Arran’s floating airstrip

Lily of Lamlash Bay

David Milloy

Did you know that a floating airstrip was once anchored off Lamlash? And, no, I don’t mean an aircraft carrier but an actual runway which not only floated but gently undulated as it rode on top of the waves.

The year was 1945 and war was still raging in the Pacific, where the allies were contemplating the daunting task of invading Japan. To help support fighter operations and take some of the pressure off their aircraft carriers, the Admiralty entertained the possibility of using unpowered floating airfields, which could be moved from place to place as required, either by being disassembled, moved by ship and reassembled, or by being towed.

Two types of floating airstrip were tested, one of which was codenamed ‘Lily’, presumably because it floated like a pond lily. The brainchild of R.M. Hamilton, Lily was based on his previous concept for a floating road, ‘Swiss Roll’, which had been tested with a view to using it to transport supplies from ships berthed at the artificial ‘Mulberry’ harbours used in the waters off Normandy in the months following D-Day.

Tested in Lamlash Bay, Lily was formed out of floating hexagonal units, each of which was six feet across and about 30 inches deep. These units were topped with steel plates and hinged together to form a runway. As tested at Lamlash, Lily was 520 feet long, 60 feet wide, weighed 5,000 tons, and was able to accommodate aircraft up to 9,000 pounds in weight. Arrester wires were fitted so that aircraft which had landed could be brought quickly and safely to a halt, and RATO (rocket-assisted take off) units, which shortened the length of runway a plane needed in order to become airborne, were also successfully tested.

Although Lily’s runway flexed up and down according to the movement of the waves, it was found to be safe for use in waves of up to 35 feet. Lily proved to be durable, too, with little maintenance being required during the nine months over which testing took place.

Had Operation Downfall, the invasion of Japan, gone ahead, it’s quite conceivable that floating airstrips such as Lily would have been pressed into use. As it was, however, the end of the war against Japan saw the concept of floating airfields largely shelved. It is, however, an idea which continues to attract interest, but although floating airfields have from time to time been constructed and tested, none are presently in operation.