Meteorologists call it the Intertropical Convergence Zone.
Sailors in the Age of Discovery called them the horse latitudes, because, the guess is, that was where they threw livestock overboard from their becalmed vessels to save water.
Everyone else knows them as the doldrums, meaning, according to Webster's, "dullness . . . listlessness or boredom."
For the lone men aboard the 24 sailboats racing to Cape Town on the first leg of the solo around-the-world race, they mean frustration, depression and temper tantrums.
The doldrums lie a few degrees north of the Equator in the Atlantic. They are a band of dirty gray skies, squalls and calms. Flat calms, wherein the boat sits on the water as if on a mirror. The trapped sailor wonders if the wind will ever blow again.
It's hot, humid. And there's the swell. The constant undulation of the ocean that causes the boat to roll back and forth ceaselessly.
As the third week of the BOC Challenge neared its end, the leaders were entering the doldrums at about seven degrees north of the Equator.
Each has studied his weather facsimile reports and the sailing directions for the North Atlantic. Each hopes the band of gray calm will be narrow at the point he has picked to cross into the South Atlantic.
So far, the attention of race observers has been riveted on the leaders.
Guy Bernardin, 42, of France, aboard Biscuits Lu, was in the front--a scant 10 nautical miles closer to Cape Town than Tuna Marine, captained by John Martin, 31, of South Africa.
About 100 miles back, in third-place, Ecureuil d'Aquitaine, was in trouble.
Its Casablanca-born skipper, Titouan Lamazou, 31, told supporters in France by radio that he was holed in the bow in his pre-start collision with Thursday's Child and had been taking water. He fixed the hole with bolts, a piece of aluminum and epoxy.
His major problem now, he reported, was self-steering. His electrical autopilot went out, then his mechanical wind vane steering failed.
These are severe blows for a solo sailor. Without self-steering he must stay on the helm 18 to 20 hours a day and hope he does not fall too far behind the leaders.
You can't keep that up forever. Lamazou is planning a stop for repairs at Ascension Island, 1,500 miles ahead in the South Atlantic.
Others in the fleet are having their problems.
Penti Salmi, 40, of Finland, cleaned up engine-fire damage aboard Colt by Rettig and got his radio back on the air. But he reports self-steering and electricity generating problems.
John Biddlecombe, 42, of Australia, has the worst problem and probably has had the worst string of bad luck of all the racers.
First, he lost a new 60-footer on a reef in the Pacific while doing his race qualifying sail.
With the insurance money, he bought another 60-footer from Claire Marty, of France, when financial problems forced her to withdraw before the start.
He soon discovered the boat, called ACI Crusader, did not have enough ballast to keep it upright in a strong wind.
Two days out he stepped through an open hatch, suffering a severe groin injury that caused him to divert to Bermuda for treatment. He is in Bermuda now waiting to fit a lead bulb, which is being fashioned in Newport, to the keel of his boat.
For him, the first leg is lost. But he reports that he is determined to catch the fleet in Cape Town and do his best for the rest of the 27,000-mile course around the world.