Books about submarine warfare on the Law of the prize April 1915-February 1917

[siono]

Hello. Can you recommend a book about underwater warfare on the Law of the prize from April 1915 until the beginning of unrestricted submarine warfare. I recently read a book about Gayer German U boat. And it says, after the U 20 sank the Lusitania, German submarines were shackled with all sorts of regulations and restrictions. I will give a few examples from the book Gayer. Here is what he wrote: U 33 captured one ship as a prize, it was also examined about twelve neutral vessels released by virtue of operating instructions. It was obvious then that these ships will serve the enemy, and therefore their destruction would bring only benefits submarine blockade. Meanwhile, the share of nearly every boat such inspections had a very large number!
Or here's another example: U 6 resulted in two prizes on July 24, before examining the Skagerrak, and between the Firth of Forth 41 ships! Of these, 21 steamer. From all of this, according to the instruction of the then could only sink the 9 sailing ships and one steamer.
And a third example: U 25, she operated off the coast of Norway and on the line Arkhangelsk Britain. She sank one Swedish and four Norwegian ship, Norwegian barque and three Norwegian ships to jettison part of the cargo. In addition it examined eleven ships were released on the basis of operating instructions.
I'm interested in the name and tonnage of these neutral merchant vessels which have been inspected and released between April 1915 and February 1917. Maybe there's a book in German, which has a name and tonnage of neutral merchant vessels which have been inspected and released for the period from April 1915 and by February 1917?
I hope somebody can recommend me a great book on the subject. Thank you.

[siono]

Sagen Sie mir bitte die Schiffs-Zeitschriften U-Boote U-6, U-25, U-33, U 24 und U-32 (März 1916) gelagert in Freiburg? Helfen Sie bitte. Vielen Dank im Voraus

[bodrog]

I think Schröder is a good introduction to the subject...

Joachim Schröder: Die U-Boote des Kaisers. Bonn: Bernard&Graefe 2003

He has corrected some statements from that period. In particular the statements of the commanding admirals and the resistance of the Reich government (Bethmann-Hollweg)  towards the unrestricted submarine warfare.