John-

I think you're on firm ground with "Blow Boys Blow" (aka Congo River and related to at least three other named shanties in DEEP THE WATER SHALLOW THE SHORE); it's also a work song that the stevedores used on the docks in Australia as they pressed bales of wool.

And here are some more notes on shanties derived from minstrel or plantation field songs:

Coal Black Rose

Round the Corner Sally (Round the Corn Sally)

Doodle Let Me Go

Miss Lucy Long

Gimme de Banjo

Hilo, Boys, Hilo

And I can't resist a note on "Hilo" which in some shanties is taken as a reference to a favorite port in Western South America but was in fact transcribed by one curious observor much earlier in this plantation field song:

Oh, this is the day to roll and go,
Hill-up, boys, hilo;
Oh, this is the day to roll and go,
Hill-up, boys, hilo!

It's also of interest that such "nautical" phrases as "roll and go" and "rock and roll" first appeared in the plantation field songs.

Cheerily,
Charley Noble