Sloppy, clumsy, incompetent writing.
The characters have no depth, their actions are illogical, their feelings have to be explained in plain words because there is no skill to suggest
anything, and even the word choice is frequently very unfortunate.
Nor is the plot anything special to make up for the prose quality. The hero gets pushed around - there are some failures - the mission only progresses because he takes it on himself to disobey orders and choose a better course of action - then finally the heroic hero heroically takes over the whole enterprise, which is instantly crowned with success.
Really, this thing about disobeying orders is in such demand with the adventure writers, one wonders that there was any discipline in the Navy at all. But then, obviously the adventure writers are lying embroidering.
I love naval fiction in general, but that's the only reason for my getting through this to the end.