21st July 2020:

A team from OA North recently visited the remote Fort Clonque on Alderney in the Channel Islands to carry out a survey that proved to be anything but routine

Fort Clonque is located on a small rocky peninsular, which at high tide is separated from Alderney, so effectively is an island cut-off from an island. The fort was built in the mid-19th century, but after a short-lived military career became a private residence. It returned to military service during the Second World War when it, along with the rest of the island, was occupied by the Germans. After the war, the fort was again a private residence. It was sold to the Landmark Trust in 1966 and, following extensive conservation works, became a unique and very popular holiday home.

The survey, funded by the Landmark Trust, was to be an extensive one, with plans for a laser scan of the interior and exterior of the building, rectified elevations, and a drone survey, all to be completed in two days. This was no mean feat even for an ordinary building, and Fort Clonque is certainly no ordinary building.

The fort stands upon an irregular broken mass of granite, with a barrack block, gun batteries, a Second World War gun bunker, officers’ quarters, guard towers, artillery magazines and a curtain wall, set on two precipitous outcrops. What is more, the fort is accessed via a narrow causeway that is submerged by the sea twice a day.

Carefully timing to arrive at low tide, the team established a base in the former barracks block and began work immediately, scanning as much of the fort as possible. Unfortunately, a ferocious storm before the team’s arrival had damaged the services connecting the fort to the island, leaving the fort without light, power or heating. Luckily, a generator had been provided, giving the team lighting and a handful of sockets to charge the survey kit. The survey was undoubtedly challenging even with our hand-held scanner, as much of the external parts of the fort could only be surveyed at low tide and some parts were not accessible even then.


Surveying Fort Clonque at low tide


After two busy days, the survey was complete. But that was not the end of the adventure, as a thick sea mist delayed the team’s flight home. Fortunately, the fog cleared as quickly as it had descended, allowing the team to head home, ending one of the more unusual surveys that OA North has embarked on.


OA North's digital model of Fort Clonque