There are several versions of this song on YouTube, with slightly differing tunes and approaches to singing, and a few sets of lyrics on Mainly Norfolk.

The song raises some interesting questions.

Regarding the lyrics generally: how many folk songs have first person narrators who admit to being able to write? How many of the crew in the 18th century or before would have been literate, even allowing for abuses of impressment? Not to mention the access to writing materials and somewhere to write and membership of a group that had 'rooms and cabins'. He isn't mentioning guns or cargo or rigging etc. or the dangers of being on deck. Though since the crew appear only to have known a storm was coming when the captain saw the sign in the sky they don't seem to have been particularly experienced.

I don't agree that he is addressing himself; he is addressing Nancy.

The version mentioning Zeus seems to me likely to have come from the pen of somebody with at least some passing familiarity with classical mythology.

I would not be at all unhappy with the idea that the words of the garland had been written by a landsman who never went to sea. Some of the lexis such as 'discern' feels relatively educated.

The key and striking thought in the song seems to be the idea that you cannot run away from a sinking warship whereas soldiers have some chance of escape.

It fascinates me that people like Steve can provide so much documentary evidence about the past of a song. And then we novices can find sung examples on line to listen to.