Sailing ships of the 18th century consisted of two distinct parts: the hull and the rigging. The hull, the body of the ship, was constructed of wood. Shipyards began by constructing a frame of huge timbers to give the ship its shape. Planking was then cut and attached, much the same way carpenters attach walls to the frame of a house. Planks, however, were steamed to allow them to fit the curve of the hull. Caulking was used between the planks to make the ship watertight.
Ship builders and crews fought against weeds, barnacles, and marine worms that grew on the wooden hull. Regular scrubbing was needed to remove these creatures, which damaged and slowed the vessel if left to grow. This involved careening the ship by hauling it into shallow waters and onto its side for cleaning and repairs. Shipworm, a sea creature that weakened the hull and caused leaks by devouring holes in the wooden planking, was picked up in warmer waters. To protect against this problem, shipbuilders doubled the hulls by putting on an extra layer of planks that could be replaced again and again. Some builders drove in a layer of copper nails with overlapping heads to create a protective barrier. At the end of the 18th century, ships’ hulls were sheathed in copper below the waterline.
The rigging was the intricate system of masts, ropes, and pulleys that supported the sails. It was common for large 18th-century ships to have three masts: the fore or front-most mast, the main or central mast, and the mizzen or rear mast. The hull could be combined with the rigging in a number of different combinations depending on its shape, where the ship would be sailing, and for what purpose.
The Sutil and the Mexicana of the Galiano expedition were smaller, two-masted vessels known as schooners because of their rigging. Captain Cook’s vessels Resolution and Discovery were originally built as colliers, intended to transport coal along the English coast. They had ample storage space, which made them good candidates to convert for long voyages of exploration. Some nations used naval vessels for their exploration expeditions, such as the swift corvettes Descubierta and Atrevida, which Malaspina sailed for the Spanish.
Expeditionary vessels usually travelled in pairs, so there would be assistance if one of them ran into difficulties. The smaller, lighter ship might do coastal surveys while a larger vessel could carry important stores, trade goods, or weaponry.