The range of alloys used is spectacular: weathering steel for aging, marine-grade light weight aluminum for weight cost savings

https://www.4shared.com/office/xS_Ueh4fku/pdf-32330-62881.html

The series of alloys used is sensational: weathering steel for patina, marine-grade light weight aluminum for weight financial savings, and duplex stainless for deterioration resistance in harsh environments.