The Cement Boat by Stu Reininger.
“…The strangest thing about the Larinda may not be that she’s made of cement. Belowdecks, in the boat’s main salon, you’ll find a rare, 100-horsepower (1,400 foot pounds of torque) Wolverine diesel that was built in 1928. Mahan was obsessed with Wolverine motors (he eventually bought rights to the defunct company), and searched Panamanian jungles fruitlessly for an 1895 Wolverine locomotive engine that had long been abandoned at the end of the tracks. When he finally found the 1928 power plant in a marine salvage yard, he had it restored, trimmed in brass and painted bright green. After his massive search, Mahan couldn’t bear the thought of hiding his bounty in the engine room, so now it sits in the salon, gleaming, and reminding you that this boat is extraordinary in many different ways…”