Leg 6 is the sprint. After three thousand seven hundred nautical miles of South Atlantic under the keel, NEPTUN turns her bow northwest out of Fortaleza and enters the fastest, shortest chapter of the entire voyage, a 1,747-mile run up the shoulder of South America into the Caribbean. Three days of departure prep on the Praia de Iracema, then the anchor breaks out and the ship falls in with the Corrente Norte do Brasil, the North Brazilian Current, a warm, moving river in the sea that can add two knots of push all on its own. Layer the southeast trades on top of it and the logbook starts filling with 180-mile days almost from the first watch.

The passage itself is the waypoint. Somewhere north of the equator, often before the crew can see it, the sea changes colour. The deep blue of the open Atlantic turns the hue of weak coffee, and stays that way for the better part of a day’s sail. This is the Amazon outflow: six million cubic feet of freshwater per second pushing a plume of silt and floating debris more than 100 miles offshore. You smell it before you fully see it, a green, river-bottom smell in the middle of a saltwater ocean, and for one strange afternoon there are tree branches and water hyacinths drifting past the hull a hundred miles from the nearest shore. Past the plume the coast of Suriname and the Guianas rolls by invisibly to port: a low, dark, rainforest-backed shore that few sailors ever see up close, trailing the smell of woodsmoke on the night watches when the land breeze reaches offshore.

This is classic square-rigger sailing, flying-fish skittering off the bow wave by the dozen, dolphins joining up at dusk, the trades blowing a steady fifteen to twenty from the stern quarter, and the big courses pulling like draft horses. The ship settles into a watch rhythm unlike anything on the voyage so far: no squalls to speak of, no big depressions to read, just hot, open, downwind running. The cook makes more ice tea. The off-watch sleeps on deck. Navigation becomes a game of squeezing the last tenth of a knot out of the set and drift. Twenty sail days pass almost in a dream.

Then the Boca, Trinidad’s Dragon’s Mouth, opens to port, and the Caribbean announces itself the way only Trinidad can: with a wall of sound. Steelpan drifting across the harbour from a panyard rehearsal, soca thudding from a maxi-taxi on the quay, the smell of curry doubles and shark-and-bake from the food carts on Wrightson Road. Port of Spain is not a pretty colonial postcard, it is loud, humid, fiercely alive, and the most richly cultural port in the whole voyage. The Atlantic is behind us; the Caribbean begins here. Two nights ashore and then the ship hauls out for her yard period, antifouling, shafts, the lot, while the crew disappears into rum shops, Angostura tours, and the gravitational pull of a carnival island that never quite stops celebrating.