The mystery of the missing keepers at the Flannan Isles Lighthouse

The Flannan Isles, off the coast of northwestern Scotland and named after an Irish priest called St. Flannan, have been the subject of a mystery lasted over 100 years.
On December 15th, 1900 a boat called Hesperus set sail for the island of Eilean Mor, one of the seven islets (also known as the “Seven Hunters”) of the Flannan Isles.
Captain James Harvey was tasked with delivering a relief lighthouse keeper as part of a regular rotation. The journey was delayed a few days by bad weather, and when Harvey and his crew finally arrived, it was clear that something was awry. None of the normal preparations at the landing dock had been made, the flagstaff was bare, and none of the keepers came to greet the Hesperus. The keepers, as it turned out, weren’t on the island at all, but not only: all three of them had vanished.
Eilean Mor had its peculiarities: the island’s only permanent residents were sheep, and herders referred to it as “the other country,” believing it to be a place “haunted” by something paranormal. And in fact, the island had long elicited a sort of fearful reverence in its visitors. The main draw to the remote location was a chapel built in the 7th century by St. Flannan himself. Even those who never prayed were saw to do it, on the island.

What the Hesperus crew did find at the lighthouse was a set of curious clues. The replacement keeper, Joseph Moore, was the first to investigate, and reported, as he ascended the cliff toward the newly constructed lighthouse, that inside the kitchen table there were plates of meat, potatoes, and pickles. The clock was stopped, and there was an overturned chair nearby. The beds were tumbled, as if they men had just got up, the washing-up done, cold ashes in the grate. The lamp was ready for lighting, and two of the three oilskin coats belonging to Thomas Marshall, James Ducat, and Donald McArthur were gone. Which meant one of the men had gone out without his protective weather gear on, something that would have been virtually unprecedented. In addition, the gate and door were firmly shut.
These clues only led to more questions. Why would one of the keepers have gone out without his coat, and for that matter, why would all three have left together at all when the rules laid down by the Northern Lighthouse Board forbade it? Someone needed to man the post at all times, so something unusual must have drawn them out.
When Joseph Moore returned with his report, Harvey had the island searched. The hunt came up empty. The captain then sent a telegram to the mainland:

“A dreadful accident has happened at Flannans. The three keepers, Ducat, Marshall and the occasional have disappeared from the island. On our arrival there this afternoon no sign of life was to be seen on the Island.

Fired a rocket but, as no response was made, managed to land Moore, who went up to the Station but found no Keepers there. The clocks were stopped and other signs indicated that the accident must have happened about a week ago. Poor fellows they must been blown over the cliffs or drowned trying to secure a crane or something like that.

Night coming on, we could not wait to make something as to their fate.

I have left Moore, MacDonald, Buoymaster and two Seamen on the island to keep the light burning until you make other arrangements. Will not return to Oban until I hear from you. I have repeated this wire to Muirhead in case you are not at home. I will remain at the telegraph office tonight until it closes, if you wish to wire me.”

When authorities investigated the matter they found a logbook with some unusual entries. On December 12, an entry from Marshall described “severe winds the likes of which I have never seen before in twenty years.”
He wrote that Ducat had been quiet and McArthur had been crying, which would have been odd behavior for a man with a reputation as a tough and experienced seafarer. The next day, Marshall reported more storm details and wrote that all three of them had been praying. Another odd bit of behavior from well-seasoned keepers in a brand-new, presumably safe lighthouse. On 14 December there was no entry in the log. The final entry was made on a slate, which (under normal circumstances) would have been transferred to the logbook proper later on:
“December 15. 1pm. Storm ended, sea calm. God is over all”.
Strangest of all, there were no reported storms in the area on December 12th, 13, or 14. All should have been calm up until December 17.

Of course, speculation ran wild. Was it something supernatural? Sea creatures? A case of madness and murder? A government operation? Foreign spies? Theories over the years claim the men were killed by pirates, eaten by sea monsters and even kidnapped by aliens. There is much controversy about the logbook and many believe it was faked.
No one knows what happened to these three men. Authorities chalked it up to a freak accident that caused all three of them to have been swept away by the sea.
Robert Muirhead, superintendent of the Commissioners of Northern Lights, wrote in his official report:

“I am of the opinion that the most likely explanation of this disappearance of the men is that they had all gone down on the afternoon of Saturday, 15 December to the proximity of the West landing, to secure the box with the mooring ropes, etc and that an unexpectedly large roller had come up on the island, and a large body of water going up higher than where they were and coming down upon them had swept them away with resistless force.
I visited them as lately as 7th December and have the melancholy recollection that I was the last person to shake hands with them and bid them adieu”.

While this (or something similar) seems possible, the explanation left considerable room for doubt. The lack of bodies, supposedly calm conditions, and sheer experience of the expert lighthouse keepers, for example. In the years following, other keepers claimed to hear voices in the salty air screaming out the names of Thomas Marshall, James Ducat, and Donald McArthur.
In “Mysterious Celtic Mythology in American Folklore”, author Bob Curran writes: “For many local people, there was little doubt that they had been spirited into the otherworld.”