Army Coastal Artillery Range finding Positions were reinforced field-type, split-level constructions, although windmills and even Gorey castle was adapted for this role. The Fortress Engineers' construction map dated July 1943 shows these positions designated by the letter M for Mefistelle (Range-finding position). 


Equipment of the Observation Posts
Sketch of the terrain in which special points are named, and circle and distance to these Points
A board at each observation set with the co-ordinates to the set, fixed numbers to a near and distance fixed point, and to the beacon lights
Direction indicator with notch and bead sights to aiming points at sea in the observation area, with hoards for horizontal angle and distance
Map of Jersey 1:25000 with grid, entered observation area with grid and aiming points (sea and land), as far as they are in the region of the observation post
Sketch showing-, the nearest units and infantry strongpoints, including searchlights with a radius of act
Log with reporting instructions
Ten rules for the operator
Identification charts showing types of ships
Boards for passwords, signs of recognition, call and reply letter, emergency signals
Interpretation board for the different beacon signals
Board for determining the distance, with the aid of a bubble (for high and low tides & changing tides) 
Combat instructions
Duty instructions for the observation post
Sketch showing the different telephone cables
Board warning against mines
Operating instructions for flamethrowers with circuit diagrams
1 stereo telescope (aiming circle) with circuit diagram
A clock for the observation post or a military watch
1 pair of binoculars for each observer
1 torch for each observer
1 emergency light for each observer
1 container with petrol and matches in order to destroy secret documents
Chest with foodstuffs with a list of contents, with differing allowances already divided, a list for the control
A chest containing ammunition for the observation position
1 Flare pistol with cartridges 
1 set of ground panels
1 first aid kit
rifle rack and shelf for steel helmets and respirators