First patrol

U-432's first patrol was preceded by short 'hops' from Kiel in Germany to Horten Naval Base then Trondheim in Norway. Her first patrol proper began with her departure from Trondheim on 25 August 1941 and headed for the Atlantic Ocean via the gap between Iceland and the Faroe Islands.

The boat sank the Winterwijk on 10 September east of Greenland. She went on to sink the Stargad close by on the same date. The next day she sank the Garm northeast of the previous successes.

She docked at Brest in occupied France on 19 September.

Second and third patrols

On her second foray, she sank the Ulea on 28 October 1941 east-northeast of the Azores. She finished the patrol in St. Nazaire on 2 November 1941.

The boat's third sortie commenced with her departure from St. Nazaire on 10 December 1941. This was not only the shortest patrol of her career but the only time she returned to France, (this time to La Pallice where she would be based for the rest of her time), without success, on the 23rd.

Fourth patrol

Her fourth patrol was carried out on the eastern seaboard of Canada and the United States, where she sank a number of ships, including the-then neutral Brazilian vessels Buarque and the Olinda on 15 and 18 February 1942 respectively. She also sent the Miraflores and the Azolea City to the bottom on the 19th and 21st.

Fifth patrol

U-432 had departed La Pallice on 30 April 1942. On 2 May, she was slightly damaged in an air attack on 2 May west of the Bay of Biscay. She returned to her earlier hunting grounds across the Atlantic where she sank ships such as the Zurichmoor (on the 23rd) and the Malayan Prince on 9 June.

On 30 May, she torpedoed and sank the "Liverpool Packet" off the south-eastern tip of Nova Scotia. Of her 21 crew, two were killed when the torpedo struck. U-432 approached the 19 survivors, who had taken to lifeboats, and Schultze gave them directions to the nearest land. After 20 hours rowing, they succeeded in reaching Seal Island, off Cape Sable, Nova Scotia.^[4]

Sixth patrol

The submarine encountered some resistance when she came across the Pennmar off Cape Farewell (Greenland) on 24 September 1942. A torpedo fired from the starboard quarter was avoided by evasive action. On surfacing, the U-boat was engaged by Pennmar's 4 in gun. U-432 submerged again and fired a spread of four torpedoes, one of which hit and sank the American ship.

Seventh patrol

For her seventh effort, the boat headed towards Africa. She sank the Poitou off Morocco on 17 December 1942.

Eighth patrol and loss

U-432 sank HMS Harvester on 11 March 1943 after the British destroyer was badly damaged while ramming U-444. The French corvette Aconit came to Harvester's assistance. She depth charged and sank the U-boat in mid-Atlantic.

Twenty-six men went down with U-432; there were 20 survivors.

Wolfpacks

U-432 took part in seven wolfpacks, namely:

• Markgraf (28 August – 14 September 1941)
• Reissewolf (21 – 28 October 1941)
• Pfadfinder (21 – 27 May 1942)
• Lohs (23 August – 22 September 1942)
• Sturmbock (23 – 26 February 1943)
• Wildfang (26 February – 5 March 1943)
• Westmark (6 – 11 March 1943)