Tentacles by Roland Smith
Since Marty and Grace found out that they were cousins, not brother and sister they have lived with the elusive, Travis Wolfe. Wolfe always on the hunt of Cryptids, is making his way to the South Pacific to capture a giant squid, ALIVE!
But wait, it appears that their huge freighter may indeed be haunted, with someone on board trying to sabotage their every move. The dinosaur eggs have hatched and someone must guard the hatchlings from imminent danger. Grace and Marty set out to follow the clues, get the answers or will they be in mortal danger?
Kudos to Roland Smith for writing a sequel every bit as good as the first book, Cryptid Hunters.