Short review: Sea-going Marty Stu copies the Harry Potter format into a fantasy setting that might be called imaginative by a gifted liar, but is mostly just unlikely.
Longer review follows.
Plot: Halcyon Blithe joins the Arcanian navy on a dragonship of the line and excels. Eventually also makes one bad blunder, is forgiven, beats a villain and rescues the ship. The end.
Our hero is the worst case of unlikely excellence in a character since certain 19th century heroes. His special talents and Marty Stu traits so far, let me show you them: red eyes (from demonic blood), being the seventh son of a seventh son (which makes his magic better), being a late bloomer (makes his magic better), a dragon-speaker (rare magical talent), a rope speaker (rare magical talent), knows the articles by heart, is a Blithe (almost all his family are naval officers), unusually tall and strong for a 16-year old, beat the marine champion in their very first bout, beat the blast-pike Navy champion first time he (Halcyon) ever handled the weapon (though using it the way he did, according to said champion, usually takes years of study), was the aimer of the only blast-tube (cannon) crew to hit the target in his first practice, should I go on?
The book wasn't even well-written. Not only does the formula greatly resemble the Harry Potter books (lessons in sea-going life acquiant the reader with the fantasy world, and then there is a puzzle and a dangerous situation), the phrasing is straight out of badfic. "His father was gone, but his spirit lived on in Halcyon." WE DON'T CARE. We don't know his father. His father was never in the book. Halcyon also talks to himself, aloud; the spy is absurdly easy to spot, and everybody tells really bad jokes. And I won't even go into how they sugarcoat extreme cruelty towards dragons.
Enough. Avoid this book, it's a waste of your time. I have read worse, but not that many.