Liam,

I am working through both the WWI U-boats losses and the ships sunk by U-boats during the war, and the cases of Keeper and UC 66 are very interesting and let's just say "under review."

In recent years, serious doubts have been raised as to whether UC 66 really was sunk on June 12, 1917. The problem is one of patrol length. UC 66 was an UCII class boat operating from Flanders. Of 140 or so patrols by Flanders-based UCII through Dover to the English Channel, Irish Sea, or Bay or Biscay most patrol only lasted 12 to 17 days. The record patrol is 20 days. UC 66 sailed on May 22, 1917. If she were sunk on June 12th, that would have been on her 21st day at sea. This attack happened off the Lizard, so she would not have been home before June 15th, her 24th day at sea.

At this point I am aware of seven unidentified UCII wrecks against a population of 9 or 10 missing boats or boats with suspect loss causes (like UC 66). It is quite possible that UC 66 will be identified elsewhere.

As for the Keeper, here's the little we know: the unarmed 572 grt steamer sailed on June 9 from Belfast for Limerick with a cargo of wheat. She did not arrive at Limerick. Keeper was built in 1906 and owned by J. Bannatyne & Sons Limited of Limerick. The Royal Navy presumed that she was torpedoed and sunk in the Irish Channel on the 10th or later. The German official history, with I am assuming no other likely candidate for an Irish Sea sinking, assigns credit to UC 66. Of course, there were no survivors from UC 66 or Keeper, so that is really just a guess.

It appears this analysis missed something critical though. It is not obvious that Keeper would have sailed through the Irish Sea to get from Belfast to Limerick. She could have sailed along the Atlantic coast instead. Indeed, that is exactly what "Lloyd's War Losses" suggests: it notes that Keeper passed Aranmore on June 10th. Aranmore is, of course, an island just off the coast in County Donegal! This alone means that UC 66 did not sink Keeper, as UC 66 was assigned to the Bristol Channel and Irish south coast.

As a practical matter, Keeper need not have been torpedoed or even sunk by a German submarine. She could have been a marine casualty. Even if sunk by a German submarine, Keeper was certainly small enough to have been stopped and scuttled or sunk by gunfire from a U-boat. In that case, the crew would have taken to the lifeboats, which unfortunately did not reach land. A mine might also be possible.

Best wishes,

Michael