Becalmed in the doldrums

In the afternoon and evening of day 7 of our Atlantic crossing, the wind slowly dropped from a comfortable 12kn to 10kn, then to 8, and then suddenly to 1kn. We had arrived in the doldrums!

This zone, formally called the Intertropical Convergence Zone (ITCZ), is a belt of weather characterised by light winds, sudden squalls and calms that wraps around the globe near the equator and marks the area where the northern and southern hemispheres weather systems abut each other.

It has been infamous among sailors for centuries as an area where boats could be stuck for days, or weeks, becalmed in hot, humid and very still conditions, all the while rolling around with sails flapping and rigging rattling. Aside from driving sailing crews crazy, sitting becalmed in the doldrums could have serious consequences as water and provisions could run dangerously low if the wind took too long to return.

Even though most sailing boats now have an engine, crossing the doldrums still requires careful navigation in order to cross the zone at its narrowest point. One reason is that yachts have a limited supply of fuel onboard, some of which is also needed to anchoring or berthing on arrival at one’s destination. Another reason is that it is good to have enough fuel to avoid squalls.

Why worry about squalls?

Dangerous squalls are a common feature in the doldrums, and in tropical latitudes more generally. They are caused by the formation of tall cumulus clouds which produce sudden and sometimes violent increases in wind speed (sometimes jumping to 40 or 50kts in a matter of seconds) and direction, and are often associated with thunderstorms and heavy rain.

During daylight, the formation and behaviour of these storms can be relatively easily observed and preparations can be made (reducing sail or changing course), but in the dark, even with the assistance of radar, this becomes more difficult. We had had plenty of experience with squalls sailing on the Great Barrier Reef, and more recently in the Mediterranean, and they are certainly things you want to be careful of.

Happily, we ended up only spending 36 hrs in the doldrums, of which we spent 30hrs on engine after the rolling and flapping of Yuma’s sails had begun to drive us nuts after just 6hrs. We had been hoping to experience the glass-out calm conditions so often depicted of the doldrums but instead we got no wind with 1-2m untidy swell which was no fun at all.

And even better, we didn’t encounter any serious squalls even though we saw plenty of very impressive lines and clusters of cumulus clouds, rainbows and some lighting flashes way off in the far distance.