Sentence:  [...] "The High Encounter" entered the <WSD>doldrums</WSD> near the equator, where the ship ended up in the captain's effort to avoid the British. Without wind to move the ship, "The High Encounter" waffled in the slow-moving sea. 
Meaning of the word marked with <WSD> tags:  "Usually preceded by" '''(the)''': a part of the ocean near the equator where calms, squalls, and light, baffling winds are common.