In the negotiations, Nortraship tried to secure the US dollar freight income, to obtain a more equal footing with the British in governing the Allied merchant fleet and to receive assurances regarding Norwegian shipping rights after the war. In the currency issue, Nortraship's stance seems to have prevailed, but in governing the Allied merchant fleet, an Anglo-Norwegian Shipping Committee was established, but despite scores of meetings, it handled the issue only superficially. Finally, the British gave only vague promises as to their postwar shipping policies. In the two years from 9 April 1940 to 9 April 1942, a total of 157 Norwegian tankers made 615 voyages and delivered 6.9 million tons of oil, supplying about a third of the total requirements of the British Isles. Tankers with clean/dirty oil and spar decks Before the age of specialised supertankers, the vessels could take "clean" or "dirty" oil or change between them. The "clean" oil would be refined, as gasoline, and "dirty" was unrefined crude oil or heavy oil. A vessel carrying only "clean" oil would deteriorate faster and so an ongoing fight from both Nortraship offices was to get as many "dirty" cargoes as possible. Nortraship had a tough adversary in the British Ministry of War Transport, which produced statistics showing that British vessels were carrying more "clean" cargoes than the Norwegian. The US War Shipping Administration were more accommodating in the issue and let several Norwegian vessels change to "dirty" cargoes. In peacetime, it is very rare for a tanker to take deck cargo. The war changed that since there was a huge demand for transporting large pieces of war equipment from the US to Europe and other war theatres. It was quickly figured out that tankers had large uncluttered deck areas, which could be used for volume cargoes, like airplanes and trucks. The tankers, however, had to be equipped with so-called "spar decks" where the cargo could be secured. On 1 January 1944, a total of 58 Norwegian tankers were equipped to take deck cargo. The installation of the spar decks was paid for by the UK and Nortraship did not ask any payment for deck cargo, as the charter for the oil cargo already covered the costs. US enters war Nortraship's situation as a shipping enterprise changed dramatically when the US entered the war on 7 December 1941. When the US was neutral, Nortraship could benefit from the