Appendix D 1 -U-boats in the Second World War and their Fate

Two Differing German Accounts of the Surrender of U-570 on 27 Aug 1941 

The Rahmlow Case or the Story of U570 

(Taken from Internet websheet “Robikusch - U-Boot - Die Geschichte der Deutschen WK-II U-Boote” and translated by Sqn. Ldr. J.G. Owen-King)

27 Aug 1941 Midday 1300 hrs.

On this day an episode began which led to a fully functional U-boat all into the hands of the British which later in the war led to many other U-boats being involved.

U-570 was about 80 sea miles south of Iceland at a depth of 40m.  Kptlt. Hans-Joachim Rahmlow rose to periscope depth in order to look around.  The surface was turbulent, however, so that travelling at periscope depth was not possible.  So Kptlt. Rahmlow blew the tanks  and surfaced, and at that in a region well known to have regular British aircraft patrols.

Precisely at this moment a British Hudson bomber of Coastal Command flew overhead.  The observer spotted the U-boat immediately and signalled the pilot Major J.D. Thompson who, with screaming engines, at once dived and at a height of about 30m. released 4x115 Kg. depth charges.  The U-boat had hardly surfaced and the bridge watch emerged when the CDO in the conning tower bellowed the alarm.  The U-boat immediately submerged  - but too late.  The Hudson had dropped its depth charges precisely alongside the U-570 which had only reached a depth of 14m.

An ear-splitting detonation damaged the major part of the battery cells, the electric motors failed and all necessary instruments in the immediate vicinity were damaged.  The lights went out.  The boat started sinking, how deep no one can establish since the depth gauge was not clear.  Flooding was reported from the hull (this was later proved to be in error due to damaged instruments).  Flooding occurred in the bows due to leaks and the danger of chlorine gas was acute., through sea water mixing with battery acid.

The sinking accelerated and could not be brought under control with the ‘depth rudder’.  “All hands on the alert” bellowed the LI (Engineer Officer) and at the same time blew the bow (forward) tank 5.  The boat stopped still.

What happened next?

An experienced skipper such as Prien, Kretzschmer, Topp or others would have now installed some order in the boat and tried to halt its descent.

However Kptlt. Rahmlow (whose first operational trip this was as skipper) ‘blew’ all tanks immediately and the boat shot to the surface like a rubber ball.  The boat then moved uncontrolled through the foam.  But the British aircraft had now dropped all its depth charges and started to attack the helpless boat with machine gun fire.  Over 2000 rounds were fired.  Some of the U-570 crew had already come on deck and tried to get the 2 cm-flak working, but they failed and had to take shelter behind the conning tower.  About half a dozen of them were wounded.  The skipper then had red stars fired as a signal that they were unarmed.  The aircraft ceased firing immediately, circled round and radioed for reinforcements.  In the meantime the U-570 waved a white flag.  (Kptlt. Rahmlow said later that this had happened without his knowledge and he gave orders immediately for it to be withdrawn).

Meanwhile the Engineer Officer (LI) set some of the crew on to repairs and they even got the electrics back.  The lights went on, the pumps ran and the wireless worked.  Kptlt Rahmlow sent out a final radio message and then ordered the destruction of the wireless set.  He decided to scuttle the boat.  For this purpose he had all secret papers and the coding machine destroyed.

Late afternoon and it was already dark.   The Hudson was relieved by a Catalina flying boat from No. 209 Squadron and a British corvette appeared on the horizon - The Northern Chief.  Now was the time to scuttle and take advantage of the preparations made.

But things turned out very differently!

The British captain of the corvette sent a signal by Aldis lamp ordering a bright light to be displayed.  During the night everything that could be was destroyed on board the U-570: sea charts, artillery munitions, warheads and torpedoes.  Most of it was thrown overboard .  But why no scuttling?  The threat by the corvette to open fire at any attempt to scuttle and not rescue any survivors was taken seriously.  Next morning there was an inevitable increase in corvettes and destroyers preparing to take the U-boat into captivity.

Around 0800 hrs there was an obvious mistake made by the British.  An aircraft appeared and suddenly dropped depth charges at the U-570.  The British Admiralty later admitted it was pilot error.

A little later the destroyers Burwell and Windermere tried to pass a tow-line to the U-boat.  Three times they failed.  At 1030 hrs the U-boat lay with its bows dangerously deep in the water.  The Englishmen ordered Rahmlow to do something about this.  He signalled back however that the boat could not be stopped.  At this shots were suddenly fired from the destroyers and a further four men badly hit.  What did this mean?

At this point it must be said that statements made by the various participants were grossly contradictory in regard to the reaction aboard the U-570 to the shooting and the attack by the aircraft the previous day and this renewed shooting.  The wireless operator, Harry Ahlemann wrote in a letter to Paul Carell to the effect that Kaptlt. Rahmlow already hours beforehand had ordered a white bedsheet to be brought to the conning tower.  This bedsheet was then waved when the destroyer opened fire.  Kaptlt. Rahmlow, on return from POW camp, strenuously denied the story of the white flag and tried to justify his capitulation.

Meanwhile, below decks some of the crew decided to open the sea cocks and sink the boat.  Too late - armed Englishmen arrived from the Kingston Agate.  The crew were removed and at 1600 hrs the U-570 was towed to Iceland by the Northern Chief.  At last in British hands !!!

The first examination by the British revealed that the pressure hull was fully intact.

The most important results were :

·         One of the oil tanks had a hole.

·          Water was present in the bow section which had apparently been forced in through the outer hatches or the torpedo tubes.

·         Diesel engines and Electric motors worked, as did the compressors and the auxiliary machinery.

·         In the forward battery, 21 out of 62 cells were damaged as were 26 in the rear battery

·         The lights were working.

·         The wireless set had been rendered unserviceable by the crew.

·         The acoustic gear still worked.

After summing up the damages, a secret report from the British Admiralty stated that the boat, by and large, was still submersible and that a better bonded and experienced crew would have had no difficulty diving.  So why didn’t the U-570 dive after being attacked by the Hudson?

Peter E. Cremer, known as ‘Ali’, an experienced U-boat skipper in WWII  (U152, U333, U2519) writes as follows:   “Success or failure of a U-boat depends mainly on the competence of the captain.  Rahmlow was 32 years old.  Despite his 13 years service in the navy, he had only been a short time in the U-boat service as a commander.  His first U-boat was a training ship in the Baltic, and his second the U-570.  So he found himself and his ship on a first operational trip.  He needed the trust of his crew who, despite his strict set of rules, did not dislike him although he had carelessly surfaced without a preliminary periscope search and immediately crash-dived as the Hudson’s depth charges exploded.  A steadier and more resolute commander would have avoided panic and prevented the capture of his ship.  Rahmlow gave himself up.”