It has excellent characters and the action never stops. I think the cover of this book does it a dis-service, in that it looks like one of those WW2 naval novels or a techno-thriller, when really this book is neither of those. Instead it relies on well drawn characters (who are not invincible) who use their intelligence and common sense to get out of a tight situation.
An above average thriller, even for those who aren't ship buffs. (I'm not and it held my interest)