You can obtain Merchant Marine service records by writing to NARA at this address:

Service Records of mariner killed during World War II:

Old Navy/Maritime Reference
Archives I -Textual Services Branch
National Archives and Records Administration
700 Pennsylvania Avenue NW
Washington DC 20408

Include the following information in your request:
William B Wicke
Merchant Marine
Service Number 35329
Date of death, Ship Name, date & place of sinking
Any other info you can provide might be helpful in locating the records.

You might find some info on the Merchant Marine website.
http://www.usmm.org/

Larry