For the further past though, it's not too surprising that black Americans wouldn't know about sailing traditions.

This reminded me of a conversation I had with some local folk musicians I met while living in South Carolina around 15 years ago. I had been singing some Oz songs and some shanties and they commented that they didn't know of any shanties 'from the South'. Without missing a beat I launched into Roll Alabama Roll. I might be wrong about its specific provenance (being from Oz and all, but they didn't correct me) and I didn't get into others that deal more directly with the cotton trade from the South but I was surprised this one wasn't right near the tops of their heads.

Perhaps the things that are intimately familiar to us (but not very problematic), when growing up, are not 'top of the pops' in our thinking much later on. This would be epecially true if those things were ones we were trying to change into something else that was 'better'.

Cheers, Rowan