Having read all six books of the series, I will post this "series review" on all six book sites rather than do a review of each book.
Gobbell nicely mixes fictional characters in among actual events and real historical figures of WWII. It's an enjoyable read, although the author's character development is somewhat shallow and forced... shades of comic book defiance and heroics that just rings hollow if you are conversant with the history and with the actual first hand accounts of veterans who were there and experienced much of what LT Ingram did. Nevertheless, if you have an interest in WWII, the author does an excellent job of mixing in authentic technical and historical data with the flow of action involving his fictional characters - destroyers, aircraft, bombs, naval culture and procedures... all well done and credible. The personal relationships and dialogs are soap opera-worthy and artificial in the settings in which he presents them. Lots of sarcastic retorts and impulsive bravado fitting for a teenaged superhero but not a supposedly mature and experienced commanding officer. I found myself just skimming over those interludes to get past them quickly.
And the author could have used a continuity editor. For example, and not to spoil the series, but in one book Ingram is held captive on a Japanese sub with a Nazi interlocutor, supposedly headed for France... eventually the German rejoins the Kriegsmarine at sea to continue on to Europe. (I'm glossing over a lot of details and action in order not to spoil things for potential readers). He is offered the opportunity to ride U437 to Kiel in a couple weeks - he declines for a much riskier way sooner. Two sentences later the character he is talking to remarks he should have boarded U689 because it would have been safer....
In another example, his Intelligence officer friend Toliver briefly mentions the Redman brothers in reference to their internecine warfare between Op-20-G in Washington and the Rochefort shop in Honolulu (all of which is true). Ingram asks who are they and Toliver puts him off - no time to explain now. They have no further interaction at all, yet on the next page, with Toliver having left, Ingram mentions he knows all about the Redman Brothers.... again, maybe just me but naggingly irritating.
Maybe it is just picky me, but that sort of inconsistency in narrative annoys me... and it is fairly prevalent. However, throughout the combat sequences are excellent, as are the times and events at sea. The fictional story lines centered on Ingram overlaid on the actual events and historical figures of the War are compelling and give the reader a good sense of life in those times. The series is good WWII historical fiction.... better in books 1-4 than 5 & 6... and book 6 is set 30+ years after the war with then Admiral Ingram a relatively minor character to the story line involving his son Lt Ingram. Weakest one of the series.