The Type U 66 submarines were originally constructed for Austro-Hungary as the U-7 class, but were sold to Germany at the start of WWI.
Coastal attack torpedo U-boats were smaller craft intended for operation closer to land.
Coastal minelaying U-boats were smaller vessels intended to mine enemy harbors and approaches.
Ten of these (UC-80 to UC-89) were broken up at yard At the outbreak of World War I Germany took charge of a number of submarines under construction in German shipyards for other countries.
In the World War II era, Germany commissioned some 1,250 U-boats into the Kriegsmarine.
The Type XI was a planned artillery boat, armed with four 128-mm guns in two twin turrets along with an Arado Ar 231 floatplane.