I found an alarming installation on my '78 Tolly 48 when I inspected my main engine thru-hulls. My OEM thru-hulls are bronze gate valves. While I would consider flanged ball-type seacocks superior, I chose not to upgrade, given mine are still sound and function easily and correctly. HOWEVER, both my thru-hulls were equipped with PVC elbow barb fittings, albeit with the intake hoses properly double clamped. In addition, both of the raw water pumps were also equipped with PVC barb fittings. I'm not sure if these fittings were OEM, or changed sometime in the past by a previous owner. But the PVC fittings on my thru-hulls and raw water pump intakes definitely violate current ABYC recommendations, and I immediately replaced mine with bronze hardware. Incidentally, all this was missed during a recent pre-purchase mechanical and separate condition survey by highly regarded professionals. Food for thought.