My friend Jim Saville posted this explanatory comment on another forum which some may find helpful, or not:

"Than you for bringing this poem to light. I have been a fan of OS as he was known to Punch afficionadoes for many years but this marvellous example has evaded me until now.
There are hints of Carroll as well as Kipling in the lines and one can even hear Spike Milligan somewhere (although in fact he probably copied OS 40 years later on).
I am captivated by the way he has managed to continue the tale and the puns through so many twists.
A really excellent piece of non-sense.
BTW
Most people will be able to pick up the nautical references and puns but one may escape. The P.M.G. refers to the Pall Mall Gazette, an important paper for the high society and military of that era."

Cheerily,
Charley Noble