 Soon, however, it was shown that the galvanic action set up between the copper on the "yellow metal" sheathing, and the iron frames tended to rapidly deteriorate the ironwork, and perhaps, sooner or later, hasten the loss of the vessel.So rapid, indeed, was this wasting of the frame found to be, that for some time past the composite system has been, so far as regards merchantmen, quite abandoned.Some ships, however, are still built "composite" for the Royal Navy, especially such craft as are intended for use on foreign stations, and whose duties would render frequent docking impossible.