Thanks for all the additional information. I gather Prager's book is highly informative but hard to get hold of and available only in German. I wish I could get hold of a translation.
This is from http://www.deutschland-class.dk/deutschland_luetzow/deutschland_luetzow_operation_hist.html
and looks like a direct quote from the KTB and matches K & S.
From 1540, 10 April 1940 Lützow sailed for Kiel for repairs and to fit out for the still-scheduled Atlantic commerce-raiding operation. Along the fjord she made stops to pick up and set down various passengers before releasing her two escorts, Mowe and Kondor, to assist their sister vessel Albatros, aground and sinking near Søstrene, at 2200. On entering the Skagerrak, the cruiser found a northeast wind Force 4, Sea State 3, on a clear starry night with exceptional visibility. Lützow was soon steering 117° at 24 kt, Thiele remarking in the War Diary that, as British submarines were known to be stationed along the Swedish coast, he proposed to give them ample sea room by "standing off a little to the west at high speed".
At 0020, 11 April 1940 Lützow passed the Skagen-Paternoster line on course 138°.
At 0120, 11 April 1940 Radar reports object astern at 6°, 1,5 km.
At 0126, 11 April 1940 Turned to port at 1,15 km. Nothing seen, no further radar contacts, starboard rudder to original bearing to get us through Skagen Narrows as soon as possible.
At 0129, 11 April 1940 Lützow still turning. Enormous shock astern. Torpedo track reported acute angle port side. Assume submarine attack.
At 0130, 11 April 1940 Lützow still turning, rudder jammed starboard 20°. Compartment 11 does not answer or obey engine telegraph. Reported to bridge, "Manual rudder room cannot be manned. Stern flooding, ship listing to port and gradually settling." I intend to steer by propellers, port astern, starboard forward, at 18 kt.
HM Submarine Spearfish had fired a fan of her last four torpedoes at Lutzow and obtained a single hit astern, knocking off both screws and the rudder and breaking the stern.
At 0220, 11 April 1940 0220: Signal to Group East: "My position is 233°, 10 nautical miles off Skagen. Am unmanoeuvrable, flooding held, both screws lost. Lützow situation: ship drifting broadside to sea at 2 kt SW towards Skagen. I hope to find a lee and calm waters in Aalback Bay. As the ship is visible from afar, further submarine attacks are to be expected. Boats made ready for lowering, all crew members wearing lifejackets, all lower decks evacuated with exception of damage control personnel. "B" turret has jettisoned all ammunition to help lighten the stern. All Flak guns closed up, sharp anti-submarine watch set."
At 0318, 11 April 1940 Sent off ObltzS V. in the motor cutter to Skagen to request tugs and escort vessels.
0305 - 0337, 11 April 1940 Signals from Group East, "Torpedo-boats Luchs, Seeadler, Jaguar, Falke, Mowe and Kondor, 17th UJ Flotilla, 2nd E-boat Flotilla and UJ 172 on way to assist."
The enquiry must have been interesting if the 15,000m detect is correct! "So Kapitan, with a damaged ship (Drobak Narrows), no escorts and close to an area where enemy submarines had sunk three packed troop transports in a well escorted convoy you sailed straight up to an unidentified contact at night so so it could torpedo you killing 15 of your crew. Not to mention leaving your vessel at the mercy of that enemy, and denying the service of your ship for at least a year."
This source says the S-Anlage was installed 18th November 1940.
Is the radar detector installation the 12th June 1941 deployment or the 1942 deployment?
All the best