The Power and the Miner are deep sea the other 2 are yes "lakers" the first 2 were "self Unloaders" and could unload anywhere with out a "shore gang".. we hauled gypsum, coal, iron ore etc in those.. They had 3 sets of conveyors in the hold with gates all along them that dropped the product onto the conveyors that fed ionto that boom on the deck ..it could be positioned over the pier and pile the product into big piles..also salt from the Windsor Ontario salt mines (thus Windsor Salt brand salt)