HMCS Saguenay (I) was the first RCN vessel to carry the name. Laid down in 1929 she was the first Canadian made-to-order warship.
The story of the first made-to-order warships for the Canadian navy (HMCS Saguenay and HMCS Skeena) in Canadian Naval Review Vol 12, #2
The first Canadian destroyer to carry the name HMCS Ottawa was launched as HMS Crusader at Portsmouth Naval Dockyard in 1931. Like her sister HMS Comet (later HMCS Restigouche) she was commissioned into the Royal Navy in 1932 and assigned to the 2nd Destroyer Flotilla of the British Home Fleet.
Unique amongst the Canadian River-class destroyers, HMCS Gatineau—built as HMS Express by Swan Hunter & Wigham Richardson Wallsend-on-Tyne—had been originally fitted as a minesweeper, and had twin sponsoons aft for the mine rails (never carried in Canadian service). She would be the sole E-Class destroyer to serve in the RCN.