What is this building in portsmouth harbour?

[reallycoliholic]

How do they get to the bottom? Dive down or use an airlock sort of thingy?

 

[Baltika_no_9]

There were compartments on the side of the tank at 30, 60 and 100 feet. Initially drained these were then flooded and the door into the tank opened.

I can't remember how many ascents from each depth we did but I think it was 2 from 30' and 60' then at least one from 100'. One of the ascents was in an inflatable suit. It is over 50 years since I did it!

Edit: I now see Captainsensible's earlier post (#9) with more information, sorry

 

[lustyd]

How do they get to the bottom? Dive down or use an airlock sort of thingy?

The public went in from the top. 11th floor if memory serves (was 20 years ago though). I was always a bit sad that I wasn’t allowed to try from the bottom! Probably for the best though

 

[Martin_J]

There's quite a comprehensive account of how it's used, with photos, at the ScubaDiverMag website... (once you've scrolled past the first advert)

Goodbye to Gosport's iconic SETT