The 'Mike' from New Zealand mentioned above would likely be Mike Stanley, no longer of NZ now in Oz I believe.
This is his version. A few variations, the most obvious, a two line chorus, not three with one missing as someone asked about.

THE MAURETANIA

Now in nineteen hundred and twenty-four
I found meself in Liverpool on the floor
So I went to the Cunard office door
And got a job on the Mauretania

    She surely was a slaver,
    Ah to hell with the Mauretania

Well the Mauretania's a wonderful sight
She's sixty-four fires they're all burning bright
And they work you hard from morning till night
Tryin' to fire the Mauretania

Now the Mauretania's coal was full of slate
And that's what buggered the four to eight
Yes that's what buggered the four to eight
Tryin' to fire the Mauretania

Now the eight to twelve were much better men
But they were knackered by half-past ten
Yes they were knackered by half-past ten
Tryin' to fire the Mauretania

Now the fan's on the bum and the fires won't draw
And that's what's beaten the twelve till four
Yes that's what's beaten the twelve till four
All aboard the Mauretania


So come all of you firemen, listen to me
A Cunard greyhound spells purgatory
So stick to the coast and don't go deep-sea
Tryin' to fire the Mauretania

Jack