Honestly pretty simple if it is possible allow players to make maps, this would probably be a good feature to add to elite or premium subscriptions. Basically they can drag and drop tiles and any order they want and put ports where they want or allow it to stay random by placing blank tiles that get filled in. Add Fog where they want, you could allow them to place the number tiles too or keep this blank to keep it random. Sorry if this is confusing tldr: Players can make and customize maps.