In 1587, the Genoese military engineer, Fabiano Bursotto, who had been engaged by the Crown to design new harbours in Palermo and Málaga, had visited the Rock in order to inspect the Old Mole. As a result of his visit, the area near to the mole was dredged properly due to the sand and waste which had accumulated and which made it unusable for shipping berthing there. The works were supervised by the Maestro Mayor of the City, Bartolomé Quemado, with the project continuing until, at least, 1591.
By 1604, the Old Mole was again in a dire state, especially following the damage caused by the winter storm. In this respect, another military engineer, the esteemed Sienese Tibúrcio Spannocchi was brought in to remedy the situation. A detailed plan of the Old Mole area, executed a year later, showed his proposal which was to increase its length by a couple of hundred feet. In 1605, a plan was developed to undertake the repairs on the Old Mole, the plan included extending the mole by a few hundred feet amongst other suggestions, unfortunately, a lack of capital meant practically no work was carried out. This apparently had dire consequences as on the 25th April 1607, a Spanish fleet under the command of Don Juan Álvarez Davila was heavily defeated in the Bay by a Dutch fleet commanded by Admiral Jacob Van Heemskerk. The fateful outcome of this naval battle, later known as the Battle of Gibraltar, was partly attributed to the fact that there was a lack of a proper mole in Gibraltar were the Spanish fleet could have taken shelter and this possibly contributed to the Spanish defeat of its armada.