A rather dirty traditional sea shanty, along the lines of Fairport Convention's Bonny Black Hare. I think it may have been performed by northern UK folk band The Spinners, but I only have a rather dodgy recording on cassette with no inlay card.
The fireship in question is a young woman prostitute, who turns out to be more than the young sailor who partakes of her wares anticipates. There's lots of very suggestive nautical imagery and it's all rather fun, although not one to sing to your grandmother.
As I strolled out one evening upon a night's career,
I spied a lofty vessel, and after her I steered.
I hoisted up my sig-i-nals which she very quickly knew,
And when she seen my bunting rise, she immediately hove to.
She'd a dark and a roving eye,
And her hair hung down in ring-a-lets.
She was a fine girl, a decent girl,
But one of the rakish kind.
Oh sailor, please forgive me for being out so late,
But if my parents knew of it, but, sad would be my fate.
My father is a minister, a good and honest man.
But my mother is a dancer; so I do the best I can.
I eyed that girl both up and down for I'd heard such talk before,
And when she moored herself to me, I knew she was a whore.
But still she was a pretty girl; she shyly hung her head.
"I'll go along with you, my lad,'' this to me she said.
I took her to a tavern; and treated her to wine,
But little did I think she was one of the rakish kind.
I dandled her, I handled her and found to my surprise,
She was nothing but a fire ship rigged up in a disguise.
So up the stairs and into bed I took that maiden fair.
I fired off my cannon into her thatch of hair.
I fired off a broadside until my shot was spent,
Then rammed that fire ship's waterline until my ram was bent.
Then in the morning she was gone; my money was gone too.
My clothes she'd hocked; my watch she stole; my sea bag was gone too.
But she'd left behind a souvenir, I'd have you all to know,
And in nine days, to my surprise, there was fire down below!