the official march of the Royal Navy of the United Kingdom. It is also the official march of several Commonwealth navies including the Royal Canadian Navy and the Royal New Zealand Navy. Royal Canadian Sea Cadets march to "Heart of Oak" during their parades. (It was also the official march of the Royal Australian Navy, but has now been replaced by the new march, "Royal Australian Navy.")
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[Richard holding sweater, preparing for Hyacinth's "light nautical buffet"]
Hyacinth: Oh Richard, that's not very Hearts of Oak, is it?
Richard: It's as far as I go, old seadog-wise. I'm not exactly tackling the armada.
Hyacinth: We are a seafaring nation, I will not permit you to walk in the shadow of Nelson and Raleigh with a sweater like that!
BBC. Keeping Up Appearances: What to Wear when Yachting (1992)
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the Captain made a little bow, ‘to break up hearts of oak, whether they’re in brigs or buzzums. Here we have ‘em both ways, which is bringing it up with a round turn, and so I ain’t a bit afeard as yet.’