ROYAL NAVY HARBOUR DEFENCES - OBAN
If you have any feedback please email me:
Dr Richard Walding
Research Fellow - School of Science
|Photo of Ganavan headland taken in 1945. During the war the area was surrounded by a barbed-wire fence and the huts were hidden in the bush and not visible from the road or the signal station. Today, the area is grassy and the remains are quite visible.|
A BRIEF HISTORY
In the 1930s, Admiralty policy was that important harbours should be progressively defended by fixed anti-submarine defences consisting of one or more indicator loops. Loops took a fair while to survey, plan and lay and this lead time was thought necessary. If hostilities arose, the plan was that the Royal Navy would then lay harbour defence Asdics (HDAs) and controlled mines. However, it became apparent that the cost of repairing and maintaining existing loops was becoming prohibitive so the laying of more loops had to wait until conflict occurred. By 1938, the possibility of conflict with Germany was most likely so loop laying was stepped up. By 24th August 1938, four ports were protected (Portsmouth, Portland, Plymouth and Firth of Forth) with the Straits of Dover being added in Autumn 1939. Two others - at Penang and Singapore - were also under RN control. Others, such as Falmouth, Berehaven, Queenstown, St George's Channel, North Channel and Tynemouth were planned for 1940-41 as well as overseas loops at Singapore, Alexandria and Malta. No loop station was planned for Oban Bay.
In early 1940, with the imminent fall of France and the threat of invasion, many emergency coast batteries and harbour defence stations were constructed. On the 6th February 1940, the Admiralty decided that Oban Bay should be used as an additional naval base to the Kyle of Lochalsh, which was the gathering point for convoy ships but could not provide the facilities that Oban could. The role of the navy was to protect and administer the harbour and surrounding waters, to accommodate merchant ships in the anchorage and organise the sailing of the convoys to join with larger convoys to the USA, Russia and elsewhere. The naval detachment at Oban grew as France fell and more and more convoys were rerouted from the English Channel and South Ireland to the waters between Northern Island and Scotland. The loss of the Irish ports was greatly felt.
The USN set up
about a dozen 'loop receiving stations'
on the East Coast, Panama and San Francisco. The Royal Australian
Navy installed indicator loops at a dozen sites around Australia and Port
Moresby from 1939 to 1942. Loops were also installed by the RNZN at Auckland Harbour
in 1942, and by the RCN at Saint John, Digby and Prince Rupert (Canada) from
GERMAN RECONNAISSANCE PHOTO
THE BUILDINGS TODAY
LOOP CABLE LOCATIONS
There were two loops at Oban Bay. Loop 1 went from Ganavan headland (just a little bit
north of Maiden Island) across to the beach to Gorten just north of Loch Dun on the
Island of Mull. Loop 2 stretched from Craignure (on Mull) across the Sound of
Mull to the tip of the Morven district (Rubha an Ridire).
This Luftwaffe reconnaissance photo of Kerrera Sound was taken in December
1940. It shows the naval base at Oban and aircraft of 210 Squadron RAF at their
A panoramic view of the Ganavan headland - looking towards the Isle of Mull. The harbour defence huts are on the right of the photo.
The diagram above left shows the relative location of the concrete huts and
slabs. Only buildings A and E remain standing today. The photo on the
right shows the huts as they were in 1945.
Photo 1 - A full view of the headland overlooking Oban Bay. Building
"A" - the Loop Control Hut - is on the left and building
"E" on the right. The remains of building "F" are in the
foreground. The Isle of Mull is in the background to the left and Lismore
Island is to the right.
Photo 4 - Building "E", viewed from the South East.Three rooms: two are 2270 mm x 2070 mm, and the third
is 3670 mm x 3670 mm.
Photo 5 - Building "E" viewed from the top of the steps
that lead East from the Loop Control Hut ("A").
Photo 13 - The Loop Control Hut ("A") viewed from the West.Two rooms: 2070 mm x 3860 mm; 2480 mm x 3860 mm.
Photo 15 - The Loop Control Hut ("A") viewed from the East, seaward
Photo 16 - Loop Hut "A" viewed from the seaward side.
The white building on the hill behind it is the Naval Signal Station.
The floorplan of the Loop Control Hut (Building "A"). Walls are
double thickness brick (230 mm wide) and the windows are 1200 mm wide and 900
mm deep. On the right there is a small hole in the wall through which cable
(probably power) runs. Above it are four pieces of dowel embedded in the wall to which some
equipment was affixed.
The rear wall of the right hand side room (the Indicator Loop Room) of the Loop
Control Hut as it is today. The rear and right-side windows are now open to the
elements. A doorway leading to the left room (Binocular Room) can be made out.
This photo of a naval rating in the Indicator Loop room of the Control Hut
was taken during WW2. It is the same room as shown directly above. The rear and
side observation windows and frames are clearly discernable although the
equipment being monitored by the rating is not clear. The wooden door, door
jamb and cement-rendered brick is visible.
Photo 20 - Building "E" viewed from the rear.
Building "E" - floorplan. The walls are double layer bricks about 230
mm wide. Because this is down in a bit of a hollow and has no view of the loop
area, it is suspected that this building may be a generator room or store.
GERMAN RECONNAISSANCE PHOTO
THE BUILDINGS TODAY
LOOP CABLE LOCATIONS
There were two loops at Oban Bay. Loop 1 went from Ganavan headland (just a little bit north of Maiden Island) across to the beach to Gorten just north of Loch Dun on the Island of Mull. Loop 2 stretched from Craignure (on Mull) across the Sound of Mull to the tip of the Morven district (Rubha an Ridire).
LOOP CABLE SAMPLES
Coming ashore at Gorten on Mull (see map above) are some cables that are most likely WW2 "tail" cables for the No. 1 Indicator Loop. The cables were photographed by Geoff Twibell. He describes them as follows: There are some six steel-sheathed cables in all, three of them having frayed down to the inner cores. One contains four rubber-covered cores - possibly "loop tails". Another contains a single, larger core. The remaining cable is post WW2 and contains four PVC insulated cores one red, one blue and two white.
|The six armoured cables at Gorten||Gorten shoreline with hut in background. Cables run up this rocky shore.|
|Probable Indicator Loop "Tail" cables||The telegraph hut - post WW2|
R.A.F. BASE AT GANAVAN SANDS
At Ganavan Sands beach (on the north side of the headland where the loop huts were located) there was an RAF flying-boat base where maintenance and training was carried out. A hanger and several engineering sheds were built there to house the operations.
|Number 302 Ferry Training Unit based at Ganavan Sands||Ganavan Sands Caravan Park toda|
The photo above on the left shows the Number 302 Ferry Training Unit based at Ganavan Sands where they trained crews to fly their aircraft over long journeys to such destinations as Africa, Asia and even Australia. The photo on the right is of the Ganavan Sands Caravan Park today. Little remains of the RAF base, however, the steel runners of the hangar doors and the former generator shed still remain. The indicator loop huts were on the headland at the rear of the photo. RAF Base image taken from Paul Burns' RAF Oban web page.
OBAN - MINEFIELD CONTROL TOWER
There is a minefield control tower at Gallanach overlooking the Sound of Kerra; it lies on the hillside on the south side of a caravan park.
For more details, have a look at Nick Catford's photos and text on the Subterranea Britannica web site.
If you know of other WW2 indicator loop stations around the world, please contact me with some of the details so we can correspond.
I'm particularly interested in getting information from officers and ratings who worked in the loop stations or laid the loop cables. Also, many scientists were involved in the research at the Royal Navy's "Underwater Detection Establishment". Are you still out there?
* Note: The green radar screen referred to above was at the Radar Station not inside the Loop Hut. An indicator loop uses pen and ink to record a line on a continuous roll of paper about 8cm wide. The photo below was taken at the Pennyfuir Gates. The radar towers are visible in the background.