An Introduction to Ships of the Convoy War - the Battle of Atlantic in Steel Part 3 Frigates

ASDIC, ahead-thrown weapons, the Leigh Light, centimetric radar, and signals intelligence changed the terms of the Atlantic escort war.

The Second Happy Time illustrates why a navy's immediate escort strength matters more than ships planned or still under construction.

New technology and the arrival of River-class frigates helped reverse the Atlantic balance during the spring of 1943.

The River class may have been a mass-producible sloop development, which complicates the usual description of frigates as faster corvettes.

Of 151 River-class frigates completed, only five were lost during the war, while HMAS Diamantina is the only one preserved in substantially original condition.

River frigates were intended to defeat a U-boat using its deck gun on the surface, giving convoys a capability that corvettes might struggle to provide.

Three hard-fought convoy battles show how radar, aircraft, escorts, and increasingly numerous anti-submarine weapons combined against U-boats.

The Loch class sought a lighter, faster escort with two Squid mortars and striking anti-submarine firepower.

Bay-class variants reveal how a common frigate design could be adapted toward either submarine hunting or air defence.

Loch, Bay, River, Captain, and earlier escort types share a design lineage that wartime labels can obscure.

The Tribal class marks a transition between two phases of Royal Navy destroyer design, and the distinction describes changing ideas rather than ship quality.

The Hunt class and older V and W destroyers illustrate two routes to escort capability: purpose-built ships and First World War designs adapted during the next war.