Navale architecture
The GRAN

 

The study of the Lomellina's architecture constitutes a peak in the long excavation campaign carried out on the wreck, under Eric Rieth's supervision, with the collaboration of Jean-Marie Gassend for on site architectural measurements.

Structural parts of the ship

Due to the strategy adopted for the excavation works (see The Excavation), the study was performed in several stages. The ship's structural parts in particular were studied from the outside of the hull to the inside.

Longitudinal structures

- The whole length of the keel has been preserved, except for a section in its middle, probably torn apart by an anchor. The study of the entire keel is an undeniable asset, not only since it allows us to restore the ship's general characteristics, but also because it helps us understand its shapes, and the principles according to which it was built. The oak keel is 34.18 metres long, 70 cm high on average and about 35 cm wide. It is formed of four elements, the smallest one - back section - being 6.90 m long, and the longest one - front section - approximately 10 m long. Both sections are located at each end of the keel. Their shapes are similar, as they bear the stem and the stern post in the shape of a large fanning branch..

Click on it to enlarge   Exploded axonometrical view of the remains of the keel and rudder.
- Archaeonautica no9, p.24, pic. 7 -


- The stem is still well preserved on a length of 2.25 m and a width of 30 cm.

- All that could be seen of the stern post is its 75° angle with the keel plane. One of the rudder's sections is made up of four poplar pieces laid on a 1.45 m-long oak sole, forming together an angle of 78°.

-Two parts of the girder have been preserved, one at the foot of the mainmast and the other one at the front.

Frame

- Ribbing, made of deciduous oak, was studied at several levels: the lower part, bearing the floor timbers also called “fourcats”due to their fork shape (because of the presence of the careening). These lay directly on top of the keel and form the starting point of the hull, then the joints, followed by the first futtocks (crossing the joints on the orlop deck) and the second futtocks (at main deck level). The frames are of varying width (19-23 cm) and length, possibly in order to use wood in the best possible way (wood could be used over again for other purposes). These various frame elements are joined together by lateral crossing and dovetailed on their contact surface.

Planking and dunnage

- 30 pieces of carvel planking have been preserved.
These are made of coniferous trees (umbrella and Aleppo pine) and of oak at the perpendicular transversal joining with the frame. The planking is 12 cm-wide at the bottom and 10 cm-wide in the upper part, that were maintained except for a 19 cm-wide wale plate. Their width is between 18 and 24cm. the planking is reinforced with lead up to the 26th strake, which is a wale plate. The corresponding lead sheets are on average 120 cm long, 40 cm wide, and 1.5 to 2 mm thick, and are fixed with round headed nails.

- Dunnage is formed of 18 cm wide and 15 cm thick stringers. These are fixed on the inner sides of the frames and distributed by twos at the perpendicular joints of the various frame elements (thus facing the oak planking just described). The oak or beech dunnage is laid flat and continuously without notches on the frames. They are between 13 and 26 cm wide and from 3 to 6 cm thick.

- All the structural elements (planking, frames and dunnage) are joined together by single nailing.

Beams and deck-beams

- Except for the mast step, we found and have studied five beams, fixed at a distance of 2-3 m from each other, and making up the structure of the orlop deck. They are not linked together and therefore do not form a continuous deck. Beams are 20 × 20 cm wide. They are fixed in curves to the ship's sides, and topped by coamings of similar styling. Between beams at the foot of the mainmast are six intermediary 15 × 15 cm. wide deck beams. The resulting surface appears to have been used as a storage space (for guns, spare rigging and anchor).

- The main deck (a continuous deck) is supported by half-beams of uneven width and distance (10-20 cm wide, 10-60 cm apart). The ends of these half-beams are dovetailed onto the top of the clamp. The deck is made up of 10 cm wide strakes laid at a distance of 24 to 31 cm.

Mainmast step

- The mainmast fixing system has been entirely restored despite considerable damage to the starboard side. Four main elements can be observed:

  - The reinforced girder measures 25 cm high and 28 cm wide.

- The two small girders lie on each side of the central girder, and have reconstructed measurements of 5.60 m long, a maximum height of 40 cm, and a width of 27 cm.

- Trapezoid shaped oak cleats embedded forcibly between the small girder and the first stringer to hold the system laterally.

- oak cross girders are embedded or laid on top of the girder, only for supporting the bottom of the hold.
This fixing system can be compared to that of galleys and of some Mediterranean ships like the chebec. It is totally different from systems used on ships of similar size built for navigation on the Atlantic ocean. This type of structure is here observed for the first time; proving that there existed a tradition of construction of the typically Mediterranean round ships, that had gone unnoticed until now. Earlier research in the Genoa archives revealed that the vocabulary used in building contracts for Genoese “naves”was similar to that used for galleys. It can be guessed that the use of one specific term corresponds to a same structure or technique, and therefore to a shared tradition.

Compilation of the mainmast step :

Click on it to enlarge  

 

Basic framework according to the blueprint of galley construction.
- Archaeonautica. n°9, p.70, fig. 33 -


Click on it to enlarge

 

Addition of cross beams supporting the floor of the hold.
- Archaeonautica. no9, p.70, pic. 34 -

Click on it to enlarge   Addition of the floor of the hold and its partitions.
- Archaeonautica. no9, p.71, pic. 35 -

Final reconstruction:

Click on it to enlarge   Compilation of structures
- Drawing by Noël Blotti -

© Max Guérout