This Portuguese ship from the time of Joao V weighted 550 tons and was armed with twelve 10 pound cannons. It was a slow ship and was ideal for the transportation of troops in long distances as it could carry more than 200 men. It was one of eight ships of the Anglo-Portuguese fleet, under the command of John Mac Namara, who tried to conquer Colonia, which at the time was under the control of the Spanish Gobernador Ceballos.
In December 1762 the fleet took refuge in Atlántida, avoiding a summer storm, but the Inmaculada Concepción broke its moorings and crashed on the coast of the Fortín de Santa Rosa. Even nowadays, on certain occassions, parts of it can be seen buried in the sand.