OneSails GBR Racing Spinnakers

The sail that is undergoing the most significant development today is the spinnaker. With the help of better fabrics and ever improving sailmaking technology, spinnakers are more efficient both downwind and also closer to the wind with angles as close as 45° apparent being possible in some cases.

The optimisation of a particular spinnaker or inventory is as much to do with subtleties in shaping as it is for overall area. OneSails make a broad range of high performance spinnakers for racing boats, symmetric and asymmetric and it is important for the owner that every sail is customised for a particular boat with specific angles and windspeeds in mind in order to give truly superior performance.

It wasn’t that long ago that a typical 3 sail spinnaker inventory consisted of a ‘light runner’ (0.5oz), an ‘A/P’ (0.75oz) and a small flat ‘heavy’ (1.5oz). The cloth weights that were used to describe these sails bore little resemblance to the actual weights. Nowadays many more cloth weights are available with perhaps as many as 10 different weights available between 0.4oz and 1.5oz. The cloths are also available in different styles each of which will be more or less appropriate to a given end use.

Towards the end of the 1990’s many boats began replacing their traditional symmetric flat heavy spinnakers with ‘mini reacher’ asymmetrics, more commonly known as A5’s. These quickly developed a reputation as a real utility sail and were able to point higher than the other symmetrics in light airs, were better at beam reaching in moderate airs and could still be flown off a conventional pole as a ‘chicken chute’ in heavier airs. Since then asymmetric development in particular has progressed rapidly and nowadays it is commonplace for most symmetrically rigged boats to also carry an asymmetric or two to cater for particular conditions.

In recent seasons Code Zero’s have become very popular especially on the more modern boats that carry relatively small non-overlapping headsails. These boats are often underpowered in lighter airs and on beam reaches that are too close to fly a conventional chute. Here the Code Zero comes into its own; in very light airs, 4-5 kts TWS for example, a boat with a Code Zero will point virtually as high as a boat with a conventional headsail but with much more area and a far better VMG. As with the A5 mentioned above, the Code Zero is also very useful at broader angles in more moderate airs when the boat would be over pressed when flying a full sized spinnaker.

The graphics below provide an indication as to how various spinnakers might fit into a particular inventory. Bear in mind that these graphics are a guide only but nonetheless provide an indication as to which sails might be used to cover a given range of conditions and angles. Clearly a smaller inventory than those shown would either leave more gaps or else mean that the remaining sails in the inventory are having to do more work or are less than optimal. For example, removing the S1.5 from the symmetric inventory doesn’t necessarily mean that the S2 can’t cover the gap it would leave but it wouldn’t do as good a job. On the other hand, if you want to sail at a TWA of 70° in 4kts TWS your only chance is to fly a Code Zero, the other spinnakers simply won’t get you there! It is also possible of course to have a mixture of symmetrics and asymmetrics onboard in order to cover all the bases. At OneSails our design teams have experience of designing custom sails for boats ranging from America’s Cup to the smallest of One-Designs and it is this breadth of experience that means that we can offer you the right advice and make sure that you get the right sails for your boat and your specific needs. Please don’t hesitate to contact us to discuss all your downwind requirements.

 Spinnaker nomenclature:

Symmetrics

S1 - Light Reacher

S1.5 - Light Runner

S2 - Medium Runner

S4 - Heavy Runner

S6 - Reduced Area Runner

Note: Odd numbers are reachers, even numbers are runners

Asymmetrics

CZ - Tight Reacher

A1 - Light Reacher

A1.5 - Light Runner

A2 - Medium Runner

A3 - Medium Reacher

A4 - Heavy Runner

A5 - Mini (reduced area) Reacher

Code Zero's for racing and cruising

Many modern yachts whether they are designed for racing or cruising tend to be equipped with reduced area or non-overlapping headsails that are very convenient and easy to handle but unfortunately make light air sailing, particularly when just off the breeze very slow and tedious. This is perhaps more of an issue on cruising boats where the single furling headsail will be a lot heavier than the equivalent found on a race boat. 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. A Code Zero (racing) or FFR (cruising) 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.

A Code Zero for racing purposes under IRC has to rate as a spinnaker which places restrictions on the geometry of the sail; essentially its mid with must be wider than 75% of the foot width. This in turn places constraints on how flat the sail can be.

The OneSails FFR (flat furlable reacher) is a cruising version of the Code Zero. Because it isn’t constrained by any racing rules they are actually more efficient at closer angles to the wind than their race oriented cousins.

Both the Code Zero and the FFR are considerably flatter and smaller than their downwind oriented counterparts. The tack of the sail is usually attached to a point just forward of the base of the forestay or perhaps to a short bowsprit or prodder. There is plenty of precedent however, particularly on cruising boats for them to be tacked to a strong point just behind the forestay and set on a short strop so that the sail is set clear of the guardwires.  They are designed to be flown with a taut luff which enables them to be used with a dedicated free flying furling unit which in turn makes them relatively easy to hoist and drop though many racing boats will choose to launch them in the same way as a conventional spinnaker. Both sails are usually constructed from a dedicated ‘Code-Zero’ style laminate though on smaller boats ripstop Nylon is often used as a less price sensitive alternative.

Both the Code Zero and the FFR can be thought of as very versatile sails. Although they are designed primarily as close winded sails they 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 its regular headsail. The difference is that the sail is bigger and lighter so the boat performs better. 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 regular jib but overpowered with a full sized 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.

In summary they are practical, easy to handle sails whose all round versatility makes them a welcome addition to most sail inventories, regardless of the end use, racing or cruising. 

Quotes:

Just a quick note to tell you how pleased I am with the new FFR that you made for Albatross (She 36). It has transformed our light air sailing which was evident with reduced fuel bills on our recent cruise to La Rochelle in hot weather with little wind. It helps that it is so easily handled with the furler so it can be set or furled on a whim. On the leg from Ile d'Yeu to Ile de Re we were getting 7+knots with a 9 knot beam wind - magic - especially as it was faster than the engine would have given us....! (Richard B, Hamble)

The Code Zero was the secret weapon (at Giraglia 2013). It had a much better range than I had expected and was extensively used. So thank you for making it at such short notice....(Mike G, Swan 56)