The Ventura do Mar, a 50-foot, two-masted ketch built in the 1950s, cuts through the Atlantic en route from Funchal to the Desertas, three uninhabited islands 21 nautical miles to the south-east of Madeira.

On board, a small group of birdwatchers from Norway, Britain and Portugal prepare their telescopes and binoculars to observe the seabirds found on the islands, including Zino’s petrel, Cory’s shearwater and the Madeiran storm petrel.