MIL-HDBK-843, MILITARY HANDBOOK: SHIP METALLIC MATERIAL COMPARISON (20 AUG 1993)., This handbook provides Naval Sea Systems Command (NAVSEA) guidance for the selection or substitution of the most common material types and forms used in ship design, construction, overhaul, or repair. Recommended specifications have been established and cross-indexed to prior specifications. By using the consolidated material specifications provided by this handbook, the volume of redundant specifications, stock numbers, and associated material inventories can be reduced.