This dates from the same era as the Torpedo Testing Station at Arrochar. It is, basically, a giant tank of water which was used to test the launching, running and possibly impact of torpedoes.
The tank itself is imposingly massive, with gantries and cranes at one end to lift up the test torpedoes. The other side contained labs.
Inside, it’s been stripped, and is now used for training.
Up some stairs, though, and you come to the viewing galleries – one wall of the tank is reinforced glass – it’s Scotland’s biggest fishtank.
Back outside, and up some rusty stairs to the top of the tank. There’s a launching cradle for the torpedoes, and what I think is an impact target – it’s got a massive hydraulic ram.
After this, it was back down and out, pausing for one last look.