Photo Credit: @globalsolochallenge
Wind, a sailors’ best friend, pleasant on so many occasions, feared, powerful, and unpredictable in others, is no doubt the greatest ally of any sailing boat. Its absence makes sailors feel frustrated and helpless for lack of progress.
In the case of a race like the Global Solo Challenge skippers will have to sail 26.000 nautical miles at latitudes that span from 43ºN, when they leave A Coruña, to 56ºS, when they reach Cape Horn. It’s clear that skippers will have to navigate their way to find the most favourable winds.
Publications like “pilot charts” and “pilot books” will give them an idea of what they can expect based on their position and the time of year.
Westerly winds
@globalsolochallenge
As a general rule, north and south of 35 degrees, western winds are predominant. These winds are more intense and frequent in the Southern Ocean, where they frequently reach storm force and remain at that intensity for days. On the other hand, in the northern hemisphere, due to the extension continental landmasses, winds from the West are more irregular.
Variable winds
@globalsolochallenge
Between the latitudes of 25 and 35 degrees, known as the “horse latitudes”, there is an area of high pressure in both hemispheres, with light, irregular winds.
Trade winds
@globalsolochallenge
Regular winds, known as trade winds, blow both north and south of the equatorial calms. Usually they are from the north-east in the northern hemisphere and from the south-east in the southern hemisphere. They rarely reach force 7 on the Beaufort scale and typically average at force 4/5 with and good weather, clear skies, clusters of clouds. Atmospheric pressure is very stable. If the barometer suddenly starts to drop, this can be associated with a tropical depression.
ITCZ
@conradcolman
The Intertropical Convergence Zones (ITCZ) or doldrums lies where the trade winds of the northern and southern hemispheres come together. These is an area of low pressure. Winds are light or non-existent, and the weather is warm and muggy, frequently interrupted by heavy showers that bring thunder and lightning and strong or very strong winds from any direction of unpredictable duration. Particularly unpleasant weather that gets even worse when trade winds blow at their strongest intensity. The extension of these areas varies during the year and from year to year.
Cyclonic storms
@globalsolochallenge
Cyclonic storms are the most severe storm systems at sea and are named differently depending on the region where they originate; hurricanes, cyclones, typhoons, and willy willies are all the same phenomenon. Winds blow around a low-pressure area – clockwise in the southern hemisphere and anticlockwise in the northern hemisphere – forming a spiral with winds girating towards the centre. Normally they form at a latitude between 7 and 15 degrees on each side of the equator, but in many cases, these phenomena form much closer to zero degrees latitude.
The majority forms in the ITCZ. In certain barometric pressures, temperatures, and humidity conditions, the whirlpool of air in the centre turns into a severe cyclonic storm where winds can reach up to 200 knots. Initially, in the northern hemisphere, winds move west-north-west and gradually turn north and northeast at higher latitudes. In the southern hemisphere, they start west-southwest and then turn southeast, reaching latitudes up to 20 degrees south. In some cases, in both hemispheres, their path does not change and continue their course west north-west, in the northern hemisphere, and west south-west in the southern hemisphere, until they hit land or gradually lose intensity.
The season of these storms ranges from the end of November to the beginning of June in the northern hemisphere, and from June to November in the southern.
These general weather rules can at times be disproved by local phenomena that have their winds influenced by the proximity to land, the mountains in the region, or other circumstances such as the temperature of the air, the characteristics of the coast, etc. Local winds vary in nature, all countries have their own, and they can be as different and varied as their coastlines. Therefore, these notes are usually more useful when sailing in open waters, when the direction and the intensity of the wind are not affected by the proximity to land and its weather phenomena.
After leaving A Coruña, GSC participants will first sail through an area with variable winds before meeting the northeastern trade winds. They will cross the ITCZ, then the south-eastern trade winds zone followed by another area of variable winds. In the Southern Ocean, leaving all three great capes to port, they will be accompanied by prevailing north westerly and south westerly winds brought by low pressures. Once they reach Cape Horn. Once back in the South Atlantic they will face the same weather patterns found on their southbound route but in reverse.
Understanding and making the most of prevailing winds is part of the GSC.
Participants in the GSC can face extreme weather conditions… winds of different intensity, light, gentle, moderate, strong, very strong, severe, hurricane force, favorable winds, headwinds, and dead calms… They will experience glassy and rippled waters, slight, high, very high, and huge waves… heavy showers, storms, sun, rain, cold, heat and so on… but precisely how much, when, where, and how it will be for them to find out.
