 The first attempt, in March 1740, was essentially a reconnaissance in force by a squadron including ships of the line, two fire ships, three bomb vessels, and transport ships.Vernon's intention was to gather information on the city's topography and troop strength and to provoke a response that might give him a better idea of the defensive capabilities of the Spanish.In May, Vernon returned to Cartagena de Indias in charge of 13 warships, with the intention of probing the city's defences.