Civil War Leadership and Mexican War Experience

Samuel Du Pont and the Naval Blockade

56 Samuel Du Pont and the Naval Blockade An early part of the U.S. strategy in the Mexican War was to blockade ports on Mexico’s Gulf and Pacific coasts to prevent arms and ammunition from entering the country from Europe (Carney, Gateway 9). Accordingly, in July and August 1846 John Drake Sloat and Robert Stockton, successive commanders of the Pacific Squadron, established control of the Pacific coast from San Francisco to San Diego. On August 19, Stockton ordered Joseph Hull to blockade Mazatlan and Samuel Du Pont to blockade San Blas, about 125 miles south of Mazatlan. Stockton’s aim was to seize Acapulco, about 500 miles south of Mazatlan, and use it in support of a joint army-navy expedition into Mexico. Thus began Du Pont’s experience with blockading, an experience he would repeat on a much larger scale in the Civil War. THE FIRST BLOCKADE OF MEXICO On September 2, Du Pont, commanding the Cyane, captured two Mexican vessels in the harbor of San Blas. He then sailed north to the pearl-fishing town of La Paz, seized nine small boats there, and secured a promise of neutrality from the governor of Baja California. Moving north some 150 miles to Loreto, Du Pont seized two schooners on October 1, and on October 7 he shelled Guaymas and burned a brig there. On November 13, Du Pont followed Hull to San Francisco to replenish his dwindling supplies (Bauer 344; Weddle, Tragic Admiral 27). The blockade was lifted. The first blockade of Mexico’s west coast had lasted about four weeks. Its SAMUEL DU PONT AND THE NAVAL BLOCKADE 57 ineffectiveness taught Du Pont two key lessons: a blockading force must have enough ships to adequately cover all ports, and blockading ships had to be sustained with supplies and maintenance facilities to enable them to remain on station for extended periods. Du Pont’s biographer Kevin Weddle notes, “These experiences would serve [Du Pont] well during the Civil War” (Tragic Admiral 28). But first the navy would try again off California. ANOTHER FAILURE Orders for a second blockade were issued on December 24. Again, it would be an ineffective effort. As other ships left the blockade for resupplies at San Francisco, Du Pont was left by himself. To provide the friendly inhabitants of La Paz and San Jose del Cabo with some semblance of protection, Du Pont resorted to sailing the Cyane back and forth between San Jose and Mazatlan . This opened Mazatlan to commerce, breaking the blockade. Eventually, Du Pont sailed for Hawaii for resupply (Bauer 345; Amero). These experiences showed Du Pont firsthand the practical difficulties of a blockade. Such an undertaking is very resource intensive in terms of both ships and supplies. To maintain the blockade, ships cannot abandon their positions to get supplies. Either the resupply points must be close enough to facilitate the blockade or additional ships must come in to replace the departing ones. Again, Du Pont would carry these lessons into the Civil War. Mexico had given him, according to Robert Selph Henry, “a foretaste, on a most limited scale, of the duty which [Du Pont] was later to undertake on a grand scale off the south Atlantic coast of the Confederate states” (Mexican War 210). Indeed , Du Pont was one of the few officers in the Federal navy who would bring blockading experience into the Civil War (Weddle, “Blockade”). THE CIVIL WAR BLOCKADE On April 19, six days after Fort Sumter, President Lincoln issued a proclamation declaring the blockade of the Southern states from South Carolina to Texas. On the 27th, the blockade was extended to Virginia and North Carolina. 58 THE FEDERALS As in Mexico, the purpose of the blockade was to isolate the Confederacy from European trade. The terms of the proclamation were: Now therefore I, Abraham Lincoln, President of the United States . . . have further deemed it advisable to set on foot a blockade of the ports within the States aforesaid, in pursuance of the laws of the United States and of the Law of Nations in such case provided. For this purpose a competent force will be posted so as to prevent entrance and exit of vessels from the ports aforesaid. If, therefore, with a view to violate such blockade, a vessel shall approach or shall attempt to leave any of the said ports, she will be duly warned...