That's what he made his money with. Hauling heavy loads around that part of Alaska and making parts in his machine shop.
You would be surprised at what those boats sold for in the 50 and 60s. Sort of like $200 jeeps.
Even for scrap, you have labor, and have to have a market.
One of the minor points that gets brief mention in the show, is that there is a coal deposit on the ranch, and they can just go down to the beach and pick up coal.
I also roll my eyes when the voice over goes on about how important killing a deer, moose, bear, sheep is to their winter food supply - as if someone who owns a couple of hundred cows needs a deer for their protein supply.
Same with Glenn Villeneuve on Life Below Zero. Goes on and on about killing a sheep for winter meat. Sheep hunting for survival is stupid, because it is a negative sum activity. The goal of survival existence is to expend calories in the most efficient way possible. You don't see any of the aboriginal peoples sheep hunting.