Abstract: A system and method of reducing corrosion in the ballast tanks of a ship is comprised of a central inert gas manifold extending down into the furthest reaches of the ballast tank, a plurality of lateral gas distribution manifolds extending away from the central manifold, and a plurality of downwardly projecting diffusers connected to the lateral gas distributors that release the inert gas at multiple simultaneous points within the ballast tank space. A method is further presented for using the diffuser array to sparge the ballast water with the inert gas to inhibit microbiological induced corrosion.

Abstract: A (1) piping grid, nozzles and/or deflectors and/or diffusers placed on the piping at a certain intervals, and (2) header pipes connecting the piping grid to (3) an inert gas generator via (4) a compressor and (5) an optional cooler support efficient and effective injection of inert gases into all regions and volume of ships' steel ballast tanks, retarding or avoiding corrosion. Efficiency in use of generated inert gas, effective entrance of inert gas into ballast tank spaces that may be remote and/or difficult of access, and minimization of the elapsed time to fill the tank with inert gas while discharging essentially all oxygen-containing air previously within the tank, are all realized by progressive, staged, insertion of cooled inert gases from tank bottom to tank top, marshaling contained air and expelling it out the tank tops.