Tentacles (English, Paperback, Roland Smith)

Marty and Grace O’Hara’s globe-trotting parents disappeared while on assignment for a nature magazine, and now they’re living with their Uncle Wolfe, a scientist fascinated by cryptids – creatures that appear in myths but haven’t been proven to exist, such as the Loch Ness Monster.

Wolfe is planning an expedition to New Zealand to track a giant squid, and he’s rented a huge (and possibly haunted) freighter for the trip. But someone on board is determined to sabotage their mission–and if Marty and Grace keeping poking their noses into things, they might end up the saboteur’s next victims!
Source- Goodreads.com
E24