PING PONG TARGET?

Any ideas. Where and what?

www.iwm.org.uk/collections/item/object/205444270

Ah, I see now the single PP ball 'floating'. The flexi pipes leading in are the LP air supply with the Sergeant operating a valve. So, a target to be shot at but the building type is strange. Timber framed, dirt floor with duckboards. Sandbags to contain shot.

If you follow the line of the (airlines ?) it appears that the sand bags may be to hold them in position when high pressure is applied and they start to flex about like a firefighters hose .The building appears to be open on the side facing the camera .The duckboards suggest to me however the possibility that the airlines might be water lines and the floor might get wet and slippy . you can make out what might be a pressure dial which might be air or water . Whilst not arguing with the floating ball target might it not float on a water fountain not an air fountain .Alternatively might there be a posssibility of the apparatus being for training in fire fighting or fuelling aircraft ?