This is a song written by an unknown sailor, sung to Down Below.
CORROSION HAS SET IN
Tune: Down below.

Corrosion has set in
Dahn below.
The plates are getting thin
Dahn below.
There's a leak in the fore peak,
And how those bulkheads creak,
I hope we'll last the week
Dahn below.

Boiler room's a-leaking
Dahn below.
Crack is nicely seeping
Dahn below
Fire and bilge will do their best
While the diver's getting dressed
Splinter-box will do the rest
Dahn below

Chippy wears a frahn
Dahn below.
It's coming in again
Dahn below,
They've taken up a shore
To the for'ard naval store
And they're sawing up some more
Dahn below

. Chippy's got an ulcer
Dahn below.
It plays him up a treat
Dahn below.
His feet are getting wet
As he watches concrete set,
But he's short of 'aggreget'
Dahn below,

The ship is like a sieve
Dahn below.
I hope they're PST
Dahn below.
For the lifeboats they inflate
Premature. Can this be fate?
Oh we're in a ghastly state
Dahn below.

Beleived to have been about HMS Chilcompton.
there is one, maybe two verses missing.
Anyone know them?