Operations information for U-604
04.08.1942 - 08.09.1942
First Sailing - active patrol
U-604 left Kiel under the command of Horst Höltring on 4th Aug 1942 and arrived at return on 8th Sep 1942 after five weeks.
Horst Höltring hit one ship on this patrol.
•On 25th Aug 1942 he sank the Dutch 7,906 ton Abbekerk.
14.10.1942 - 05.11.1942
Second Sailing - active patrol
On the 14th Oct 1942, U-604 left Brest under the command of Horst Höltring and after just over three weeks arrived at return on 5th Nov 1942.
Horst Höltring hit three ships on this patrol and all of them were in convoy, all of them from convoy SL-125.
•On 27th Oct 1942 he sank the British 7,705 ton Anglo Mжrsk, sailing with convoy SL-125.
•On 30th Oct 1942 he sank the British 3,642 ton Baron Vernon, a member of convoy SL-125.
•On 30th Oct 1942 he sank the British 11,898 ton Prйsident Doumer, part of convoy SL-125.
26.11.1942 - 31.12.1942
Third Sailing - active patrol
U-604 departed under Horst Höltring from Brest on 26th Nov 1942 and arrived at return on 31st Dec 1942 after five weeks.
Horst Höltring hit one ship on this patrol from convoy MKF-3.
•On 2nd Dec 1942 he sank the American 7,057 ton Coamo, from convoy MKF-3.
08.02.1943 - 09.03.1943
Fourth Sailing - active patrol
U-604 left Brest under the command of Horst Höltring on 8th Feb 1943 and after just over four weeks arrived at return on 9th Mar 1943.
On 24th Feb 1943 in square BC 92, U-604 came under attack from an aircraft of RCAF 5 Squadron. U-604 was moderately damaged by the attack.
Horst Höltring hit one ship on this patrol from convoy ON-166.
•On 23rd Feb 1943 he sank the British 1,583 ton Stockport, sailing with convoy ON-166.
22.04.1943 - 26.04.1943
Fifth Sailing - active patrol
On the 22nd Apr 1943, U-604 left Brest under the command of Horst Höltring and arrived at return on 26th Apr 1943 after four days.
24.06.1943 - 11.08.1943
Sixth Sailing
U-604 departed under Horst Höltring from Brest on 24th Jun 1943 and after nearly seven weeks arrived at return on 11th Aug 1943.
On 27th Jun 1943 in square BE 98, U-604 came under attack from an unidentified aircraft.