San Juan Nepomuceno was a Spanish ship of the line launched in 1765 from the royal shipyard in Guarnizo (Cantabria). Like many 18th Century Spanish warships she was named after a saint (John of Nepomuk). She was a solidly built ship of proven seaworthy qualities. Her sister-ships were San Pascual, San Francisco de Asis, San Lorenzo, Santo Domingo and San Agustín. She rendered numerous important services to the Armada (fleet), some of them in the Caribbean where she participated in several sieges and was distinguished in 1779.