Getting To Where The Gouges Reside
The crew of the Great Lakes ore carrier Kaye E. Barker had enough. They had just finished up another season of dealing with leaks from the heavy-duty lufting cylinder that powered the ship's offloading boom. So far, they were only able to bandage the problem. Each passing year meant another set of replacement seals. Yet several months into the new season, hydraulic oil drips dotted the deck beneath the cylinder. Management at Interlake Steamship Company, the owner of Kaye E. Barker, wanted the next fix to be the last one for some time. "You add up the problems we had with this cylinder," notes Mark Barker, Fleet Engineer with Interlake, "and you get an on-going repair nuisance." "Top it off, the leading hydraulic oil is a safety and environmental hazard." The job of this massive one-foot diameter cylinder is to elevate the 250-ft.
(76.2 m) boom so that the vessel may self-discharge its cargo to shore. Stresses created by the load and the unforgiving environment took its toll on the ram. Gradually the chrome was flaking away from the surface of the ram — the visible flaking and deterioration evidencing the chrome breakdown. Within time, gouges as deep as .5-in. formed along the surface, chewing up every set of seals applied to the ram and leading to the annoying leaking problem.
"In addition to the other hassles," points out Barker, "the progressive leaking made our ability to hold pressure in the cylinder difficult." "During off-loading w e had to carefully watch the cylinder to make sure that it did not extend causing the unloading boom to drop and inch or two." Like all ships during winter lay-up, plans were made for a variety of maintenance projects as Kaye E. Barker pulled into its dock in Duluth. In anticipation of the cylinder problem, Interlake got together with Metal Surgery, a worldwide repair specialist to discuss strategy for re-plating the cylinder.
"We went into this project thinking we would need to pull the cylinder off the ship to do the re-plating," recalls Barker. "After all, these cylinders are 60 ft.
above the main deck." Running the numbers on detaching the cylinder, Metal Surgery concluded they could cut costs by setting up at the site of the cylinder. And based upon their experience with past brush plating projects, they felt no problem. Exposing a repair crew to a typical Duluth winter presented a major challenge. Considering the need to pre-heat the cylinder for plating and the working location, the repair crew was facing finger-numbing sub-zero weather and high velocity winds accelerated by the height of the work. So instead of taking the cylinder into the shop, Metal Surgery built a shop around the cylinder. In about a week the crew set to work erecting scaffolding and building a heated house to enclose the cylinder and shelter the crew while providing sufficient working room.
The crew spent roughly another week applying copper plating to the damaged areas of the cylinder. Brush plating builds up worn parts to their original specifications by bonding applied metal to the parent metal at the molecular level. Based upon their involvement with a number of critical specialty projects, Metal Surgery has developed techniques to bring this process into the field. Metal Surgery developed water cooled anodes for controlled applicatioi of the plating. This approach stops over heating of the deposited material to pre vent its degradation.
The brush plating process progressive ly restored the plating on the cylind( ram, and once plating was complete the copper areas were hand finished contour. Finally, the surface was flash( with nickel tungsten to acquire hardne and corrosion resistance to its origin specifications.
The following week was spent dis< sembling the housing and scaffold.
