Disappearing Gun

[Ethelred the Almost Ready]

I presume these photos belong here.  Please move to another board if appropriate.

While on holiday we visited the Northern Royal Albatross colony near Dunedin, New Zealand.  Part of the tour there included visiting the 1886 Armstrong disappearing gun from the time of the Russian Scare. 
Although the British Empire was committed to defend it's territories and shipping routes, it was the responsibility of the colonies to provide their own harbour defences.  Fort Taiaroa was originally a Maori pa, then became the home of the Dunedin harbour defences and is now home to an albatross colony (clearing the land of the tress and scrub made the area suitable for these massive birds to land).

I am aware you can probably get better pictures of the gun elsewhere, but there are a few pictures here that I hope might be of interest.


Model of a 64 pounder muzzle loaded gun - one of the other batteries at the fort.


As the gun was raised and fired at the last moment the gun was rotatate under ground to the correct bearing.  The sign also reminds the gunners of the lighthouse that potentially stands in the way.



The gun itself showing the hand pump that was needed to generate enough hydropneumatic pressure to raise the gun.  Once fired, the recoil acted to repressurise the system so further pumping was not required.  Random tourist in the background.



The firing sequence.



A map of all the battery positions



Inside the observation post.



I can post more if there is interest.

[fred]

Cool photos. What makes it a “disappearing” gun?

[SteveBurt]

It only pops up to fire, then goes back down to be reloaded

[fred]

Sounds very clever. From a bit of googling, I’m still struggling to understand quite how it works.

Is there a metal roof that can be opened?
Does the whole gun platform move up to fire?
Or is it that the barrel and trunnions (bits that support the barrel) elevate up?

[vtsaogames]

The photo just above the "load and fire" instructions shows the gun on a olive drab scissors mount. It is carnked up when loaded. The recoil brings it back down again.