Adriática SA de Seguros (the plaintiff) claimed for damage to the Spanish-flagged MV Monte Furado, against Flota Cubana de Pesca (the defendant), the owner of the Cuban-flagged MV Rio Contramaestre. These fishing vessels were involved in a collision that occurred off the coast of Namibia. The defendant filed a counterclaim for the damage suffered by its vessel from the collision. Minerva SA Compañía Española de Seguros Generales (Minerva), the insurer of the MV Monte Furado, filed another claim against the defendant for the same collision. The proceedings were accumulated.

The first instance Court admitted the claims partially and assigned liability for the collision 70:30 per cent in favour of the plaintiff. On appeal, the Court of Appeals (CA) reversed the decision and dismissed all parties' claims. The CA stated that the collision was not duly proven and that it was not possible to assign responsibility to any party. The plaintiff and Minerva recurred the decision in cassation before the Tribunal Supremo/Supreme Court (SC). The plaintiffs alleged, among other things, an infraction of arts 4 and 12 of the Convention for the Unification of Certain Rules of Law with Respect to Collisions between Vessels 1910 (the Collision Convention 1910). Spain had ratified this Convention in 1923, while Cuba had not.

Held: The SC affirmed the CA's decision. Article 4 of the Collision Convention 1910 establishes that if two vessels are at fault, the liability of each vessel shall be proportionate to the degree of fault respectively incurred. If it is not possible to define the degree of the respective responsibility, the liability must be apportioned equally. The application of this provision supposes that the liability of the parties must be assigned equally as it was not possible to determine the proportion of fault of each vessel. However, art 12.1 of the Collision Convention 1910 establishes the application of the Convention by way of reciprocity. That principle does not allow the application to a non-contracting State of a norm that may be more burdensome than the rules that would be commonly applied, which in this case was arts 827 and 828 of the Code of Commerce. The SC interpreted this provision to mean that for member States to apply the Convention in the case of a claim by a non-contracting State that pursues the application of the Convention, its application would require a demonstration that the non-contracting State also complies with the Convention or, at least, does not violate it.