The Unfortunate Voyage: San Juan de Ulúa 1567-1569
Drake's first real step on the stage of history was his voyage to America under the command of his kinsman, John Hawkins. The enterprise began on October 2, 1567, when a fleet of six ships set sail from Plymouth. Only two of these ships were to return home, one commanded by Drake, in January 1569, and one by Hawkins in the following month.
The outstanding incident of this voyage was its disastrous ending. After profitable (though illegal) trade in the Spanish American ports, and the commission of sundry acts of piracy, the little English squadron put into the harbor of San Juan de Ulúa, Mexico, to obtain supplies and to repair their ships. While they were there, the annual Spanish flotilla of thirteen great ships sailed into the harbor, with the new Viceroy of Mexico, Don Martín Enríquez, on board. After a few days of negotiations, a pact was concluded by which the English were allowed to repair their ships and purchase ashore the supplies they needed, while the Spanish ships would anchor near them. But Don Martín treacherously ordered the pact to be broken, and a battle ensued. Only two small ships, the Minion , with Hawkins, and the Judith, with Drake, made their escape. The other ships, almost all the gains of the voyage, and 500 men were lost. The two ships were overburdened, and more men had to be abandoned on the Texas coast, only a few of whom ever reached England again.
The most important English source for this incident is John Hawkins' own narrative of the events of the expedition, which first appeared in Hakluyt's Principall Navigations , 1589, on pages 553-557. 
A Spanish version of these events is in Luis Cabrera de Cordova,Filipe Segundo Rey de España , Madrid, 1619, p. 515.  Both Drake and Hawkins are mentioned there, in the phonetic spellings usually found in Spanish sources, "Francisco Draque" and "Juan Aquines". Drake was also sometimes rendered "Drago" (= "Dragon") in Spanish texts, in reference to the dragonlike ferocity which they attributed to him.
A translation of the passage in Cabrera de Cordova is as follows (Libro VIII, cap. 10, p. 513):
[Queen Elizabeth] taking the advice of two Portuguese, fitted out two ships, and entrusted them, together with 500 men, to John Hawkins, a great seaman, who was a Devon man, and to another Englishman, Francis Drake. She promised them one third of the profits. They sailed for Elmina, a Portuguese trading post, and then called, with varying degrees of success, at places across from the Guinea coast to the island of La Margarita and Rio de la Hacha. As they were not allowed to trade even at Cartagena, they sailed on, and were sighted off Vera Cruz on 15 September. The royal officials at the port, thinking they were ships of the fleet expected from Spain, went on board to receive the mails. They were made prisoners and then set free. Hawkins and Drake received permission from the Viceroy of New Spain to stay in port while they did what was necessary to make ready to sail, and they kept the royal Treasurer as a hostage. They then entered the harbor of San Juan de Ulúa where six vessels heavily laden with silver were moored. Then thirteen ships of the fleet carrying the Viceroy, Don Martín Enríquez, and commanded by the General Don Francisco Luján, were sighted: as the English were in the harbor they did not try to enter. John Hawkins was afraid that these were the galleons built by Pedro Menéndez de Avilés, Adelantado of Florida, to protect the routes and convoys in the trade with the Indies, and which accompanied the fleets. He therefore sent word that he was in port by arrangement with the Viceroy, and was careening his flagship; and that this was because when he was sailing to Elmina, winds had blown him off course and that the need to save his ships was what had made him put in to land. The new Viceroy was mindful of the danger in which his ships stood by reason of the violent North winds in the Gulf; this caused him to come to an agreement with John Hawkins under which his ships were brought safely into port while hostages were given by both sides, and thus he was able to enter harbor. The authorities at Vera Cruz now became aware of the activities of which the English had been guilty, and 120 soldiers were embarked on board the fleet at night. The Viceroy set out for Mexico City.
Don Francisco de Luján, the Captain-General, did not feel obliged to adhere to an agreement made with raiders, and took the opportunity to break with them over the question of mooring places in the harbor. He decided to fight them, and ordered a considerable number of soldiers, armed only with daggers, to go aboard to call upon the English and to invite them over: during the banquet they were to be killed. This was done, and the guns of the fleet bombarded the English ships. A force of soldiers also captured the guns that John Hawkins had placed on a platform commanding the harbor to protect his flagship while he was careening her. Hawkins, meanwhile, ordered Francis Drake to load the gold he had acquired at Elmina into one of his ships, and to wait for him with it outside the harbor. He set fire to his flagship and directed the fight from the second largest ship: as things were going badly, he got away from the harbor in company with one other ship, leaving the remainder, with quantities of clothes, silver, slaves, rich stuffs, and many of his English crews dead, and he made sail. The ship accompanying him was cast up by the winds on the coast of Pánuco. John Hawkins arrived first at the Florida Channel and then got to the coast of Spain at the end of December with many men sick. On the other hand, Francis Drake got to England alone, and gave out that his commander had been wrecked. The gold and silver he hid, although the Queen put him in prison. This was the beginning of the career at sea of the greatest pirate of the age--the one who carried out more raids and robberies than any other.
The battle at San Juan de Ulúa had disclosed weaknesses in the fortifications, and consequently the noted Spanish military engineer Cristóbal de Eraso was ordered to prepare improvements in them. The plan and view, on two vellum sheets, of this celebrated fortress at the harbor of Vera Cruz, Mexico (see pages 56 and 57), are certainly the earliest extant depictions of it, and are also, so far as we can determine, the earliest extant drawings of military architecture in America.
It was in the vicinity of this fortress that Cortes landed in 1519, in his conquest of the Aztec empire. The port was a terminus of the Spanish treasure fleets which carried to Spain the silver and other precious metals of Mexico, as well as the Far Eastern goods sent to Spain from Canton via Manila, Acapulco, Mexico City, and Vera Cruz.
At the time of the battle between the Hawkins-Drake forces and the Spaniards the fortress consisted of a tower, with embrasures for artillery and a gun platform on the top, and a stone wall, part quay, part fortification, 300 feet in length along the shore. Ships were moored to the wall by large iron rings shown here and in later drawings, with one end anchored out from the wall. On the view are the proposed additions: a 138-foot extension of the wall and a large tower with two gun platforms. These additions greatly increased the strength of the fortification.
The other piece, a ground plan, displays an even more ambitious scheme; the existing rampart-quay is incorporated as one wall of a quadrangular fortress, about 300 feet square, with a tower at each corner. This improvement was not carried out in the 16th century; only in 1712 was a somewhat similar fortress erected. The lengthening of the rampart was done soon after 1568, however; the next extant plan, that of 1590, shows it in this extended form.
The Spanish American ports had, up to the time of Drake, been very lightly fortified. The sudden need to provide such buildings was a severe drain on the Spanish treasury, and this may have caused expenses which exceeded the cost of the actual damage.
As has been pointed out by D. W. Waters, "the immediate economic lesson of San Juan de Ulúa for Englishmen was that if they wanted to trade with the Indies, they would have to fight for the right under one guise or another, and that the wealth of the Indies could be won only by hard endeavour on the high seas." ( Art of Navigation in England , p. 120). Mr. Waters likewise describes the importance of this battle in the history of the English navy, and for the art of navigation.