Fortifications in the Shannon Estuary: Foynes Island Battery

Just over ten miles upstream of Tarbert a battery was placed on the western point of Foynes Island, another location suggested by Wellington and by Dumouriez. This was an earthwork battery for six 24-pounders, which would have been capable of commanding the full width of the river, which is a mile wide from Battery Point across to the Co. Clare shore to the north-west. Remains of the battery survive on the site.

The Shannon Estuary batteries were well placed to cause maximum damage to an enemy fleet sailing up the river or attempting to land an invasion force, but they would not have prevented a large-scale French landing. The batteries also provided protection for vessels anchored within range of their guns, otherwise vulnerable to attack by enemy ships of war or privateers. In 1804 the gunboat establishment in Ireland included five gun vessels in the Shannon Estuary armed with 18-pounder guns and 32-pounder and 18-pounder carronades.^[6] These small craft operating in the shallow waters of the estuary could not be pursued by deeper-draught vessels such as ships of the line or frigates.