Joining H28 at this time was Sub-Lieutenant Edward Preston Young, who was the first Royal Naval Volunteer Reserve (RNVR) officer ever to be admitted to the Submarine Service.

[13] Following the fall of France in June 1940, these training submarines undertook operational patrols in the North Sea as an anti-invasion precaution.

On 11 October 1940, H28 commanded by Lieutenant E A Woodward, unsuccessfully fired four torpedoes at a small enemy merchant ship off the Netherlands coast,[14] and subsequently escaped after being depth-charged by escort vessels.

[15] Following the loss of H49 shortly afterwards, operational patrols by the other H-class submarines were suspended, and the flotilla moved to Rothesay on the River Clyde in December 1940 to resume training duties.

These included giving new officers and ratings seagoing experience, as well as providing live targets for escort vessels practicing anti-submarine techniques.