It is for compliance with ABYC standards, which are not law. It may be required for commercial use of the vessel.

In addition, the ABYC standard for heat shields is part 183 subpart J Fuel Systems - which applies only to gasoline engines. The industry has conflated this with all fuel systems, and the heat shield has found its way into diesel installations, even though not explicitly specified in the standards.

It is pretty egregious that they charge $50 for a stamped piece of metal.

Mark