The Centre examined certain specific problems, including craft for landing tanks, beach organisation, floating piers, headquarters ships, amphibian tanks, underwater obstacles, the landing of water and petrol and the use of small craft in amphibious raids By the end of 1939 the ISTDC had codified a policy for landings, and defended it at Staff College discussions. Operational experience during the Second World War introduced modifications to this landing policy, but it was essentially the policy used in the Torch and Husky landings four years later.