I managed to pick up a copy of Secret Victory by Liam Nolan and John Nolan on a visit to Dublin last year. While I had a vague awareness of the role of the Helga and other ships in the Easter Rising, the sinking of the Lusitania and RMS Leinster and a passing awareness of anti submarine operations by air ships I didn't have a good grasp of naval activity in Ireland, either British or American.
The following books have now been acquired and read :
Pull Together by Admiral Lewis Bayly
Danger Zone by Edward Chatterton
My Mystery Ships by ADmiral Campbell
Liffey Ships and Shipbuilding by Pat Sweeney (the Helga claimed to have sunk a U boat off the Isle of Man on 4th April 1918)
The Sea Hound by Daire Brunicardi
RAF and US Naval Air Service in Ireland 1913-1923 by Karl Hayes
All good reads offering different insights into naval issues in Ireland during WW1 (and beyond in the case of The Sea Hound and Liffey Ships and Shipbuilding).