SM UC-45 was a German Type UC II minelaying submarine or U-boat in the German Imperial Navy () during World War I. The U-boat was ordered on 20 November 1915 and was launched on 20 October 1916. She was commissioned into the German Imperial Navy on 18 November 1916 as SM UC-45. In five patrols UC-45 was credited with sinking 12 ships, either by torpedo or by mines laid. UC-45 sank in a diving accident on 17 September 1917 in the North Sea. The German salvage vessel raised the wreck and UC-45 re-entered service on 24 October 1918. She was surrendered on 24 November 1918 and broken up at Preston in 1919âÂÂ20.
A Type UC II submarine, UC-45 had a displacement of when at the surface and while submerged. She had a length overall of , a beam of , and a draught of . The submarine was powered by two six-cylinder four-stroke diesel engines each producing (a total of ), two electric motors producing , and two propeller shafts. She had a dive time of 48 seconds and was capable of operating at a depth of .
The submarine had a maximum surface speed of and a submerged speed of . When submerged, she could operate for at ; when surfaced, she could travel at . UC-45 was fitted with six mine tubes, eighteen UC 200 mines, three torpedo tubes (one on the stern and two on the bow), seven torpedoes, and one Uk L/30 deck gun. Her complement was twenty-six crew members.