The Motor Rangers on Blue Water; or, The Secret of the Derelict by John Henry Goldfrap is an adventure novel that continues the thrilling escapades of the Motor Rangers, a group of intrepid young adventurers known for their exciting and daring exploits.In this installment, the Motor Rangers embark on a maritime adventure as they navigate the waters of "Blue Water" in pursuit of a mysterious derelict ship. The story combines elements of nautical adventure with mystery, focusing on the secret surrounding the abandoned vessel.