The sail wardrobe of the Imocas is one of the main factors determining the success of the Imoca teams in The Ocean Race Europe. According to the class rules, a maximum of eight sails may be on board, one of which must be the storm jib, which is mandatory. If a sail is damaged, it may be repaired by a sailmaker authorised for the race. However, the cut, profile and dimensions must remain unchanged.
To a certain extent, four sails are essential basic equipment for every boat when it is on course: the main, the J2 working jib, the J3 heavy weather jib and the J4 storm jib.
That leaves four sails that can be set for rougher courses or light winds: This is the segment in which the sail plans differ the most, and the exact dimensions and specifications are guarded like state secrets.
In fact, well-funded teams develop a much broader portfolio of sails in order to gradually find the best setup. The gallery above shows an example of what such a setup might look like.
The mainsail - the main engine with four-speed gearbox
A lot has changed in mainsail design in recent years. Because the foils, and with them the speed potential, have become ever greater, the surface area in the top has become significantly smaller. In contrast to earlier cloths measuring around 180 square metres, the current Imocas only have around 170 square metres in the main, which not only reduces drag, but also pushes the reefing limit upwards. This in turn helps to reduce unwanted turbulence behind the free-standing masthead when reefed.
While older boats in this class had up to four reefs, today three are sufficient. This means that there are four performance levels for the main: unreefed, reef 1, 2 and 3, each of which can be combined with different headsail configurations. In stormy weather, the crews take the main down completely in case of doubt and only sail with the J4 - but only in winds of 50 knots or more.
J0 - the latest addition to the Imoca class
If you like, the J0 (pronounced: tschej si:ro) used on the Topp halyard is a kind of Genoa 1 of modern times. The membrane sail, which is around 135 square metres in size and has a relatively flat cut, is used in light winds; however, it can also provide propulsion on rougher courses in winds of more than 20 knots - for example, if the code zero is too large or if the top halyard is broken.
Some Imocas moor the J0 at the bow; however, more and more teams do without their own jib, which is why the J Zero is then sailed on the aft furler on the bowsprit.
J2 - the Swiss Army Knife under the headsails
Almost as indispensable as the main is the J2, which can be called a working jib with a clear conscience. It is used on a structural forestay, so called because it holds the mast and cannot be removed - unlike all other stays in the bow area.
Strictly speaking, the J2 is actually a G2. This is because the "J" stands for "jib" and refers to a jib. However, the J2 is a headsail that overlaps the mast and is therefore, unlike the J3 and J4, a genoa. However, for the sake of simplicity, riggers and sailmakers stick to the same nomenclature, which is why we do the same.
The J2 works in a variety of configurations and on different courses. Downwind, it is the sail of choice up to around 18 knots true wind speed; however, it can also be used very efficiently on half-wind and room-sheet courses in 25 to 30 knots of wind, especially as the new foilers require less surface area and pressure than more conventional Imocas anyway. The J2 measures around 95 to 100 square metres and is now cut as low as possible to the deck to prevent pressure equalisation between the windward and leeward sides. The lower leech only rises towards the leech because otherwise it would come into contact with the outriggers of the wing mast.
However, it has one disadvantage: if it tears or punctures, it cannot simply be rolled up and taken down like the J3, which is also possible in strong winds. Repairs are therefore usually carried out with the sail upright. However, this must be dry and as salt-free as possible.
J3 - the not-so-little sister of the J 2
If the J2 is too big or broken, the crews quickly switch to the heavy weather jib. This is used on a removable stay to make tacking or jibing with the J2 easier. It only measures around half the area of its big sister, i.e. around 50 square metres. Because it is cut even flatter than the J2 and produces less drag, the most efficient foilers sail with the J3 from 20 knots in windswept upwind or reaching courses.
Even in light and medium winds, it still plays an important role on such courses: it helps to bridge the gap between the spinnaker or code. As a so-called double header, the configuration has become indispensable in the Imoca class, especially in The Ocean Race, because unlike in solo regattas, more hands are available here to get the last out of the boats in full regalia.
J4 - the compulsory sail that no skipper actually wants to set
The storm jib is a robust, comparatively tiny triangle of canvas designed to take the worst knocks in extreme wind conditions. Boats may find themselves sailing with just the storm jib in apocalyptic conditions that they would rather not experience.
When it is often said that only eight sails are allowed for the entire duration of The Ocean Race Europe, then the J4 falls by the wayside. You can do it that way, but it is misleading. Just because the sail is mandatory does not mean that it should be omitted.
A2 - the "Big Blooper" of the Imocas
The only space windsail that is not used on a furler is the "Topp-Spi" or "Spi Max", more correctly referred to as A2. "A" stands for asymmetrical, the 2 for a particularly bulbous cut optimised for deep courses with relatively broad shoulders. It can measure up to 400 square metres and is relatively unpopular with solo skippers on the Vendée because it can only be jibed or recovered with risk in fast freshening winds. To make it manageable at all, it is sailed in a recovery tube.
Code Zero - the flat giant
For many owners of cruising yachts, the Code Zero has become a favourite additional sail - often the only one apart from the main and genoa. This is because it is easy to furl and can be used both for upwind courses in light winds as well as for rough courses in strong winds.
This applies to the Imocas in a similar way, although the Code Zero is more of a specialist than an all-rounder. It is used on the top halyard, has a surface area of around 300 square metres and is made of a high-strength membrane, which makes it very heavy - a good 80 kilos. When rolled up, sailors sometimes call it the "Anaconda" because they have to heave it on deck when recovering, as if it had a life of its own. And it does when the wind and swell cause it to sway.
Code 3 - the heavy weather spy
Smaller and flatter than the A2, but rounder than the Code Zero - that's the Code 3, which used to be called the A3. But it has in fact become flatter in the meantime due to the increasingly forward apparent wind that the current foilers produce at full speed and therefore justifies the change from "A" to "C".
Measures between 220 and 250 square metres, is driven on a fractional halyard and can be rolled away for recovery, which makes it much more manoeuvrable than the A2.
FR0 - the little brother of code 0
Counts in the strong wind wardrobe. Not too far removed from a J0, which is smaller, and the C0, which is significantly larger. The reaching sail for medium winds - and more than that.
As a fractional zero, the FRO (pronounced "Frouw") is set on the fractional halyard and always travelled on a furling system on the bowsprit. If the A3 leaves the mooring lines or goes overboard, it can take over its function on room sheet courses in strong winds.
The details of each sail inventory remain secret
So much for the most important and most common sails of an Imoca today. You have to think of it like a multiple gear shift, because the main with its three reefs and the partly complementary headsails can be combined into 20 sensible sail plans. In fact, working out the best set-up is an enormously important lever in optimising the boats for the respective race, as well as in this article can be read. In addition, the foils can be varied in terms of their angle of attack and the degree to which they are extended
Jochen Rieker
Herausgeber YACHT