Next to the Handelsstörkreuzer the Kriegsmarine also sent its heavier surface units on commerce raiding, like the Admiral Graf Spee, Scharnhorst & Gneisenau and Bismarck & Prinz Eugen. How did these perform in their roles?
You have asked an excellent question. So the total breakdown of Allied merchant shipping lost in the war to Germany was the following:
70% - U-Boats
13.4% - Luftwaffe
6.5% - Sea Mines laid by U-Boats, drop by the commerce raiders, or parachuted by the Luftwaffe
6.1% - Sunk by German warships and converted merchant ships (commerce raiders)
4% - unknown causes, the merchant ship never sent off a radio transmission (the overwhelming majority lost to the U-Boats)
So the numerical breakdown is the following:
2.987 Allied merchant ships and warships sunk by the U-Boats
111 Allied merchant ships sunk by the 10 German Auxiliary Cruiser (armed commerce raiders)
48 Allied merchant ships were sunk by the warships of the Kreigsmarine
The problem the surface fleeet of the Kreigsmarine had in World War 2 was many. The Kreigsmarine only had 10 surface warships in the entire war capable of conducting combat operations in the Atlantic Ocean. These were the battleships Sharnhorst, Gneisenau, Bismark, and Tirpitz; the Panzersciffes Admiral Graf Spee, Admiral Scheer, and Deutschland (Lützow); and the heavy cruisers Admiral Hipper, Blücher, and Prinz Eugen. The light cruisers, destroyers, and torpedo boats (equivalent in size of the British corvettes) of the Kreigsmarine lacked the fuel capacity for operations in the Atlantic Ocean so the Kreigsmarine could not provide a screen of light warships to protect the heavy ships. Without a screen of light warships. the heavy ships of the Kreigsmarine could not attack well protected convoys becasue of the risk of being torpedoed by the escorting warships. Even though these ships are equipped with float planes, they can’t use them because a merchant ship would have automatically radio the Allied navies that they have spotted the German planes alerting the Allied navies that a German warship was in the area. And finally, Kreigsmarine surface fleet never fully recovered from the heavy losses they took during the conquest of Norway.