See How_many_times_a_year_do_ships_sink
103 merchant ships were sunk in world war one
3
Roughly 2,000 merchant ships in WWII.
No,in fact in spite of what you think, there is no organization called "the merchant marine"The phrase merchant marine refers to an industry, just like the phrase commercial airlines refers to an industry.The phrase merchant marine refers to the commercial shipping industry, ships like container ships, tankers, bulker, break bulk ships ect, tha are owned and operated by private companies like Matson Navigation, Pasha Lines, TOTE, ect.Merchant mariners are civilian employees who work on merchant ships and just like there are legal requirements for those who work on aircraft there are legal requirements for merchant mariners, the federal agency that licenses merchant mariners is the U.S. Coast Guard.The industry itself is regulated by the U.S. Coast Guard, The Maritime Administration and international agreements.Now that you have that in mind, lets go into the area that leads to much confusion;The federal government and many state and local governments also operate ships, and the people who work on these ships also have the same licenses as those who work on commercial ships., in many cases people move from one to the other, some military ships are even operated by private companies, in fat the military does not transport much of its own cargo, they depend on merchant mariners for that, both those employed directly by the U.S. government (called civmars) by government owned and ships operated by private companies, and by commercial ships.This is why merchant mariners, though not part of the military had a higher death rate than the military during WW2, and for that reason in the 1980's merchant mariners who had sailed during WW2 were granted veteran's status.
22 Galleons and 108 armed merchant ships
3,000 Allied ships (175 warships; 2,825 merchant ships)
one Cal State
20 0000
34 warships and 163 armed merchant vessels
Primarily over 2,000 merchant vessels, with a sprinkling of allied warships.
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.