The Bone Ships - RJ Barker (Book1 Tide Child Trilogy)

For generations, the Hundred Isles have built their ships from the bones of ancient dragons to fight an endless war.

The dragons disappeared, but the battles for supremacy persisted. Now the first dragon in centuries has been spotted in far-off waters, and both sides see a chance to shift the balance of power in their favour. Because whoever catches it will win not only glory, but the war.