Sea Hunter
By Paul Garrison 

In his catamaran, Oona, David Hope offers charters to scuba-diving tourists. At the beginning of this story, he is rushing back to Tortola in the Leewards when he has a confrontation with a nuclear sub, then spots a dolphin as large as a killer whale.

Arriving back in Tortola, Hope is disappointed to discover that his charter, which was to provide the money for long-overdue boat repairs, has been canceled. Sally Moffitt, an underwater filmmaker, wants to film the breeding habits of short-snouted spinner dolphins and charters his boat. They just get out to sea when they encounter the giant dolphin that David had seen earlier. After the sighting, they are invited aboard a huge sailing vessel owned by a wealthy naturalist, Bill Tree, who is doing research on dolphins. While they're aboard, Tree has their catamaran bugged so he can eavesdrop on Hope and Moffitt.

Intrigued by the giant sea mammal, Hope and Moffitt follow it north, trailed by Tree in his sailing vessel. The dolphin is actually a genetically-engineered mammal, a cross between a killer whale and a dolphin, dubbed a "killphin" by the Tree scientists, and programmed for a mission of doom: to destroy nuclear subs which are holding a rendezvous in the North Atlantic.

Paul Garrison is a one of the foremost authors of high sea adventures. Think Bernard Cornwell with shades of Clive Cussler, featuring desperate villains, electrifying chase scenes, and technology pushed to the edge. I have become a serious Garrison fan, and am eager to read his earlier books Buried at Sea and Red Sky at Morning.