I inherited an ocean going fishing power boat. I know they are kind of presumptuous, but are classic boast shoes actually useful? Are they comfortable? Do you wear them without socks. Can you wear them on a small shitty boat, or do you have to have an 80 foot yacht? What is that cord going around them for? Will I look like a dick wearing them around town?
You can wear them on a boat. You can wear them with a goat. You can wear them near a moat. You can wear them in Terre Haute.
Yes, they are, in fact, built to be worn on boats – the rubber sole is meant to keep them from leaving marks on the boat, they are supposed to be good for being grippy on a wet surface, and the leather is waterproofed. (And, yes, traditionally, they’re worn without socks.)
I’m not sure if you’ll “look like a dick,” but you may look like you’re a refugee from 1987. 
Boat shoes are fine, just about anywhere, get the ones that have soles designed for boats, ie kinda non slip. Yes, comfortable, and you can wear them without socks.
I wore neoprene short boots or higher rubber boots when fishing however.
It’s the captains hat that can make you look like a douche. Get a hat with a long bill instead.
They typically have small sipes on the bottom for wet traction and are white so they don’t mark your expensive teak decking. Required fashion around town for the yacht set but they wear out very quickly. No socks or Buffy will laugh at you.
I went to a boat show where a guy I know had a boat on display. He wouldn’t let me on board without boat shoes. He wouldn’t let us on board in socks because, as he put it, “Don’t be silly”.
I grew up around boats, and they were standard wear. Very comfortable, too.
Yep, non-skid treads and white soles so you don’t mark the deck. But, I always wore socks with mine. And so did everyone I raced with. Maybe it’s the difference between small boat sailors (socks) and large powerboat drivers (no socks). 
I was already given a doucebag captain’s hat. It’s dark though, so I’m going to get a white one so I look like Alan Hale.
I’m convinced! There’s a crappy one on Amazon for $25. I’m gonna do some keelhauling!
I’m thinking that boat shoes will be good to use as my outdoor slippers for when I have to go and grab the mail and don’t want to put on real shoes. I think I can treat them like slip-ons for short jaunts.
Uh, the skipper’s hat was dark.
Goddammit. Well, I’ve saved the price of a new skippers hat.
More or less back on topic, boat shoes are well suited for that use. I no longer wear the stereotypical Topsiders though. I wear a more sneaker-looking shoe but with the same white, siped sole.
That tread really does seem to stick to wet boat surfaces well, even though the boats I said are all fiberglass, not teak.
My boat’s all fiberglass.
I grew up around boats and topsiders we’re definitely a preppy affectation. Deck shoes like in your second link were more practical. Cotton uppers and laces stood up to seawater far better than leather. I still don’t know what the point of the encircling leather thong was.