Pasaia (Basque Country)

The keel

The building of the San Juan has already started in Albaola the Sea Factory of the Basques- the keel has been laid. The keel is usually the longest timber in the hull of a ship.  It is the base on which all the remaining structure rests. In the case of the San Juan, it's 14,20 m long.  The original tree trunk weighed 8 tons before being shaped.

quilla nao san juan museum

Laying the keel of any ship is always a turning point, and so it is with the San Juan. It's not really the beginning of the construction, as some important steps have already been taken, but now we feel as if the ship is starting to materialize before our eyes.  From now on it will be easier to imagine how the construction process will go.

quilla nao san juan museum

The unusual shape of the keel

The morphology of the keel of the San Juan is one of her most striking features. In most ships, the keel is just a long, rectangular-sectioned beam. However, in the San Juan the keel makes you think of a dugout canoe.  It has a T shaped middle section that becomes a Y shape towards the ends. This diminishing angle of the top of the keel matches exactly the underwater shape of the ship.  The shipbuilders that carved the original keel five centuries ago were very skilful, and they knew in detail the exact shape and volumes the San Juan should have.

quilla nao san juan museum

This way of shaping the keel is a throwback to a medieval technological tradition that was disappearing by the time of the San Juan in favor of easier methods.


The keel of the San Juan was made out of beechwood, which is another source of astonishment to the experts, as all the rest of the structure of the ship was oak. The use of beechwood in shipbuilding has been very infrequent, as it rots easily when it is subject to a 'wet-dry' environment. However, the keel was always under water, not only outside, but also inside, in the bilge, as there is always a little water that the bilgepump can't manage to suck out. Beechwood can last under water for centuries, as the keel of the original San Juan demonstrated when found in Canada.

Other historical wrecks of Basque boats share this feature with the San Juan, such as the medieval wreck found in Urbieta, Gernika, or the Newport wreck in Wales. It seems that a beechwood keel was a feature once common to many Basque ships.

quilla nao san juan museum

More pictures of building process here