Leg 4 begins where Leg 1 ended, at Le Port on the leeward coast of Réunion, the black basalt cliffs still warm behind the ship and the last baguette of the season already a memory. From here NEPTUN points her bowsprit southwest and sets out on the longest single passage of the year after the Bali crossing: twenty-three hundred miles of open Indian Ocean to the tip of Africa. This is blue-water sailing in its purest form, watch-on watch-off under square sail, the swell building out of the Southern Ocean, the air cooling a few degrees with every hundred miles south, and the Southern Cross climbing higher in the sky each night. The ship stands well clear of the African coast and the Agulhas until the weather router finds the window to make her run.

Then comes the seamanship the leg is named for. The Agulhas current boils down the edge of the bank at up to five knots of warm water, and when the southwesterlies sweep up from the Roaring Forties to meet it head-on, the sea does not just get rough, it builds the rogue waves the Cape is famous for, large enough to damage ships far bigger than NEPTUN, and the reason professional weather routing is non-negotiable here. This is the rite of passage that separates blue-water sailors from everybody else, the stretch of ocean where Bartholomew Dias, da Gama and a thousand East Indiamen learned what the Southern Ocean means when it meets Africa’s last stone shoulder. The crew will learn to wait for weather, to pick their windows, and to understand in their bones why the old sailors called this water the Cape of Storms before they ever called it the Cape of Good Hope.

The reward is one of the great landfalls in sailing: Table Mountain filling half the sky, Lion’s Head to starboard, the old Dutch Castle and the V&A Waterfront opening into Table Bay. Cape Town is one of the world’s great cities, Stellenbosch and Franschhoek vineyards an hour inland, Boulders Beach and its African penguins a short drive south, the summer light long and clean and the wines world-class. Leg 4 closes with a short hop up to Saldanha before NEPTUN settles into her thirteen-day Christmas and New Year lay-up at the Waterfront, the season’s only real pause: sails down for maintenance, the rig surveyed from the deck up, the ship quietly catching her breath. Trainees who want to extend their stay are welcome to stay onboard for the layover; everyone else signs off in time for Christmas at home. The promise of Leg 4 is simple and old-fashioned: cross an ocean, round the Cape, and prove yourself against the most storied water on earth.