Of the ships built in Canada, the companies involved were Toronto Shipbuilding (later Redfern), Port Arthur and Collingwood. All the Canadian-built ships were VTE powered. Only 12 of these ships served with the RCN; a further 17 were built for the RCN but transferred to the Royal Navy in exchange for an equal number of s, as the RCN was in need of escort vessels. Fourteen ships were built for the United States Navy, but again were transferred to the RN on completion under Lend-Lease. Nineteen ships were ordered directly by the RN under the 1943 programme; a further six ships were ordered, but cancelled.