Confidentiality sounds like one of the more reasonable explanations, but it looks like the Coast Guard has its own set of approvals http://www.uscg.mil/hq/cg5/c

Confidentiality sounds like one of the more reasonable explanations, but it looks like the Coast Guard has its own set of approvals http://www.uscg.mil/hq/cg5/cg521/ http://www.uscg.mil/hq/cg5/cg521/