Hmf... On the surface, the suggestion looks good. However, when deliberating on it, I decide that there are far too many blank spots on the map, and it would be much better to explore the ocean than to assume that it's the same everywhere. Exactly identical ocean tiles are boring. On the old maps of the times when Magellan and Vasco da Gama were sailing around the continents, in the Age of Discovery, many a sea serpent and beast were mapped. Currently, when wildlife is known much better - flying fishes, turtles, dolphins, whales, seals, sea snakes, eels, penguins and many others - they are not added to the maps, except, occasionally, tourist maps. Hence, boring ocean tiles.
Best wishes.
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Per aspera ad astra...