Vernon's force appeared off Portobelo on 20 November 1739. The British ships entered the bay prepared for a general attack, but a wind coming from the east obliged Vernon to concentrate his ships on the
Castillo del Hierro ("Iron Castle"), a harbour fort. The Spanish garrison was caught unprepared. When some Spaniards began to flee from several parts of the fort, several landing parties were sent inshore. The British sailors and
marines scaled the walls of the fort, struck the Spanish colours in the lower battery, and hoisted an English ensign. The Spaniards surrendered then at discretion. Of the 300-man Spanish garrison, only 40 soldiers led by Lieutenant Don Juan Francisco Garganta had remained in the fort. Once he captured Castillo del Hierro, Vernon shifted his ships against Santiago Fortress, sinking a Spanish
sloop and causing other damage. At dawn on the following morning, the Spaniards requested terms. Governor Francisco Javier Martínez de la Vega y Retes surrendered in the afternoon. Portobelo was occupied by the British at the cost of three killed and seven wounded. Three prizes were taken: an armed
snow, which was renamed
Triumph, and two 20-gun
guarda costas. The British occupied the town for three weeks, destroying the fortress and other key buildings, and ending the settlement's main function as a major Spanish maritime base, before withdrawing. ==Legacy==