The Bellona class was conceived as general purpose escorts and were termed 'Frigates' in the Amazonian Navy. The first dozen followed the Batch one layout with three twin 20mm as the light AA armament, the only alteration to that was the replacement of the 'B' 20mm mounting with a hedgehog mortar. The next Batch two ships had the 40mm and Hedgehog upgrades which made the ships much more capable. The number of ships in production increased from the original six ordered on the outbreak of war. A further six being ordered in 1940, then another eight in 1941. The eight ordered in 1941 were to the 40mm and Hedgehog standard and the further twenty-four ships ordered were to that standard as well. The last of the class completed in August 1945.
The main claim to fame for these ships in the Amazonian Navy was not just that they were built in three different dockyards, but the way the material for the ships was assembled was new. Parts for the ships were manufactured in non Navy production centers, railroaded to the port and then put together by non Navy building yards. This also applied to the diesel engines fitted to the ships. The diesels were the low power versions fitted to fishing trawlers and similar civilian vessels. This meant the ships added no strain to the already busy Navy Yards trying to complete all the hundreds of thousands of tons of shipping requested/ordered by the Navy.
These were tough little ships and ended up serving as convoy escorts all over the place. From Russian convoys to the terror of the Atlantic convoys and the balmy Pacific trade routes, these ships saw them all. Fighting with German cruisers and destroyers with one being lucky enough to be in the Philippines in 1944 to take on the might of the Japanese Navy and proudly say 'we fired at the Yamato and Mussashi'.
The Hedgehog forward firing mortar system was a real game changer for escort versus submarine. An attack with depth charges only, had a 7% chance of success. Using Hedgehog increased that to over 25%. It is eventually the quality of the Asdic/Sonar unit that made the ahead throwing mortars more successful. The US Weapon A system, British, Squid, and Limbo all became more accurate as the electronics serving them got better.
