It's called Rapier.

It is the most remarkable advance in naval technology in decades - an attack submarine capable of incredible underwater speeds. There is only one problem: A key element of the prototype has suddenly vanished, and the man who developed it is dead. Now it's up to NUMA director Dirk Pitt and his team to go on a desperate international chase to retrieve it. But as they close in on the prize they discover that they're facing a much, much greater threat than they ever imagined possible. It's clear that if they fail in their mission, the world as they know it might end up a very different place - and not a very pleasant one