Akte von Room 40 über U 54 (National Archives Kew, HW 7/3, pages 216 and 217):
Kaptlt. Freiherr von Bothmer till July 1917, then Kaptlt. Heeseler, then Kaptlt. Helmut von Ruckteschell. Was completed at Kiel about the beginning of May 1916, and joined the Kiel School for trials, proceeding to the North Sea on 1st July 1916. She was attached to the 2nd Half Flotilla.
4th July - 12th July 1916. North Sea patrol.
26th July - 4th August 1916. North Sea patrol. Returned owing to compass being out of order.
20th September - 1st October 1916. North Sea. Claims 11 trawlers.
13th October - 17th October 1916. North Sea. Returned with compass defects and loss of personnel through drowning.
23rd October - 14th November 1916. Cruise to Arctic. No sinkings.
29th January - 13th February 1917. Atlantic via Channel. Returned northabout. Sank 4 S.S., 1 sailing vessel (21,000 tons).
8th March - 3rd April 1917. Atlantic, northabout both ways. Claims 3 S.S., 1 sailing vessel (5,750 tons).
27th May - 23rd June 1917. ? Arctic. ? Sank 5 S.S., 3 sailing vessels, 1 motor vessel. Chased by H.M.S. GRIVE. Engaged by H.M.S. STEPHEN FURNESS.
14th July - 6th August 1917. To North and back.. Sphere of operations unknown. Claims 26,200 tons in July.
6th September - 7th October 1917. ? To north of Ireland and Bay of Biscay, northabout. Returned via Little Belt. Sank 1 S.S., 4 or 5 sailing vessels. Submarine was engaged by H.M.S. MEROPS, a submarine trap, on 27th September in Bay of Biscay. U-54 just managed to escape.
20th November - 22nd December 1917. To Bay of Biscay ? through Channel. Returned northabout and via Sound. Sank ? 3 sailing vessels.
? 11th February - 13th March 1918. Northabout ? to south of Ireland. Returned northabout and by Kattegat.
7th April - ? 20th May 1918. To N.W. and S.W. of Ireland from Bight by Fair Island. Back by Fair Island and Sound. Sank 4 S.S., 1 sailing vessel. Attacked 1 S.S. and 1 yacht.
? 8th July - 28th July 1918. To N.W. of Ireland, northabout. Concerned with UB-64 and UB-124 in sinking of S.S. JUSTICIA (U-54 fired first 2 torpedoes and mistook JUSTICIA for VATERLAND.) 57,000 tons are claimed for this cruise by Admiralty Staff.
18th September - 15th October 1918. Northabout to Channel approach. Sank 1 S.S.
24th November 1918. Surrendered at Harwich.