Thanks, everyone, for all the comments so far. They've been very helpful. Here are a couple of redesigned covers, taking into account some of the things that have been said. I don't want people to automatically think "Western" when they look at the book. I've also made them smaller so they'll look more like they will on Amazon's site. Of course, the good thing about all this is that we can try a cover for a month or so and then swap it for another one if we want to.
'To a destroyer every submarine was an enemy'
2 hours ago