Secret Scotland

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World record echo heard in Inchindown fuel depot tank

A new World record has been set inside one of the tanks of the massive underground wartime fuel storage depot constructed at Inchindown, near Invergordon, for the longest echo in a man-made structure.

The Inchindown Fuel Depot lies in the hills some four miles north of Invergordon, and was constructed in the period 1939-1942, during World War II, as a bombproof fuel oil store for the Royal Navy, and was connected by pipeline to the Royal Navy dockyard, fuel depot, and port facility at Invergordon. The depot was also referred to as Inchindoun, and the Inchindown Admiralty Underground Storage Depot.

Inchindown Portal

Entrance Portal © Mike Ross –

Reports indicate that five such stores were constructed around the country at the time: Inchindown, Copenacre, Hartham Park, Monk’s Park and Portsdown. Had the German Navy blockaded Britain’s ports, these depots would have been called on to provide fuel for the Royal Navy.

Salford University acoustic engineer Prof Trevor Cox recorded a shot fired from a pistol loaded with blanks inside Inchindown tunnels near Invergordon.

The time for the reverberation to end was 112 seconds.

That beat the 1970 Guinness World Records time of 15 seconds set in Hamilton Mausoleum in Lanarkshire.

Allan Kilpatrick, of the Royal Commission on the Ancient and Historical Monuments of Scotland (RCAHMS) and an expert on Inchindown, fired the pistol, loaded with blanks, about a third of the way into one of the storage tanks.

Prof Cox recorded the response picked up by the microphones about a third of the way from the far end.

Via New world record for longest echo set near Invergordon

Listen to (at least part of) the echo:

Below is a view along one of the access tunnels leading to the tank where the record was made:

Inchindown Tunnel

Inchindown Tunnel © Mike Ross –

There are no access doors or hatches provided for any of the tanks, so the only way in to or out of them is via the pipework.

Behind these access ports the tanks are immense, and held almost 32 million gallons of fuel. The five main tanks measure some 9 m wide by 237 m long and 13.5 m high,and each could accommodate 16 double decker-buses end to end into – if you could fit them through the ports! A sixth reserve tanks, a little smaller than the main tanks made up the total.

Last believed to have been filled during the Falklands War, the type of heavy fuel oil they once stored is no longer used, and the tanks have been cleaned to remove any residual material and related potential hazards.

Inchindown Pipes

Inchindown Pipes © Mike Ross –


19/01/2014 Posted by | Civilian, World War II | , , , | Leave a comment


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