At last we seem to have found a thread for people without the 'Definitive Book of Folk Songs'. I thought I was the only one without a copy!Radriano. Quite right. Songs did flow between land and sea. The shantyman that was afraid of stealing a verse or the whole song if it was worth stealing was no shantyman. But as you say there were work songs (shanties) and entertainment songs (forebitters). I doubt that sailors were anywhere near as choosie as todays 'authorities' on what could or couldn't be sung. They just got on and did it, and bugger where it came from.
Who makes up these rules, anyway?
Brian