Prior to WWI, belligerents observed "Prize" or "Cruiser" rules, which stated that the ship couldn't sink a passenger ship, only a merchant vessel of an enemy nation, and that the crew/passengers aboard any vessel must be clear and safe before it was sunk. These rules were from the days of sailing vessels, and with WWI and the advent of submarine warfare and modern weapons, it didn't take long to determine that those rules were obsolete. This was essentially the basis for Germany's initial submarine warfare policy.
Though Germany initially tried to comply with Prize Rules, as WWI submarine warfare progressed, it became apparent that those rules were outdated and even dangerous. With its practice of warning ships and allowing passengers and crew to leave prior to sinking, it meant that the attacking submarine would be a sitting duck to any enemy vessels or aircraft. The ship's crew only needed to summon military assistance by radio, and the passengers and crew could take their time to evacuate the ship, giving time for aid to arrive.
By engaging in Guerre de Course (merchant warfare) instead of the traditional Guerre de Escadre (Fleet to Fleet sea battles).
It sounds as if you are looking for submarines.
1. Germany=Submarines 2. Japan=Aircraft Carriers Germany pursued a naval war of "Guerre de Course" (Commerce raiding) Japan pursued a naval war of "Guerre de Escadre" (Fleet warfare)
Type of naval warfare in which submarines sink vessels such as freighters and tankers without warning, as opposed to attacks per prize rules (also known as "cruiser rules").
Colin Mayers has written: 'Submarines, admirals and navies' -- subject(s): Naval History, Naval art and science, Naval operations, Submarine, Submarine warfare, World War, 1939-1945
sucking balls
Weak naval powers, such as Germany during both world wars, had to revert to "Commerce Raiding" (Guerre de Course) as they did not have a powerful enough surface navy to challenge their enemies on the high seas. Thus their submarines fought primarily merchant warfare; and not fleet actions (Guerre de Escadre).
There were subs in the 19th century, but they were really a part of naval warfare from World War One to the end of the Cold War. If large scale war breaks out in the near future, expect submarines to be a huge factor on the ocean front.
Because the German navy was not a strong navy, they had to rely on submarines to attack merchant ships...Guerre de Course (Commerce Raiding).
Naval Special Warfare Group was created in 1956.
Naval Undersea Warfare Center was created in 1869.
Naval Warfare - 1905 was released on: USA: October 1905