The Rosabella is a work song dating to about the second half of the 19th century: different sources all pepper the time period but it is not possible to pin a specific date, it seems.

Nothing to do with the song, actually.

One Monday morning in the month of May,
One Monday morning in the month of May,
I thought I heard the old man say,
The Rosabella sails today.

Chorus:
We are goin’ on board the Rosabella,
We are goin’ on board the Rosabella,
We are goin’ on board, right down to board
The saucy Rosabella.

She’s a deepwater ship with a deepwater crew
She’s a deepwater ship with a deepwater crew
You can stick to the coast but we’re damned if we do
On board the Rosabella.

All around Cape Horn in the Month of May ,
All around Cape Horn in the Month of May,
Around Cape Horn is a bloody long way
Aboard the Rosabella.

Them pretty girls do make me grieve
Them pretty girls do make me grieve
They spend my money and they make me leave
Aboard the Rosabella.

One Monday morning in the month of May
One Monday morning in the month of May
I thought I heard the old man say,
The Rosabella sails today.