On 8 June 1998, an accident occurred in the port of Barcelona, Spain, involving the MV Gema B, owned by Maritime Gema B SL, during berthing operations. The ship was assisted by the tugs Montjoi, owned by Remolcadores de Barcelona SA, and Pau Casals, owned by Sociedad Anonima de Remolcadores, later Remolques y Servicios Marítimos SL. Due to deficient performance in operation, the cable of tug Montjoi broke, making the MV Gema collide with tug Pau Casal, which was directing the ship by the aft. The Pau Casal could not manoeuvre as its propellor got tangled with the cables of boats docked at the pier and collided with 7 of those boats. The MV Gema, in a manoeuvre to avoid a collision with a big yacht, collided with a pontoon supporting the scaffolding that held the ship Anne Dorothea, under works of reparation by Consorci el Far.

Winterthur Seguros Generales SA, Consorci el Far and the Association Barcelona Fes-te a la Mar (the plaintiffs) claimed for damage resulting from the collision against the shipowner of the ship, its master and pilot, the owners the two tugs involved (the defendants). The defendants appeared in the process and requested the Court to dismiss the claim. The Court of first instance dismissed the claim and released the defendant from liability. The Court stated that there was negligent conduct by the tug Montjoi for the usage of poor equipment. But it also held that there was negligence on the part of the impacted boats and the pontoon, as they were wrongly berthed, lacked licences and authorisations to be docked there, had not notified the authorities to take preventive measures, and its loose cables impeded the Pau Casal from avoiding the collision. The plaintiffs appealed the decision and the decision was affirmed. The Court of Appeal stated that, whether the court applied the wider concept of 'ship', as stated in r 3 of the International Regulations for Preventing Collisions at Sea 1972 (COLREGs), or a stricter concept of vessel which states that for the purpose of collision, the COLREGs only refer to vessels capable of navigating, meaning, with the capacity of movement and manoeuvre, all the vessels involved met that requirement. Therefore, the COLREGs applied to the claim.

The plaintiff recurred this decision in cassation before the Tribunal Supremo/Supreme Court (SC). It alleged an error in the qualification of the accident, because, to be considered a collision, the law required the colliding vessels to have their own governance, and the ships involved lacked that at that specific moment. Furthermore, the liability claimed is that of the owner of the tug Montjoi under the Civil Code and not under the COLREGs, as that tug did not have any direct contact with the damaged property.

Held: The SC affirmed the decision. The SC rejected the argument on the qualification of the accident, as the concept of vessels, for a collision, entails not only those with the capacity to navigate but also moveable floating property on the sea. The law only excludes fixed objects such as piers or rocks. Regarding the argument on the liability of the tug Motjoi to be assigned outside the collision regime, the SC referred to the Convention for the Unification of Certain Rules of Law with respect to Collisions between Vessels 1910 (Collision Convention 1910). Although this Convention had no application to this case, it took as a reference that art 13 did not require direct contact between the vessels as a condition to apply the collision regime.