Nice lantern! Mine isn't a Perko but is put together the same way. Cptn Force is right... unscrews from the bottom. I didn't notice the pair of small rings near the bottom of the lamp to stabilize it if sending aloft.
I use mine as both a back-up for my electric
masthead anchor light and as a deck
placed on the bridge deck
inside the cockpit) when I am away from the boat
at night and on a foggy night even when I'm aboard.
When using it as an anchor light I send it up via the main halyard
on a sennet staff... in my case a 4 ft. varnished oak stick. This can be a royal pita on a blustery night but once up with the halyard
tensioned it is pretty stable.
In the cockpit
at night it makes my boat easy to pick out and easier to find in a fog
... it is also a cheery thing to find burning away when I have to get up to check anchor/mooring lines etc.
Then again I've met those who find the idea of a lit anchor light aloft understandibly a bit unnerving (the same sensible folks who don't approve of Molly Bs wood-fired stove) Fire on boats... hmmm