Edward Stratemeyer 
Rover Boys Under Canvas 
Or, The Mystery of the Wrecked Submarine

A popular entry in the second-generation Rover Boys series, The Rover Boys Under Canvas follows the sons of the original Rover Boys as they participate in a classic ritual at Colby Hall, the military academy they attend: the annual school camping trip. Along the way, the boys uncover an intriguing mystery. Will they be able to crack the case without incurring the wrath of their commanders? Dive into this eminently entertaining page-turner to find out.