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The Sister Ship was found some 70 m to the south of the Punic Ship. Its remains were first revealed in 1973, when the sand bank which moved onto the Punic Ship had in so doing drained from the other wreck. In 1974 when the sand bank retreated from the Punic Ship, the level above the Sister Ship was further reduced.
The Sister Ship’s keel was in two part lying at right angles to each other, suggesting that the ship had received some shock amidships – a shock so violent that it had snapped the keel like a matchstick, crushing togheter the port side ribs. The violence of this impact is incosistent with the natural breaking up of a hull. The crash that sank the Sister Ship was probably also responsible for the immediate burial of her extremities and consequently their preservation. Ramming would explain the sinking.
In a first moment, the Sister Ships seemed to have no ballast. A few large stone were present, but no massive pile such a marked the site of the Punic Ship.The ballast was constituted by chunks of clay. This means that the hull should be well preserved and a microscopic examination of the clay should give a good indication of where it came from.
A hand sounding made on the prow of the Sister Ship in 1974 produced evidence that the wreck was Punic and of the same period of the Punic Ship. Again, it is an Phoenicio-Punic alphabetic sign painted onto the starboard tusk of her ram that proves this. At least, that both ships are of the same period is shown by both set of postsherds.
The structure of the ram was studied underwater, only its starboard tusk having been raised. This ram is an appendage to the ship’s basic structure; it is not an extension of the keel itself. Had it been an extension of the keel the act of ramming would have been equally dangerous to the attacker as it was to the attacked. Like a boar’s tusk, this ram was designated to attack the vulnerable underbelly of a ship. The two tusk-shaped timbers nailed to either side of this keel are made of pine. The wood had been cut across the grain so that the tip would easily snap after piercing an enemy ship. There had been a central timber between the two tusks; though this was missing, a mortise slot in the stempost and the nails in the tusks show that it must have existed.
Thick layers of some woven fabric, liberally smeared with resin, swaddled the entire ram and extended beyond it over the tusks where these were nailed onto the sides of the keel, and even onto the garboards above. The substance which has the consistency of chewing gum, is whitish in colour and retained its elasticity even after drying out in the air. Part of small sheet of bronze with this resin still attached to it was found in the gap between the stempost and the starboard tusk, evidently it had been part of the bronze sheeting that covered the ram .
On the hull itself there is no sign of lead sheating taking over from the ram’s bronze sheating, nor is there any sign of lead elsewhere on the site. The presence of lead is usually apparent, even on the surface level of a wreck, so that though the Sister Ship has not been excavated, it is probable that her hull had never been sheathed.
From the appearance of the ram, it is suggested that the Sister Ship was a kind of liburnian. The rams on all the various forms of liburnia represented on Trajan’s column are the same, and in turn all resemble the form of ram found on the Sister Ship. The Punic Ship may also have been a liburnian, but of a lighter class than the Sister ship which, even from superficial examination appears to have been the heavier vessel.
The Sister Ship differs from the Punic Ship in some structural features too: the greater intervals between ribs (while the widths, 10-12 cm, are the same); the presence of a inner flooring, or ceiling; the presence of notches cut into the group of ribs possibly to hold a rider; a notch cut into the inside face of the keel, maybe connected with the seating of the mast step; the sternpost slightly curved and wider in its inner face. One similarity has already been mentioned: the use of putty on both hulls.