but defensive measures like guns against surfaced submarines and low-flying aircraft were slowly added. By the spring of 1945, around 1,700 men were registered as gunners on Norwegian vessels, and in addition, there were some 900 British gunners. The vessels also received degaussing against magnetic mines, and seamen were issued watertight survival suits if the ship had to be abandoned. An important part of security was strict secrecy regarding routes and destinations, as made famous in the slogan "Loose lips sinks ships". Despite those and other measures, losses were high. Of a total of about 30,000 Norwegian seamen, 3,670 lost their lives as a result of the war at sea, together with 977 foreign crewmen. 706 ships were lost to enemy action. British pressure for more tonnage Even though most of the Norwegian ships were sailing for the Allies, the British in April 1941 wanted more. That was a delicate dilemma for Norway and Nortraship. On one hand, Norway, was allied with and dependent on Britain, but on the other, the "free ships" that were sailing from the neutral US generated hard US dollars, much needed for reconstruction of Norway after the war. Moreover, voyages to the British Isles were the most dangerous, and Nortraship argued that the modern Norwegian tankers would be better used in other trades. A more hidden agenda was the Norwegian fear that the British and the US would use the war to secure an unfair competitive postwar position. An initial mutual understanding was reached in a meeting in the British Ministry of Shipping on 19 March 1941: Nortraship was to transfer 500,000 tons of its "free ships". Even though the agreement was not officially signed until October, the work of tonnage transfer started. Nortraship London under Hysing Olsen tended to favour the British, and Nortraship New York under Lorentzen had a more business-like stance. As Allied losses increased dramatically, the British on 29 April 1941 demanded all Norwegian ships. That was a total surprise for the Norwegians. Nortraship's New York office tried to influence the US through the US Maritime Commission, arguing that Norwegian vessels were much needed for US import and export although only 30% of it was on US keel in 1939. After hard negotiations with both the British and US shipping administrations, a new tonnage agreement was signed on 10 October 1941, effectively letting Britain charter three fourths of all Norwegian vessels.