In the Waters of the Loch, we have Machan, an underwater hide built by Adrian Shine and used in the clear water of Loch Morar, the ‘other monster loch’, in 1974&5. Machan is the Hindi word for the hide from which you might shoot a tiger. This Machan was an underwater hide. Six sections, twenty fibreglass layers thick were bolted together by flanges.
To submerge, the observer let water into the two ballast tanks on either side of his seat. The two copper pipes at the front were for the hoses through which air was pumped down from a shore station and extracted. The two studs close by were for the telephone connection wires.
The cramped observer position limited observation periods to about two hours. To surface, he expelled a little water with just a few strokes of the ‘Stirrup Pump’ used to fight incendiary bombs during WWII. This double acting, low volume but high-pressure pump counteracted the external water pressure at depth. However, once level with the surface, the conventional high-volume low-pressure bilge pump was needed to quickly obtain working freeboard sufficient to open the hatch.
Because people reported large shapes moving close along the shore, the chamber was used to depths of 10m and baited to attract fish. The observer looked through the upward sloping plate glass windows towards the bright surface against which we hoped to see the entire silhouette of any large unusual animal.
In an extreme emergency, the observer could pull a lever at his feet, whereupon a small disc near the base of the sphere rotated to release a cage containing 1000lbs of rock ballast collected on site. Should even this fail, there would be no alternative to flooding the submersible to allow the hatch to be opened. The observer might then swim to the surface or drown in the usual way!
