The coming days will be exciting for the latest generation of the Imoca 60. It will be the first time that these flying machines will have to prove themselves in the extremes of the Southern Ocean. Each of the new boats has been designed, tested and built for the Vendée Globe, which will be sailed and possibly decided down here for around 30 days.
But why is the "Grand Sud", as the French call this most open piece of ocean, so extreme? It is due to the lack of land mass in the southern hemisphere. South of the three capes to Antarctica, there is virtually nothing to slow down the wind and waves. When low-pressure systems circle, they are therefore hardly stopped, so that a huge sea can form over thousands of miles. Due to the cold south polar air and the resulting higher air density, gusts also have a stronger effect than in more temperate regions.
Yesterday and during the night, the front of the fleet was overtaken by the front of the first cold front. Charlie Dalin on "Apivia" is still far ahead and may be able to extend his lead a little further, as he can sail with and in the cold front for longer than his pursuers.
As the front passed through, the wind shifted from north-west to west to south-west, so that after a gybe yesterday, the front runners are now sailing on port tack to the east-south-east. However, this is associated with a large swell of four to six metres in height, which has developed with the low pressure. Cross seas form due to the change in wind direction, closer to the Cape of Good Hope also due to the Agulhas Current. This will have to be taken into account when choosing tactics in the coming days, as boats with foils in particular will be strongly affected by the swell.
You have to imagine it as if an aeroplane were experiencing turbulence: It shakes, jerks, falls and rises with the unsteady air currents. It is the same with an Imoca with hydrofoils in waves. With increasing height, the boat crashes more heavily into the seas, as the foils cannot maintain a constant altitude - for this, it would need adjustable horizintal flaps on the rudders, but these are prohibited according to the Imoca class rules.
Life on board becomes really difficult, and even the simplest tasks become a feat of strength because the skippers have to hold on tight at all times to avoid being thrown through the boat. But it's not just about protecting yourself: The boat and its structure also suffer considerably. The forces on the rig and hull increase massively in the waves, which has already led to the first failures and damage. In order to preserve the boat, the sailors have to slow down - not easy when you have competitors nearby and are aiming for a good position or even victory.
The shape of the hull and the hydrofoils also influence how much the swell affects the boat. In the coming days, we should therefore be able to get an idea of which boats are best designed for the conditions in the Southern Ocean. Although months and years have passed to test the Imoca 60, the new designs have never before travelled in the conditions of the Southern Ocean.
The weather forecast looks quite promising for the front runners and fast, which is something they have lacked in this race so far. Four years ago, Alex Thomson set a new record for the route from Les Sables-d'Olonne to the Cape of Good Hope: 17 days and 22 hours. For comparison: Charlie Dalin will need more than three weeks.
However, the leading group will be able to hold on to the low pressure system they are currently in until around Friday and sail with 20 to 30 knots of wind from the south-west. It will be a wet and wild ride with little chance of a break.
What makes these boats and this race so extreme is their relentlessness. The skippers have to deal with the unpleasant conditions 24 hours a day, 7 days a week. When they see a weather forecast like the current one, they will be grateful for the fast conditions on the one hand, but also restrained in their enthusiasm because they know, or at least can guess, how much will be demanded of them.
This is the time when they pray that nothing breaks. Unlike in the first three weeks of the race, when there were always rest periods for necessary repairs, these opportunities will be rarer in the Southern Ocean. There are only a few islands where the sailors could anchor their boats and any stops would certainly be costly in the rankings because the rest of the field is travelling so fast.
Boris Herrmann on his "Seaexplorer - Yacht Club de Monaco" was a good example of this. Before the weekend, one of his halyards jammed and prevented him from recovering the furled gennaker. He knew that the wind would be stronger the next morning. So he took his only opportunity to climb into the mast and repair the lock just after sunset, when it was already getting dark.
The halyard swivel, sometimes also referred to as a "hook", is used to secure the sail head to the mast. Unlike on cruising yachts, the sails on an Imoca 60 do not hang from the halyard; due to the high load, there would otherwise be a risk that the rigging could fray and eventually break over time. There would also be more compression pressure on the mast. For this reason, all sails are attached to halyard swivels, including the main.
The principle of operation of such a halyard latch is as follows: A profile piece is attached to the sail head, which fits into the halyard lock like a key and locks automatically after the sail has been pulled up the halyard. To release the latch, you put slack on the luff, pull the halyard, unlock the latch lock and can then retrieve the sail. Here is a video from Karver on how it works.
However, the mechanism can sometimes jam - which is exactly what happened to Boris Herrmann. The only option then is to climb into the mast and release the hook manually - a difficult manoeuvre, unthinkable in the conditions that now prevail in the Southern Ocean.
After Boris fixed the problem, which cost him a few nautical miles, he is now fighting to catch up with the top boats again. Recently, he was not quite able to keep up with their pace - which is probably also due to his choice of sail for the Southern Ocean. Unlike many other skippers, he opted for a J1.5 or jib top (136 square metres of sail area) instead of an FR0 (fractional code zero with 170 square metres of sail area).
At the weekend, he was probably a little slower in the wind range between 22 and 27 knots because he set less sail area than Sébastien Simon on "Arkéa-Paprec" and Yannick Bestaven on "Maître Coq". With more wind, however, he should have much more control over the boat. Boris' experience shows in moments like these. Having already sailed around the world three times, he knows his own limits well and sticks to them in order to race consistently.
The week promises continued "lively" conditions. In around five days' time, another low will be moving in behind the first one. It is currently quite weak, but it looks like it will intensify just as it approaches the leading group. It could bring storms.
At this point, the leaders will be close to the Antarctic Exclusion Zone (AEZ), which was moved further north by the race committee last week after some icebergs were sighted. This has lengthened the course. It is therefore to be expected that the fleet will remain close to the AEZ - but at the same time keep an eye on the path of the following low pressure system to limit the risks it poses.
