Set aboard the submarine Leviathan D. S. V. (Deep Submergence Vehicle), this novel focuses on the early years of the International Multiple Threat Alert Command and its defense arm, the United Earth Defense Command. In the early 21st century, the United States was attacked by forces from Al-Qaeda. The United Earth Defense Command commissions the construction of the submarine Leviathan D. S. V. to keep the peace and explore the vast oceans on Earth.

Hello,

it seems a little like star trek underwater or a clever update of 20000 leagues under the sea,
it could be interesting,

if you want to transform your description?into a logline I suggest you to read the tutorial then try to focus only about the main character and his main goal - forget the backstory, just tell when the real story starts.

This is a logline for a novel from my understanding and as such it should describe the story in a way that best fits a book, however, there are several fundamental similarities with stories for film that the logline still needs to comply with.

The logline is too long at 74 words and makes several leaps of logic the reader can't follow with out detailed explanations such as: mention of un known organizations "...International Multiple Threat Alert Command..." and "...United Earth Defense Command..." and how a submarine will keep the peace as there are already many sophisticated submarines paroling the worlds oceans.

Lastly and most importantly a main character and goal are missing from the concept, who wants what and why?

If you want to rewrite this logline I suggest reading this first:
https://staging.loglineit.com/howto/

?Hope this helps.

This is a logline for a novel from my understanding and as such it should describe the story in a way that best fits a book, however, there are several fundamental similarities with stories for film that the logline still needs to comply with.

The logline is too long at 74 words and makes several leaps of logic the reader can't follow with out detailed explanations such as: mention of un known organizations "...International Multiple Threat Alert Command..." and "...United Earth Defense Command..." and how a submarine will keep the peace as there are already many sophisticated submarines paroling the worlds oceans.

Lastly and most importantly a main character and goal are missing from the concept, who wants what and why?

If you want to rewrite this logline I suggest reading this first:
https://loglines.org/howto/

?Hope this helps.