Vendée Globe: Higher speeds mean new strategies
by Vendee Globe 31 Oct 2020 00:31 PDT
Thomas Ruyant, LinkedOut © Pierre Bouras / TR Racing
The new generation of IMOCAs are expected to significantly lower the race record for sailing solo non stop around the world, the mark set at the end of the last edition by Armel Le Cléac'h at 74 days 03 hours 35 minutes and 46second, averaging 12.3kts.
Some skippers are talking of a new record of the order of 70 days or a bit less. The performance of these new foiling boats is so much quicker than before, designed especially for this round the world course which is mostly reaching or downwind, usually racing with the true wind direction between 80 degrees and 120 degrees.
Back in 1989 most solo sailors raced with one or even two poles and often with jockey poles as well. Sail inventories were not limited and skippers often carried multiple spinnakers set up in socks. Classical spinnakers and poles have long since been left behind, to the point that this time some will not take a spinnaker (ie with an unsupported luff) of any sort.
Now furling gennakers are so much easier to handle, even if winding them in to gybe is a big physical effort but the possibility of wrapping the sail around the forestay is significantly reduced. Now with only eight sails permitted, the choice of what sails to take is crucial not just to finish the complete course but also to optimise the choices of fastest most efficient angles sailed.
In fact the optimum reaching angles (between something like 70 degrees and 110 degrees of the true wind) are not much different. But the big foiling boats are now doing 30 knots in barely 20 knots of real wind on manageable seas. And making regular 600 mile days or even more (an average of 25 knots), the latest generation IMOCAs will be able to hook into the best weather systems ever more easily.
Deviating above or below the direct course by 10 degrees or even 20 degrees can yield a significant net gain in prolonged high average speeds thanks to two particular parameters which have improved significantly in recent seasons.
First, the autopilots are much better now due to the level of Artificial Intelligence applied, they are much more efficient at learning how the boat should continue to be sailed relative to the optimum wind strength and angles, sea states, boat heel and pitch angles constantly adapting and updating and so gaining in reliability to the point that solo sailors hardly ever steer. (see feature here www.vendeeglobe.org/en/news/19812/autopilots-quietly-revolutionising-solo-racing)
And much more accurate speed polars computer predicted target speeds and angles according to the sailplan - make it possible to optimize the course, now taking into account how and when the sailing conditions will change.
It is the sea state now more than wind strength and direction which dictate the routings, especially for the latest generation of IMOCA foilers. So, for example the routing programme and the interfaced pilot will now work in close harmony to sail a route on which the boat flies for longest at the fastest angles, in moderate waves so the boat does not rise and fall off the foils in the swell.
Likewise, though there are not usually too many spells of upwind sailing, it may be you have to sail further for a favourable shift in the wind but it will often pay now to sail a lower, faster angle. By easing the sheets the IMOCA monohull will accelerate from a typical 12-14kts at 45-50 degrees to the true wind to 17-18 knots or more at 60 degrees. If the breeze is shifting right, for example, it is more efficient to foot off faster and look to get to the shift quicker.
But the biggest gains will surely be in the Southern Ocean where the depressions move at 20-35 knots. Being able to ride at the front of a depression where the seas have not yet built and the wind angles remain favourable has always been the ideal situation for breaking 24 hour records, notably on the entry into the south on the heels of a new depression spiralling off the Brazilian coast for example. This latest generation of fast foilers should, under the right circumstances be able to ride these lows for longer in perfect conditions.
Reaching at 120-130 degrees TWA the acceleration in a low begins in the north-westerly wind which allows the gennaker to be set. But on a conventional daggerboard boat or less efficient foiler when the breeze backs to the westerly sector it become too slow and inefficient to be downwind from 155 degrees -180 degrees of true wind. So it is necessary to luff bringing the course up to the northeast (port tack), or towards the south-east (starboard tack). But now by leaning on the foil downwind at 130 degrees -140 degrees to the true wind, a latest generation IMOCA monohull will still hold high speeds at 150 degrees.
So more often now the skipper will sail more miles but will cover them significantly faster. That will be the key to success on this Vendée Globe knowing when to be aggressive and "attack" on a course which is temporarily less efficient but which yields a longer term gain in terms of optimum sea conditions or long period on a preferred wind angle or to get to a gybe sooner.
The key strategic phases will be during the first week: the exit from the Bay of Biscay, positioning off the Canary Islands for the gybe towards the equator; from the longitude of the Cape of Good Hope to the exit of Cape Horn (southern ocean); off Brazil (negotiation of the Saint Helena anticyclone) and perhaps the last days before the finish, if the northeast wind which is very cold in January, sweeps off the Vendée coast.
So the strategy, that is to say the choice of the trajectory, will depend on the capacities of the boat and the skipper to perform with an optimum angle for their sail and foil combination. It is probably more the state of the sea than the strength of the wind which will influence these options. To "fly", it is better to have 15-20 knots of breeze and maximum two meters of troughs, than 35 knots and five to eight meters of waves. So we will likely see big differences in angles especially after the Canaries, because not only the speed potential of the thirty or so IMOCA monohulls are not the same but now they will more quickly be spread into different weather conditions.
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