Hitting ships from long range with the 8" guns is difficult because of the precision required, but not impossible. It takes some practice and experience. The best way to score hits is not to "walk up the splashes", but to bracket the target.
Use sea mode, and guess the initial range of the target. Your ability to range targets and apply appropriate lead is something that just gets better with practice. If the first shot falls short, fire the next one significantly farther out. Hopefully it'll go long. Now you know your target is between those two ranges, and you can gradually close in.