The shipwrights of Albaola are currently building the structure of the lower deck of the San Juan. This is the first and lowest of the ship's three decks and is located approximately 2.2m above the keel.
The structure of the deck consists of a series of longitudinal and traverse members, the first of which are the shelf clamps. These are thick planks that run longitudinally along the inside of the ship’s frames. These planks are nailed to the frames at a slightly higher elevation fore and aft of midship, thus creating the curvature or sheer of the deck.
More pictures of building process here