Navvy is still probably the most common word in England for people doing labouring work, mostly on building sites, and there's no implication about nationality or colour.

"Working like a navvy" or "working like a nigger" would at one time have been used interchangeably, meaning working bloody hard. Eiuther way it carries a certain mark of respect. These days you wouldn't get the klatter, maybe because the only people who'd say it wouldn't have that respect.

As for "Hogeye" in shanties, I've always understood it meant "arsehole". I've got a feeling that's what Stan Hugill said it meant.