Excellent story telling with this book. You could almost see this as a group of scenes on being on a WWII German U-Boat. It's not just battle after battle, really conveys the details on what a u-boat was and how it's kept up. Lots of crew scenes too not just the officers.
One tiny bit was the difficulty of maintaining your focus on a 8 hour shift being a lookout on the bridge. Even down to how heavy the binoculars felt after a couple of hours. Well with my time reading and was hard to put down.