Peace? Peace??!!?!!! What on earth do you want THAT for?
Mornin’ David. 
Peace indeed.
Ben
In an attempt to help I suspect I may just muddy the waters but here goes .
My OED (Concise, 9th Ed, 1995) has
chanty var. of SHANTY
and
shanty n. (also chanty)(pl. -ies) [probably French chantez]
In any case, David, we can’t have peace for long. Well, not where I am at any rate, since I have to go and practice my flute, as I have my grade 3 next Friday (peace = absence of noise). (Aagh! Less than a week - wish me luck. )
Or were you giving me an instruction to shut up (another of the meanings of “peace” given in the OED)?
Interestingly, my reprint of Admiral W. H. Smyth’s nautical dictionary The Sailor’s Word-Book (pub 1867) has neither. Shanty’s there, but the sole definition given is “a small hut on a beach”, which has nothing to do with this discussion.
Smyth was born in 1788 and went to sea shortly after the turn of the 19th century. He retired a full admiral in 1825, and died forty years later just as his 750 page magnum opus was going to press.
Sea shanties historically were more common in merchant vessels than in the royal navy*, but Smyth includes all manner of non-naval material.
- Partly because of the presence of a detachment of marines in all but the smallest naval vessels. The marines usually had at least a fife and drum, which were often used to supply music in place of shanties.
Ah, but now that I have been provoked into loading this CDrom OED that I bought in a charity shop I can quickly tell you that it is:
“C19: perhaps from Canadian French chantier ‘lumberjack’s cabin, logging camp’.”
and so maybe another example of the ‘ch’ being spelled ‘sh’ to keep it soft in english.
Ben - the ‘peace’ was echoing MTGuru in acknowledgement of his moderating influence; I suppose he may have meant it as ‘shut up’ in a schoolteacherish sort of way. Good luck with the exam.