Killdozer! has a lot of his own experiences on the merchant marine and construction jobs in the pacific, if I recall. He goes into lots of details about the machines.
So sturgeon and Jack Vance(my favourite) were both in the merchant marine. Jack vance actually wrote a lot of the “Dying Earth” on ship.
Freegards
I don’t think I have an all out favorite. Always liked Niven. Pournelle.