in the three dimensional shaping of downwind sails with the lessons learned resulting in versatile and stable sails aimed specifically at the cruising sailor. The ‘Maxi’ sail is as large a sail as we would recommend for a cruising application and is designed in a way that maximises its ability to help the boat get downwind. In perfect conditions it would be possible to get as deep as 160 degrees TWA though by this stage the sail would be on the verge of becoming unstable and 140 -150 TWA is therefore more like the norm.

The ‘Midi’ sail is slightly smaller and is regarded as the ‘all-purpose’ sail. It is a better reaching sail than the ‘Maxi’ though wouldn’t ultimately get as deep. This sail would typically be used between approximately 90 and 150 degrees TWA though as with the other sail options this will depend on the sheeting angle and the particular characteristics of the boat. Handling of the ‘Maxi’ and ‘Midi’ asymmetrics can be facilitated with the use of a snuffer or a ‘top-down’ furler that is designed specifically to furl this type of sail.

At OneSails we will of course be more than happy to advise on what the best solution is for a particular boat or the way in which the owners are anticipating using it. Whether you are doing day sailing around the estuary or have an ARC passage in mind we have the right product for you.

No comments:

Post a comment