At 21.08 hours on 30 Sep 1939 the neutral Gun (Master J.M. Persson) was stopped by U-3 about 30 miles northwest of Hanstholm. The master came aboard with the papers of the ship, which showed that she was carrying contraband. While the Germans interviewed the master, the vessel suddenly began moving and turned towards the U-boat. Warned by a similar behavior of Vendia earlier that day, U-3 evaded quickly and sent a boarding party of four men, led by WO Lt. Fraatz, aboard at 22.00 hours. Shortly thereafter the U-boat had to dive when a vessel was sighted heading for the stopped ship, this proved to be HMS Thistle (N 24) (LtCdr R.W. Stirling-Hamilton, RN) which was attacked with one G7a torpedo at 22.56 hours. The torpedo missed and the submarine dived shortly afterwards, although they were not aware of the attack. The submerged HMS Thistle passed under the stern of the steamer, not knowing that Germans were aboard and prepared the ship for scuttling. The submarine surfaced after one hour and left the area, encountering the lifeboat with the Swedish crew. They told them to return to their ship as she was still afloat, but in the meantime the seacocks had been opened and scuttling charges were placed. The boarding party left the Gun in one of her lifeboats and were picked up by the Danish steam merchant Dagmar along with the Swedish survivors. At 05.30 hours, U-3 stopped this steamer to take off the boarding party and then went to the drifting Gun to sink her by a torpedo at 09.10 hours.