Here's the Crow's Nest, from which one would keep a look out for pods of whales and their tell-tale plumes. The crow's nest of popular imagination is practically a small room on top of a mast. Nice and enclosed. These guys, on the other hand, have a couple of planks and a metal hoop. And by contemporary standards, that hoop/railing would have been an almost ostentatious display of workplace safety.
This piece is the only one in the series that is more based on photo-reference than drawing-on-location. What can I say. I wasn't prepared to shimmy up a mast with a sketchbook clamped in my teeth for the authentic point of view.