HMCS St. Catharines was a River-class frigate that served with the Royal Canadian Navy during the Second World War.

[4] The name "frigate" was suggested by Vice-Admiral Percy Nelles of the Royal Canadian Navy and was adopted later that year.

[4] 15 Canadian frigates were initially fitted with a single 4-inch gun forward but with the exception of HMCS Valleyfield, they were all eventually upgraded to the double mount.

[5] For underwater targets, the River-class frigate was equipped with a Hedgehog anti-submarine mortar and depth charge rails aft and four side-mounted throwers.

[4] River-class frigates were the first Royal Canadian Navy warships to carry the 147B Sword horizontal fan echo sonar transmitter in addition to the irregular ASDIC.

Beginning in February 1944, she was made Senior Officer's Ship of the group, that title being retained until September of that year.

[3] It must be said that not all the ships attacked the submarine at the same time as Gatineau and Kenilworth Castle both had to leave the fight after developing mechanical defects.

After working up in Bermuda, she returned only to begin a tropicalization refit in preparation for service in the southern Pacific Ocean.