Sheet steel piling corrodes most severely around the waterline and to a depth of about 15 inches below it. To restore the piling to its original strength, a reinforced-concrete repair panel must extend from above high-water mark to about 6 feet below normal water level. The work can be completed most efficiently in panel widths of 10 feet. The first step is to construct a three sided working chamber that can be floated in to position so that its open side is sealed against the piling. After the working chamber has been pumped dry, the piling must be very carefully cleaned free of all marine growth and rust scale. A through cleaning usually reveals the presence of "spontaneous" corrosion holes in the piling. Such holes should be sealed by welding a steel plate over them. When the piling is clean and sound, struts to support the panel reinforcing mesh should be welded in place. The mesh is then welded to the struts. A monolithic reinforcement is finally surrounded by a prefabricated form which is lowered into position. Placing of the protective concrete can then proceed. An alkali-resistant cement should be used. As soon as the mix has hardened, the form is stripped and the working chamber is flooded with water prior to its use on the next section of piling. The portion of panel above water should be draped with wet hessian.