Melville addresses his readers
"ye lucky livers, to whom by some rare fatality your Cape Horns are placid as Lake Lemans, flatter not yourselves that good luck is judgment and discretion; for all the yolk in your eggs, you might have foundered and gone down, had the Spirit of the Cape said the word."
Would anyone want to explain or paraphrase "for all the yolk in your eggs"?
The yolk is, ostensibly, the ‘good bit’ of the egg, located in the ‘mediocre bit’ ie the white.
Here, the white is likened to the sailor, and the yolk is likened to ‘what he has inside him’ - ie the wit, courage, bravery etc - needed to navigate the challenging Cape Horn.
It means he’ll need to call on all his inner resources - his ‘yolk’ to succeed.
It’s a bit like saying ‘the money in your wallet, or ‘the lead in your pencil’.
The yolk of an egg can be viewed as its reproductive strength. A person who is not an experienced whaler has a "supposed" strength (his yolk) which has never been challenged by a Cape Horn gale. Thus a non-whalers idea of strength is not sufficient to assure against the difficulties presented by navigating Cape Horn.
Cape Horns are death trap; Lake Lemans placid tourist hub. By some mis-chance, both of them appear to you tranquil but that must not lead you to confuse good luck with judgement and discretion. " For all the yolk in your eggs ", inspite of all your discretion and finer judgement you may not be able to read that seeming is not like the seeming. you might as well just fumble and falter with your wealth of judgement. It's a chance occurance. To achieve something by judgement is one thing that should never be confused with all accidentals happening got by sheer luck.
yokenotyolk? I bet you were just waiting for someone to call out your eggcorn :)