You'll have to attend the Army Officer Transportation Advanced Course (Seaborne) in Virginia - as I did. Like it or not, the US Army moves the bulk of wartime materials and does it through the Military Sealift Command.
The Military Sealift Command is a Navy asset headed by an Admiral. Yes, it does provide sealift to the Army as well as all DoD and various other Departments. For more info please follow this link:
http://www.msc.navy.mil/
The United States Transportation Command is the parent organization of the US Navy's Military Sealift Command (as well as the US Air Force's Air Mobility Command and the US Army's Surface Deployment and Distribution Command) it is currently headed by:
General Norton Schwartz, USAF
I believe that this command rotates but I don't have documentation.