Anker Pedersen / Merchant Marine WWII era

Hi! I'm researching my family from Denmark and was wondering if anyone here can point me in the right direction! In my fathers WWII Servicemans address book i found this address for my Great Uncle Anker who was a merchant marine from Denmark. Anker Pedersen MTK Bostonian %Pna Danish Corp. Shipping Operating N.Y., N.Y. I was told that Anker was in and out of America alot and I believe I have found him several times at Ellis Island listed as a member of the ships crew for the Scandinavian-American Line; The United Shipping Co. Copenhagen; Funch, Edye & Co. New York. I would like to know where can I research records of Danish Merchant Marines? Please help! THANKYOU![:D]