The assault begins
After a few probing attacks at the various forts along the sea, the battle began in earnest on April 1. Vernon’s first job was to take control of the narrow mouth of the harbor, Bocachica, so that he could move his fleet into the bay.
The three forts at Bocachica were reinforced by a chain stretched across the entrance, and behind the chain Don Blas had four Spanish warships anchored to add their firepower to that of the forts. It was in this bloody battle that Don Blas was wounded again, this time in his good leg.
San Felipe Fortress
After three days of heavy bombardment, Don Blas decided to fall back to the next line of defense. He brought the survivors to the next pair of forts, Castillo Grande and Manzanillo. Between these two forts Don Blas sank seven ships and moored two man o'wars in the line of sunken ships to use their guns to reinforce the fire from the forts.
After causing considerable damage to the English, these two also were sunk to close off the channel. Unfortunately, the current changed at the last moment and one ship sank partly sideways leaving a small, hazardous gap in the line. This left only the small fort Boquerón (now the site of the Club de Pesca), which was quickly destroyed. Then came Vernon’s big disappointment. He had planned to bombard San Felipe from his ships but discovered that it was so high that to get in range, he would have to come in very close. To do so would have placed his fleet in a disastrous position directly under the guns of San Felipe. He realized he would have to unload his cannons and attack by land.
On April 5, forces were landed and after one of the bloodiest battles in British history, they took possession of the convent of La Popa, on the high hill overlooking the city, from which they could observe everything the Spanish were doing.
Vernon Stopped by Spanish Military Engineering
Vernon now felt that victory was within his gasp, for there was nothing between him and the great fortress of San Felipe. He landed the balance of his forces and equipment and before dawn on April 9 he attacked with three columns coming from three directions.
Both sides were well motivated. The English forces knew that it had been nine months since the last shipment of treasure, so they believed that the fortress contained a fortune. The Spanish had no place to retreat if the fortress fell. The battle raged fiercely all day, but by dark it was Vernon’s turn to retreat, for little had been accomplished and his losses were substantial. While trying to regroup, he kept receiving reports of wide spread illness among his troops. Sir Chalamar Ogle himself had such severe stomach pains that he had to report himself unfit for duty.