Three years later the fortress was occupied only by a constable and porter, and was in much need of repair and a garrison.
Sir George Carew received an order to repair the building and provide a ward in 1600, so that it would be a fit residence for the President. He reported that unless part of the town were removed it was impossible to make the fortress really strong, and so he was merely able to add some storehouses, which he regretted, “for that this insolent town has need of a straight curb.”
The death of the President prevented the intended repairs being carried out, and two or three hundred pounds were needed shortly after to roof the towers and the Great Hall, which had been begun, so that the assizes might be held in it. The arms were being much injured through the stronghold not being weather-proof.
In 1602 Father Archer informed the Spaniards of a way they could surprise the castle, he having learned it in Limerick during the previous rebellion.
The plan consisted of two or three Irish galleys coming up the river at night with the tide, and carrying about three hundred men, who would at once force the northern gate by breaking the wooden door with a “pittarr,” as no watch was kept there. The castle once in their hands, attacks could be made from all the other sides of the town.
King James I. granted a charter to the city of Limerick in 1609, from which the castle is exempted.
In 1608 it was stated that a cellar existed under the stronghold, which could be entered from the town without observation. The following year great dilapidations are reported by Sir Josias Bodley. He said that the round towers near the river were so undermined by the water that a cart might pass below their foundations. He repaired the walls and towers, and built the square platform for cannon on the town side. He surrounded the whole with a moat and erected the drawbridge. A constable’s house was still needed.
Repairs were again required in 1618 and 1624.
Captain George Courtenay with two hundred men maintained a most gallant siege in 1642. Though short of provisions, and with a garrison who were not all regulars, he managed to keep the Irish forces at bay for a considerable time.
The besiegers threw a great boom across the Shannon, formed of aspen trees fastened together with iron links, so as to prevent Sir Henry Stradling provisioning the castle by the water gate.