Armed with a wood chisel and a hammer, Sherman spent four hours carving a hole in the bottom of the plywood-and-fiberglass hull, which was now the submerged boat's top deck and visible to any passing vessels.

CNN: Shipwreck survivor recounts drama on high seas

Armed with a wood chisel and a hammer, Sherman spent four hours carving a hole in the bottom of the plywood-and-fiberglass hull, whch was now the submerged boat's top deck and visible to any passing vessels.

CNN: Shipwreck survivor recounts drama on high seas