Building an aircraft carrier hull is no small matter. Today the US Navy is designing its next generation aircraft carrier (on the drawing board as CVNX), and once again weight, and hull steel certification, is on everyone's mind. Ship hulls are in some of the most demanding environments imaginable for any material. They have to withstand changing temperatures – from the tropics to the Arctic. Pounding ocean water subjects a ship's hull to constantly changing load and torque, causing complex and often severe stress states. And, in a fighting ship, there is the potential for additional trouble.
A new high strength, low alloy steel – called HSLA-65 – is on the market and both the shipyard as well as the Navy believe that the new carriers can shed a few pounds if this steel is used in the carrier hulls. Preliminary calculations indicated that if it was used in hull plate, it could provide equal or greater service life than the traditional high-strength steel, but be thinner, and therefore weigh less. The same would be true for the hull's interior supporting structures. HSLA-65 is stronger and tougher than conventional steel, and has proven itself in commercial bridges, pipelines and other ship above-deck structures.