In this poem old Bill Adams seems to be letting loose a broadside at the armchair nautical poets:

By Bill Adams
From WIND IN THE TOPSAILS, edited by Bill Adams, published by George G. Harrap & Co., London, UK, © 1931, pp. 163-164.

TO THE LUBBER POETS

Scented soap and lily hands
A long farewell to you!
I'm away to foreign lands
With a hard-case crew.

Luck to you, my gemmy writers,
I've got Dago Joe,
And a crew of squarehead blighters
Roaring in the snow.

Do ye hear them, lily fingers?
Do ye catch their tune?
Do ye hear them fo'c'sle singers
Shouting to the moon?

"Squall to windward!" Bosun yelling,
"Up there! Up you go!"
Feel the southern ocean swelling
To the coming blow!

Oh, the sea is black and crying,
And the wind cries too,
And a swinging clipper's flying
For a singing crew.

Poetry to me is motion,
And the rolling thunder,
And the crashing black commotion
When the rail goes under.

Ho, I ain't no gemmy writer!
I'm a hard-case, see?
I'm a poor barefooted blighter,
But, thank God, I'm me!

I'm not sure how the slang term "gemmy" is being used here. It may be a sarcastic adjective, akin to calling someone "precious."

Cheerily,
Charley Noble