Two of the shanties mentioned in this thread (i.e. Hog Eye Man and Johnny Come Down to Hilo) have long been favorites of mine.
I first heard Hog Eye sung by Ian Campbell, I believe, on a Topic 12-inch LP. From the very start, I was aware that there were traditional "filthy" verses to it. I've met people who have claimed to know some but no one has ever sounded really convining to me. (Most of the stories usually involve a bottle of rum and Stan Hugill, by the way.)
I first heard Johnny Come Down to Hilo, again, on a recording and it remains one of the very best renditions I've heard to date. Bill Bonyon put together a very fine LP of maritime song about 1960 and it's featured on that Heirloom record. I never met Bill but he was a friend of Frank Warner and a neighbor of my friend, John Baker, in Bayport, NY.
Bob Conroy, my singing partner, sings Johnny Come Down to Hilo and I'll ask him to visit this thread and put down his words.
All the best,
Dan Milner