Mortella III

Country: France

Place: Saint-Florent Bay, Corsica, 38 m south of the Mortella II ballast mound

Type: Round ship; tentatively identified as one of two Genoese merchantmen, the Ferrara or the Boscaina

Identified: Tentatively identified through archival research as one of two Genoese round ships, the Ferrara and Boscaina, wrecked in 1527

Dated: Ceramics of Ligurian manufacture and wrought iron guns suggest the first half of the sixteenth century; dendrochronology of unremoved sapwood layers suggests a felling date between 1517 and 1520; archival research places the loss in 1527

Length Overall: Unknown; the stem itself does not survive, but an estimated rake of 8.6 m was calculated from the hood ends of surviving planking

Number of Masts: At least one; a mainmast step was identified amidships

History of the shipwreck

Interest in mapping the submerged Corsican coastline led France's Department of Subaquatic and Submarine Archaeological Research (Département des Recherches Subaquatiques et Sous-Marines - DRASSM) to collaborate with the Center for Study in Nautical Archaeology (Centre d'Études en Archéologie Nautique - CEAN) on a remote survey in Saint-Florent Bay between 2005 and 2008 (Cazenave de la Roche 2011, 69-71). In October 2005, the CEAN team located a ballast mound dubbed Mortella II, and subsequently found Mortella III 38 m to the south of the ballast mound the following month. Mortella III became an ideal candidate for further investigation, as Mortella II was a smaller mound at a much greater depth (48 m). Preliminary surveys of both wrecks revealed evidence for anchors and wrought iron cannons that suggested a date at the end of the fifteenth or beginning of the sixteenth century.

Full-scale excavations on Mortella III began in 2010 and continued intermittently (2012, 2014, 2015) over the next several years, with the last season concluded in 2019 (Cazenave de la Roche 2018, 89; Cazenave de la Roche et al. 2020, 16). The CEAN team has wrapped up excavations on Mortella III and is now turning its attention to Mortella II (Arnaud Cazenave de la Roche, pers. comm.).

The depth and open position of Saint-Florent Bay protected both ballast mounds over the centuries. Nevertheless, it was clear during the excavations on Mortella III that the ship was stripped before it sank of any artifacts, possessions, or other materials besides its anchors and armaments. The small collection of ceramics recovered from the hull indicated that many of the artifacts were of Ligurian manufacture from the first half of the sixteenth century (Cazenave de la Roche 2016, 856-8). This analysis seems to support the original dating for the wrought iron guns found on the wreck. Geologic studies of the ballast from both Mortella wrecks found that the ships shared a similar source for this material (Cazenave de la Roche 2008, 31). What Mortella III lacked in artifact assemblage, it made up in the amount of preserved hull structure. Dendrochronological samples from different components proposed an origin in northern central Europe (possibly around Burgundy), while the dating from several layers of unremoved sapwood suggests a felling date for the timbers between 1517 and 1520 (Cazenave de la Roche et al. 2012, 75).

Archival work in Spain, France, and Italy focused on documents that might mention ships lost in Saint-Florent Bay in the first half of the sixteenth century. After reviewing several possible identities for the Mortella vessels, the best fit was that of two Genoese ships wrecked in 1527 (Cazenave de la Roche 2018, 282-7). The Italian Wars (1494-1546) at this moment pitted a French coalition called the League of Cognac, which included the Pope, Venice, and the Genoese Admiral Andrea Doria, against the Spanish Imperial forces and their ally, the Genoese Doge Antonietto Adorno (Finlay 2000, 991). Leading the naval forces for the League of Cognac, Doria managed to blockade Genoa from the sea, while allies also began cutting off all land routes. This encirclement caused starvation in the city and led to several merchantmen being sent in search of grain across the Mediterranean.

Two round ships, the Ferrara and Boscaina, were sent to Sicily to obtain grain and were apparently successful in securing supplies before attempting to return to Genoa. Neither ship passed the blockade, and they were chased by French forces into Saint-Florent Bay, where the wind died, stranding both vessels. Instead of engaging with Doria's forces, the crews chose to offload everything they could and abandon the ships before lighting them on fire (Cazenave de la Roche 2018, 286). The few finds recovered from the excavations on Mortella III appear to support this historical narrative, while surviving upper elements from the hull indicate the ship was burning before it sank (Cazenave de la Roche 2016, 859).

Description of the site

Mortella III's remains are covered by two separate ballast mounds close to each other, the longer of which revealed the bottom of the hull, in Saint-Florent Bay, Corsica, 38 m south of the smaller, deeper Mortella II mound (48 m depth).

Cargo

The ship was stripped before it sank of any artifacts, possessions, or other materials besides its anchors and armaments. A small collection of ceramics of Ligurian manufacture from the first half of the sixteenth century was recovered from the hull (Cazenave de la Roche 2016, 856-8). Historical identification suggests the ship had been carrying grain obtained in Sicily during the blockade of Genoa, though this cargo does not survive archaeologically (Cazenave de la Roche 2018, 286).

Hull Remains

Excavation near the endposts and a trench dug amidships provided evidence for two keel timbers, one above the other as the central axial structure.

Keel

Investigators examining the double keel on Mortella III stress that the upper keel is rabbeted throughout and joined to the rider keel beneath (Cazenave de la Roche 2018, 146-54). This arrangement was well-suited for the single-arc hull without a midship flat, which required a significantly thicker keel to provide lateral resistance when sailing and lessen the overall rolling. The rider keel is also much thicker than a false keel, and the bolts driven through it connect the proper keel, frames, and keelson together. This fastening pattern emphasizes that the shipbuilders saw the rider keel as part of the original construction and not a subsequent addition for protection of the main keel (Cazenave de la Roche et al. 2020, 25-8).

No physical evidence of the stem survives (only an estimated 8.6 m rake based on the hood ends of surviving planking), but the forward end of the keel suggests a flat scarf connected these two timbers together (Cazenave de la Roche 2018, 254; Cazenave de la Roche et al. 2013, 24). Amidships, two separate sections of the keel simply butt together, with the rider keel beneath covering the seam. The keel timbers are roughly square throughout until the stern, where they both increase in height (Cazenave de la Roche et al. 2020, 31-2).

Sternpost

Only a small fragment of the sternpost remains; this piece originally butted the keel and extended upward at an angle of 76°. The skeg for this vessel is quite pronounced, as both the keel and rider keel extend beyond the sternpost. Elements from a rudder found just aft of the stern indicate the steering system for the ship (Cazenave de la Roche et al. 2020, 31-2).

A long-armed stern knee was fitted atop the keel and rested against the sternpost. While only the 3-4 m long lower section of the stern knee survives, its forward end appears shaped to butt or flat scarf to a missing additional piece that was part of the deadwood. Shipbuilders filled this void with two timbers, cut to fit over the area at the front end of the stern knee; no further evidence survives to explain whether the original adjacent deadwood timber was removed, the stern knee was a short replacement, or the shipbuilders had inadequate resources and chose to fill the void between two deadwood pieces. The lower face of the first filler timber is cut to match the stern knee scarf, but still left a lower void, while the upper filler timber is on a slope that rebates into the top of the stern knee, increasing the height of the frames in this section slightly before leveling out toward the stern. The rabbet cut into the counter keel rounds upward before the lower sternpost, suggesting that the hood ends fit into the missing section of the stern knee or main sternpost (Cazenave de la Roche et al. 2020, 27-8, fig. 7).

Frames

Framing consisted of floor timbers hook scarfed to overlapping futtocks and secured with two round nails. Along with the hook scarf, several of the floor timbers have an additional recess to fit the shape of the overlapping futtock. The master frame consists of a floor timber with double futtocks attached on each end (Cazenave de la Roche 2018, 225-9). One of its surviving starboard futtocks is attached to the floor timber by a hook scarf with a recess for the wronghead, and the accompanying futtock was a reused timber (there was an unused scarf present on the opposite end). The reuse of the futtock is further demonstrated by a single fastener driven through it, while the other scarfed futtock includes two nails. Only the master frame fastening pattern is horizontal; the others are at an angle, suggesting their floor timber-futtock connections were completed as these pieces were installed. Upper ends of the first futtocks are hook scarfed and recessed to accommodate the overlap of the second futtocks. Most frame elements are relatively square amidships and altered toward the endposts.

Keelson

The keelson is bolted through the floor timbers and keels.

Ceiling, thick stuff and wales

Two recessed bilge stringers on each side of the hull are fastened with round nails that overlay the floor timber and first futtock overlap at the turn of the bilge (Cazenave de la Roche et al. 2013, 28). Another stringer is positioned roughly in the center of the first futtocks, and a final pair of stringers are also present, securing the overlap between the upper frame elements. A single longitudinal ceiling strake was fitted between the dual bilge stringers, while there is a crenulated sill directly above it with filler pieces inserted between futtocks (Cazenave de la Roche et al. 2012, 32). The bottom of the hold was covered with planking laid down transversely, atop the keelson and bilge stringers, creating a flat platform across the hold.

Planking

Planking is thicker (8-10 cm) than seen on smaller vessels, suggesting a large ship capable of longer voyages. Each strake is fastened with two round iron nails per frame station; the nails were driven through each frame and clenched on the inside face (Cazenave de la Roche 2018, 168). No evidence of treenails was identified in the surviving construction.

Mast step

Located amidships, the mainmast step was composed of two long mast partners rebated to fit over the floor timbers and nailed into either side of the keelson. Along the outside upper edge of either mast partner is a rebate with deeper square cuts for the six accompanying buttresses per side. Each buttress was centered above a floor timber when fitted into its mast partner recess, while the outboard end was rebated into the lower bilge stringer (Cazenave de la Roche et al. 2012, 38-9). The upper sections of the rebates were intended to fit the ends of the transverse ceiling in this area, although this ceases past the mainmast, due to the following area being cut off as part of the pump well. Two keys were dovetailed into both mast partners and fastened in place for extra strength. The area between the keys appears to be the mainmast mortise, while toward the bow there is a stanchion and, near the front end of the mast partners, a chock was connected to the top of the keelson. Aft of the mainmast mortise is the pump well, which includes two stanchions positioned atop the keelson and additional stanchions placed over the adjacent frames to create a rectangular box enclosed with several planks (Cazenave de la Roche 2010, 20-4). Toward the stern, another chock was positioned on the keelson, creating the aft end of the mortise.

Deck

The upper sections of the hull did not survive. The first deck is hypothesized as beginning directly above the charred remains of the second futtocks (Cazenave de la Roche 2018, 247-9).

Caulking

Both the inside and outside of the hull were covered in pitch that contained pine resin and animal fat (Cazenave de la Roche 2018, 168).

Ballast

Geologic studies of the ballast from both Mortella wrecks found that the ships shared a similar source for this material (Cazenave de la Roche 2008, 31).

Size and scantlings

Estimated stem rake: 8.6 m. Sternpost angle: 76°. Stern knee (surviving lower section): 3-4 m long. Planking: 8-10 cm thick, fastened with two round iron nails per frame station. Mainmast partners: six buttresses per side.

Wood

Dendrochronological samples from different components proposed an origin in northern central Europe (possibly around Burgundy), with a felling date for the timbers between 1517 and 1520 (Cazenave de la Roche et al. 2012, 75).

References

Cazenave de la Roche, A., 2008.

Cazenave de la Roche, A., 2010.

Cazenave de la Roche, A., 2011.

Cazenave de la Roche, A., 2016.

Cazenave de la Roche, A., 2018.

Cazenave de la Roche, A., et al., 2012.

Cazenave de la Roche, A., et al., 2013.

Cazenave de la Roche, A., et al., 2020.

Finlay, R., 2000.