Just had this reply.
//I have asked around several people, including our Head of Heritage Engineering who oversees the Ropery, and I am afraid we have drawn a blank on this one, we really don’t have a clue what your mystery object is I’m afraid.
If you do find out what it is please could you let us know? I have several rather confused researchers at this end!
Kind regards
Claire McQuillan
Archive and Collections Care Officer
Chatham Historic Dockyard Trust
1st Floor North, Fitted Rigging House, Anchor Wharf, The Historic Dockyard Chatham, Kent ME4 4TZ//
We're still no wiser:-(