SCAUR Hill has been a military district since the 1870s through the Second World War of 1939-45. The American Army occupied the site on the highest hill of Somerset Island for several years, from 1941 to 1943.

Two large guns mounted on railway carriages on tracks to nowhere sat there next to the large water catchment, waiting for the Germans to come over the horizon. The scene from the fort is the most stunning vista in western Bermuda.

The reefs off this coast extend some ten miles to the west and north, with many shallow areas that reflect the sunlight in many colours of the rainbow. At Scaur Hill Fort, the built military heritage combines with the natural environment to make a sightseeing adventure for all comers, as these assets do in the east at St. David's Battery.

The fort ditch cuts Somerset in two, though few going over Scaur Hill know that they pass over it, now infilled where once a wooden bridge existed. West of the Somerset Road, the ditch runs downhill to the waters of Ely's Harbour.

Rubble and trash had accumulated in an embayment nearby, but a recent gale gouged out some of this rubbish, revealing old motors and other goodies. Protruding from the exposed area was a piece of flotsam that looked like a large bomb or torpedo.

Asked to investigate, I thought of sending my brother Andrew in as cannon fodder but he declined, so we called the Bermuda Police Service. Members of the Explosive Ordnance Disposal Unit (EOD) came immediately and went to work on the mystery object.

The EOD determined that it was not a bomb or torpedo, but rather a buoy of a military nature. No one knew what the object was, so it was put on the front page of this newspaper and circulated to my colleagues of the Coast Defence Study Group in the United States, courtesy of Bermudaphile Terry McGovern.

Bermudian Colonel Sumner (Chip) Waters rang to say it was probably some type of float. Mackenzie J. Gregory in Australia confirmed it to be an "Oropesa Float", for minesweeping. Bermuda Maritime Museum benefactor Kenneth Kelly of New York kindly supplied data on minesweeping.

The float and the method of sweeping for mines were developed at the torpedo establishment, HMS Vernon, on a fishing trawler, Oropesa, towards the end of the Great War 1914-18. (Some may recall another Oropesa, a liner in service as a troopship when she was sunk by U-96 on January 16, 1941, with the loss of Bermudian Douglas W.H. Hutchings.)

In the earliest illustration in this article, a float of this type is being launched from a trawler, possibly in the 1920s. As a result of the experiments, the buoy and the method became know as the "Oropesa Float" and the "Oropesa Sweep". The picture of an Oropesa float being launched from the Australian Navy ship, HMAS Mildura, shows that it is very similar to that washed up on the shores of Ely's Harbour, which was found upside down and likely of 1940s vintage.

THE Oropesa float has three important components, all found on the Bermuda object. On the top was a bracket for a flagpole, so that the men on the ship could see where the mine-sweeping cable was. A single fin with side fins provided steerage at the rear of the float and a bracket slung underneath towards the front was the attachment for the sweep wire.

According to retired serviceman Mackenzie Gregory, who has the excellent AHOY naval web site

(www.ahoy.tk-jk.net): "Sweeping gear was normally used for the sweeping of contact mines, moored in shipping channels, set at different depths to make contact with the bottom of ships as they passed over them.

It consisted of an Oropesa Float, Otter and a Kite. The Oropesa float with the otter suspended underneath at a predetermined depth was streamed over the stern quarter of the ship by a serrated cable with a cutter attached near the otter end.

"On the inboard side of the ship, the kite was attached to the cable to control the depth of the cable between the ship and the otter.

"When the wire caught the mine's mooring cable, it cut through and the mine floated to the surface, to be sunk by rifle fire."

Minesweeping is a very dangerous occupation and many ships have been damaged or sunk in the attempts to remove such hazards to navigation in wartime.

Later on, ships were made of wood, so that the minesweeper itself did not set off the newer types of magnetic mines.

Like the Merchant Marine and other sectors of vital wartime services, minesweeping was an essential, if unglamorous, part of naval activity. New, hi-tech mines have increased the dangers of this service. Sometimes, dolphins have been used to detect mines on the sea floor without telltale mooring wires.

So beneath the buried object discovered at Ely's Harbour lies an important military subject on a vital naval service.

AFTER ascertaining it was empty, unfortunately the Oropesa Float disintegrated when an attempt was made to turn it over. This occurred as it was made of iron and had been sitting in the high tide zone for some years. That was a pity, for having floated into history once again, it would have been good to be able to preserve such an unusual gift from the sea for future generations.

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Dr. Edward Harris, MBE, JP, FSA, Bermudian, is the Executive Director of the Bermuda Maritime Museum. The views expressed here are his opinion and not necessarily those of the trustees or staff of the Museum. Comments can be sent to drharrislogic.bm, to PO Box MA 133, Sandys MABX, or by telephone at 734-1298.