The variety of alloys utilized is spectacular: weathering steel for patina, marine-grade light weight aluminum for weight cost savings
https://www.mediafire.com/file/r8uuz415kpats7h/pdf-72890-82269.pdf/file
The series of alloys utilized is stunning: weathering steel for patina, marine-grade light weight aluminum for weight savings, and duplex stainless for rust resistance in rough environments.