Doldrums, pot au noir, ITCZ: what is it like to cross this area?


One thing about the Global Solo Challenge is for sure: both the skippers and the boats will be facing huge challenges during their circumnavigation. Today we will look at the first hurdle the participants will find on their way. This is an area of the world that we can define as being “Between Two Seas”, because of the macro division between global air circulation between the northern and southern hemisphere.

The area where the north-east and the south-east trade winds converge and almost touch is known as the Intertropical Convergence Zone (ITCZ).

Here we will talk about the ITCZ of the Atlantic Ocean, which participants of the GSC will have to cross twice, once on their way out and once on their way back.



From a meteorology point of view, this is a low barometric pressure zone whose specific position is not precisely defined. It extends between the African coast and the South American coast, and changes seasonally. Normally, it is located between a latitude of 8 and 3 degrees north; however, when the trade winds are stronger, between October and December, it extends further. These are the months in which the weather is usually at its worst, because normally the ITCZ is characterised by light winds or long monotonous windless periods, high humidity, and unbearable heat, interrupted by heavy or very heavy storms, accompanied by cumulonimbus clouds. The wind, rain, and lightning can be particularly intense and sudden, varying in duration and direction.



Tactically, as mentioned, it is one of the first challenges that skippers in the GSC will have to face and one of the stages in which we could start seeing different progress among the boats.

One of the first decisions skippers will have to make is where to cross the ITCZ; normally, the narrowest part is between 27 and 30 degrees longitude west.

Sailors will have to be able to cope with multiple adversities but there will be room also for a certain degree of luck, as this is an area in which the weather is very difficult to predict.

The long windless spells and the extreme heat will test the skippers’ morale and spirit, the light winds will test their ability to keep their boat moving.



The rain and storms will challenge their reaction time, often with little time to adapt the boat to the sudden sea and wind conditions that come suddenly and seemingly out of nowhere.

In such unstable and unpredictable conditions, the resting patterns may become a penalising factor for skippers. Overall, this is a complex stage of the circumnavigation, a time when how each one of them copes will depend on many factors, and the design and type of boat, individual ability and, of course, luck, will have an impact on how fast they will be able to cross the ITCZ. All eager, presumably, to reach the south-east trade winds and enjoy more stable conditions.

Thanks to its long reputation, the ITCZ is known by many different names (still used today) such as pot au noir, doldrums… all associated with different stories that have taken place in this area and all have in common the long absence of wind that can leave boats stranded for days or even weeks, and the violence and strength of its storms.

So, yes, the ITCZ will indeed be one of the many challenges Global Solo Challenge participants and their boats will have to face during their journey alone around the world.