The general term is a pirate.
A person who attacks and robs ships is typically referred to as a "pirate." Pirates often operate in maritime areas, seeking to steal goods and valuables from vessels on the open sea.
It attacks ships & whales but i don't think it attacks humans!
Some attacks were mistaken identity. Some attacks were because the ships were sailing in an Allied Convoy. Some attacks were because the ships were armed and Germany considered them as auxiliary warships. Some attacks were because the British were beleived to be flying neutral flags on their ships to trick the U-Boats. Some attacks were because the neutral was in Allied waters and the U-Boat Captain felt the ship was trading with the allies.
they threw you overboard.
Throw ropes with hooks attached to ships or even castles to scale the walls or sides of the ships.
robs phone # is 913.660.6775
A person who robs is called a "Robber".
. . . submarine attacks upon merchant ships .
U-Boat
A pirate most probably. Or possibly a buccaneer.
He paid tribute to the Barbary States.
attacks on U.S. and British ships