What is the main conflict in Cyclops by Clive Cussler?

The book, Cyclops, by Clive Cussler, is a techno-thriller featuring well-loved protagonist, Dirk Pitt. The story opens with the puzzling events aboard the Cyclops, a Navy collier, in 1918 with a captain who drinks more than he works and a strange cargo with equally strange passengers that board in Rio de Janeiro. The Cyclops has been issued a no communications order by the Captain and refuses to answer a distress call from Crogan Castle fifty miles away, near the northern coast of Cuba. Shortly after, the Cyclops encounters a similar rogue wave that the Crogan Castle had mentioned; only the Cyclops did not survive. Her secrets lie deep under the water with her.