Hard questions!
Looks like one navy sailor and a petty officer, but I doubt the shipping line had black captains!!
Stanley is not standing straight up, looks like he’s leaning slightly forward and I can’t figure what his right hand is doing, And it doesn’t look like they are on a shipping pier either!!!
The Black Star Line had 14 cargo ships out of Ghana, several took passengers, and ALL of their crew would have been GHANAIAN! Nkrumah established The Black Star Line shortly after the independance of Ghana.