German submarine U-603

German submarine U-603  was a Type VIIC U-boat built for Nazi Germany's Kriegsmarine for service during World War II. She was laid down on 27 February 1941 by Blohm & Voss, Hamburg as yard number 579, launched on 16 November 1941 and commissioned on 2 January 1942 under Kapitänleutnant Kurt Kölzer.

Design
German Type VIIC submarines were preceded by the shorter Type VIIB submarines. U-603 had a displacement of 769 t when at the surface and 871 t while submerged. She had a total length of 67.10 m, a pressure hull length of 50.50 m, a beam of 6.20 m, a height of 9.60 m, and a draught of 4.74 m. The submarine was powered by two Germaniawerft F46 four-stroke, six-cylinder supercharged diesel engines producing a total of 2800 to 3200 PS for use while surfaced, two Brown, Boveri & Cie GG UB 720/8 double-acting electric motors producing a total of 750 PS for use while submerged. She had two shafts and two 1.23 m propellers. The boat was capable of operating at depths of up to 230 m.

The submarine had a maximum surface speed of 17.7 kn and a maximum submerged speed of 7.6 kn. When submerged, the boat could operate for 80 nmi at 4 kn; when surfaced, she could travel 8500 nmi at 10 kn. U-603 was fitted with five 53.3 cm torpedo tubes (four fitted at the bow and one at the stern), fourteen torpedoes, one 8.8 cm SK C/35 naval gun, 220 rounds, and an anti-aircraft gun. The boat had a complement of between forty-four and sixty.

Service history
The boat's career began with training at 5th U-boat Flotilla on 2 January 1942, followed by active service on 1 December 1942 as part of the 1st Flotilla for the remainder of her service.

In five patrols she sank four merchant ships, for a total of.

On 4 December 1942 she was returning to base when she spotted a convoy and attacked by convoy escorts, but not before reporting to base and calling in support boats.

On 8 July 1943 she was attacked by a RAF Catalina with depth charges and slightly damaged.

On 13 October 1943 a Avenger from USS Card (CVE-11) dropped a FIDO Homing Torpedo but she successfully evaded the attack.

Convoy ON 166
On 21 February 1943, while operating against Convoy ON 166, she jointly attacked the Norwegian motor tanker Stigstad with GS U-332. U-332 hit her first with one torpedo, closely followed by two further torpedoes from U-603 which broke her back; sinking her in 15 minutes.

Two nights later she finished off the straggling Norwegian motor tanker Glittre with two torpedoes.

Convoy HX 237
Now under the command of Oberleutnant zur See Rudolf Baltz, U-603 attacked convoy HX 237 and successfully sank the Norwegian motor vessel Brand on 12 May 1943.

Wolf packs
U-603 took part in 13 wolfpacks, namely
 * Ritter (14–26 February 1943)
 * Burggraf (4–5 March 1943)
 * Raubgraf (7–20 March 1943)
 * Oder (17–19 May 1943)
 * Mosel (19–24 May 1943)
 * Trutz (1–16 June 1943)
 * Trutz 2 (16–29 June 1943)
 * Geier 1 (30 June – 14 July 1943)
 * Leuthen (15–24 September 1943)
 * Rossbach (24 September –9 October 1943)
 * Igel 2 (15–17 February 1944)
 * Hai 1 (17–22 February 1944)
 * Preussen (22 February – 1 March 1944)

Fate
U-603 was sunk on 1 March 1944 in the North Atlantic in position 48.91667°N, -26.16667°W, by depth charges from USS Bronstein (DE-189). All hands were lost.