The story of the attack by U-47 at Scapa flow did not end on the fateful day in October 1939; as recently as September 2002, almost 63 years after the event, Prien and his boat were in the news again following the rather bizarre discovery of one its torpedoes by the Norwegian tanker MV Petrotrym. The following extract is taken from The Scottish Banner, a paper published in the United States for Scottish expatriates:
"TORPEDO" - Scapa Flow, Orkneys: An oil tanker recently had a narrow escape when it was nearly hit by a German torpedo - fired 63 years ago! The missile was one of four launched by submarine U-47 to scupper the battleship 'Royal Oak' in 1939 resulting in the loss of 833 lives.
Even though it failed to hit its target, the torpedo has lain on the seabed ever since, until it recently resurfaced in the dark waters of Scapa Flow and started to drift towards the 62,000 ton Norwegian tanker 'Petrotrym' , which was at anchor. Fortunately an attentive watchman noticed the barnacle-encrusted missile and raised the alarm in time.
The 15 foot torpedo was towed away by a tug to safe waters a mile away where it was detonated by a Royal Navy bomb disposal unit. Although its warhead was missing, the Navy said that it posed a genuine threat as it still contained its chamber of compressed gas.
(Thanks to Allan F. Cameron for submitting this article)
Following the removal of the torpedo to Scapa Pier on 9 September, Captain Nigel Mills, the Director of Orkney Island Council's Harbours Department, offered the following explanation for its sudden reappearance:
"It is difficult to state at this point exactly why this object decided to surface now. We did have an exceptionally low tide on Monday and it is possible that this disturbed the torpedo and allowed it to surface. Compressed air within a chamber inside the torpedo can force them to the surface in the way this one apparently did".
(Details from the Orkney Islands Council web site)
While the surfacing of the torpedo can be explained in purely scientific terms, its sudden reappearance in Scapa Flow over sixty years afterwards was remarkable. Might it indeed have been Prien's ghost, shouting defiantly from the depths?