Military Sealift Command was created in 1949.
Military sealift command
The Military Sealift Command is part of the United States Navy. They provide transport ships for the navy which may carry supplies such as fuel, food, or weaponry.
Military Sealift Command
Sealift Incorporated was created in 1975.
Military Sealift Command (MSC)
Nanjing General Hospital of Nanjing Military Command was created in 1929.
You might be interested in the Military Sealift Command. http://www.msc.navy.mil/
The main difference in any country is mission. The "Navy" is a branch of the government in questioned who uses military built ships as weapons. The Merchant Marines or Merchant deal in Sealift or moving materials from one place to another. The Merchant Marine may also defend the Merchant ship he or she is on but the ship is not necessarily used by the military. Now in the US Navy we have MSC or Military Sealift Command. MSC moves materials around the world for the military but is more of a merchant Navy. Also the merchant navy may have military sailors stationed on them such as many of the US Navy's oilers.
you won't be an actual part of the military but you will serve in our merchant fleet. Perhaps if the US Navy is not for you then perhaps the Military Sealift Command may be to your liking where you would serve on military transport vessels(not combatants).The Merchant Navy is a non-combatant commercial fleet, which deals with transporting cargo and occasionally, passengers, by sea.
The 31 Maritime Prepositioning Ships (MPS) are part of the United States Military Sealift Command's (MSC) Prepositioning Program. They are strategically positioned around the globe to support the Army, Navy, Air Force, Marine Corps and Defense Logistics Agency.
It is not a military custom it's a military command, 'stand at ease' means to relax from the 'stand to attention' command.
Change of Command.