I do my rhumb lines basically as a a set of compass lines (turned into a brush) and place the center at the ports. So If you sail directly east then you follow this line or if you sail southwest then you follow this line. The colors are nice and I think you did a good job with what you had. The pattern on the land might be a little big because it looks like there are some big canyons with that pattern. I think a little more work or development and you might get something pretty cool. By the way, who did the artwork on that Rhim website? It's awesome.