Appearance: A likely non-issue/private purchase knife owned by a German soldier in WWII, later taken by an American who carved on the handle for posterity.
Analysis of the knife itself: It was made by C Lutters & Cie, a very old and prolific German firm that was an active supplier of cutlery goods during WWII. Black composition handles. Pins, liners and bail are all made of an unknown metal alloy that has badly corroded. I've never seen this material used on knives before, an especially poor choice for a knife that would be exposed to salt air, suggesting potential wartime production when more appropriate materials were not available.
Potential veracity of markings: It is not a stretch of the imagination that a young man joining the navy would buy himself such a knife. U-boat 858 was not commissioned until the latter part of 1943 and saw only three patrols. It was ordered to sail to the east coast of the United States to harass shipping, but never saw any combat and never damaged or sunk any ships before the end of the war arrived and her captain brought her in to port at Fort Miles, Delaware, USA to surrender. The ship was briefly used for publicity purposes by the US Navy before being sunk for torpedo practice. This makes it quite clear Americans would have access to items aboard the ship or surrendered by soldiers upon capture. The rather bland service record of the ship it purportedly came off of also makes it an unlikely target for a forger.
So there you have it, I believe this likely is what it seems to be. It's a beat up junker of a knife I paid very little for, but it was worth it for the history.
