Albany was the last US submarine built via the traditional "keel up" ship construction method.[citation needed] Thus, it was the last submarine to "launch" down the shipway. The Albany and USS Topeka, differ from other members of the Los Angeles class as their pressure hulls were partially manufactured using stronger HY-100 steel rather than the HY-80 steel used in the manufacturing of all other Los Angeles class submarines. This was done to test construction methods using this steel, which would later be employed in the assembly of the new Seawolf-class submarines.