These vessels were built of teak and launched at Kalewa, on the Chindwin River in Burma, by Royal Engineers of the British 14^th Army. Commissioned and manned by the Royal Navy, they operated with success against the Japanese on the Chindwin and Irrawaddy Rivers during the closing stages of the war in the Far East. Both received hits in action with the enemy, on whom they inflicted a considerable number of casualties, despite leaking profusely!