Like all Flower class corvettes, HMS Clematis was built on the heavily revised design of the whale catcher, Southern Pride. A thirty foot section was added to the front of the ship, the type of keel was changed, additional quarters and a larger bridge were added as well. After adding bits, taking some other things off, and moving compartments around, a barely acceptable convoy escort came to be. Because time was critical, these ships were produced in civilian yards in England.
They barely had time to build the Flowers, much less build them to the warship standards of the Royal Navy, so they were built to civilian specifications as issued by Lloyds of London. This meant, among other things, that the initial Flower class corvettes had light framing and scantlings and lack of redundancy for critical equipment. There were no reinforced bulkheads in the interior of the ship except forward.
Flower class corvettes were simply civilian ships with light armament and depth charges added. In the beginning of the war, it was thought the corvettes would be used as coastal convoy escorts. They actually weren’t designed for deep ocean work but that’s what was needed and off to the deep ocean they went. They were used almost exclusively as escort ships for North Atlantic convoys for the entirety of the war.
The first fifty corvettes produced didn’t even have thermal insulation on their interior sides so everything was always damp. Clothes never completely dried. The corvettes were cold. Ventilation was terrible and that combined with the cramped quarters of the men and the dampness caused outbreaks of tuberculosis.
Being a rating on HMS Clematis wasn’t an easy job and the conditions were far worse than a jail on land. Officers didn’t have it much better. They each had their own small cabin but their cabins normally had two or three inches of water in them most of the time because the deck seams split in heavy seas.
Back to the convoy: upon deciphering the signal from HMS Clematis himself, the convoy commodore, who controlled the merchant ships, no doubt with the concurrence of the SOE, ordered the convoy to disperse. (Convoy commodores were retired Royal Navy admirals brought back into active service with the temporary rank of “Commodore.” While they were older and outranked the Senior Officer Escort, the Royal Navy officer who commanded the escort vessels, by unspoken agreement they took orders or “suggestions” from the SOE. The few Commodores who did not do this were relieved. Commodores also had several Royal Navy signalmen assigned to them.)
Meanwhile, HMS Clematis was steaming full ahead at the German ship and firing her single turret gun as fast as she could while taking broadsides from the Admiral Hipper, all of which missed. Clematis also made smoke to hide the convoy. Typically warships made smoke by using special smoke generators mounted in the stern.
Admiral Hipper was at the beginning of her commerce raiding cruise and did not want to engage three British cruisers as well as be subjected to air attack so after sighting the additional ships, the Admiral Hipper broke off the engagement. When the British equivalent of the US Secretary of the Navy (at that time) reported this to Parliament, he confessed the signal by HMS Clematis “brought tears to his eyes.”
Convoy: Merchant Sailors at War 1939-1945 by Philip Kaplan and Jack Currie
Atlantic Escorts: Ships, Weapons, and Tactics in World War II by David K Brown
Anatomy of the Ship: The Flower Class Corvette Agassiz by John McKay and John Harland