During the next eight years, Cox and his workforce of divers, engineers, and labourers engaged in the complex task of raising the sunken fleet. First the relatively small destroyers were winched to the surface using pontoons and floating docks to be sold for scrap to help finance the operation, then the bigger battleships and battlecruisers were lifted, by sealing the multiple holes in the wrecks, and welding to the hulls long steel tubes which protruded above the water, for use as airlocks. In this fashion the submerged hulls were made into air-tight chambers and raised with compressed air, still inverted, back to the surface.