Their mission was to intercept the Spanish Admiral Pascual Cervera y Topete and his fleet steaming from the Cape Verde Islands to the Antilles.

The Fleet reached Cape Haitien, Haiti, on 8 May, where Rear Admiral Sampson telegraphed Washington to report updates and await for further instructions.

The following day, a Spanish auxiliary cruiser, name unknown, and Yale fought a minor battle off San Juan.

Finally on 11 May, a day away from Puerto Rico and after receiving no new information about the Spanish fleet, William Sampson boarded Detroit and issued his orders.

Detroit was to lead the U.S. battle line up San Juan's bay, their orders where to initiate a bombardment of the enemy positions if fired upon.

After failing to stop his vessels, Sampson ordered Iowa to train her guns on the nearest enemy stronghold, the Morro castle.

The rough seas made the U.S. ships wobble back and forth, disallowing the sailors a steady platform to fire from, this also attributed to stray rounds.

Possibly to avoid an international crisis with France, no major American attack was made on the Spanish gunboats as they were quite close to Amiral Rigault de Genouilly.

After the battle, the commanding Spanish Military Governor, Manuel Macías y Casado, confirmed that two of his troops were killed while manning the few different batteries and another 34 injured.

The number of refugees was reportedly so large that San Juan's streets were almost deserted, with the exception of the several hundred strong Spanish garrison.