Chasers in the Caledonian Canal.
The first photo shows SC 181 and SC 356. The second picture shows the bows of two chasers preparing to pass through the locks. These are probably post-war photos. It appears that the submarine hunting equipment such as the bearing indicator and K-Tube have been removed.
From the collection of SC 181 crewman Donald Arthur Huntley, courtesy of his grandson, Dr. William W. Huntley.