The Limerick Navigation was in five sections — three canals with river sections in between — and joined Limerick to Killaloe and the rest of the inland Shannon. The canal sections had locks, each controlled by a lockkeeper who lived on site. The job passed from generation to generation: some of the lockkeepers’ cottages are still inhabited by descendants of the lockkeepers.
Cussane was the furthest downstream of the three locks on the Killaloe section of the canal. It was covered by water when the Ardnacrusha hydroelectric scheme created the “flooded area” below Killaloe. If memory serves, Cussane was known as Crowe’s Lock.
In the online searchable catalogue of the Registered Papers of the Chief Secretary’s Office in the National Archives, there is a letter dated 15 February 1830 [CSO/RP/1830/815]
[…] from James Saurin, Henry R Paine, and John Radcliffe, [Directors General of Inland Navigation], Board of Control, [Dublin], to Hugh Percy, 3rd Duke Northumberland, [Lord Lieutenant of Ireland, Dublin], recommending Denis Crow to succeed Lott Corboy sheriff as lockkeeper on the Limerick Navigation.]
There is also a letter dated 2 June 1830 [CSO/RP/1830/836]
from James Saurin, J Armit, and Henry R Paine, [Directors General of Inland Navigation], Navigation Office, [Dublin], to Hugh Percy, 3rd Duke Northumberland, [Lord Lieutenant of Ireland, Dublin], recommending dismissal of Simon Johnston, lockkeeper on the Limerick Navigation, for irregularities and for deception; asking to employ Michael Gully in his stead, for Stg£9-4-9 per annum.
Gully’s Lock is at Gillogue, on the central canal section known as the Plassey–Errina Canal.