Greetings all,

I am a project engineer overseeing the maintenace and repair of 8 large ocean going ships. Due to economic reasons, the organization I work for will be placing 4 in "deep layup" for an indeterminate period of time. Conceptually, when these ships get reactivated, we will have 30 days to get everything back up into fully operational status.

Notionally, we intend to have all four ships berthed in close proximity with a small M&R staff in place to take care of them.

I have no experience with placing equipment/assets into a long term storage environment, and am looking for any advice for the general types of equipment listed below. Keep in mind, this equipment is in a marine environment, so corrosion protection is high on my list of priorities. Assume no equipment will be removed for storage off site.

My goal is to balance the deactivation and ongoing M&R costs associated with equipment preservation with the reactivation costs, schedule (anticipated 30 days), and unplanned failures that are bound to occur.

Systems that need to be addressed:
Propulsion System (gas turbines, large gearboxes, hydraulic and fuel pumps, babbitt shaft bearings)

Compressed air (piping and compressors)

Potable water (piping, pumps, and tanks)

Sewage (piping, treatment system, holding tanks, pumps, etc.)

Salt Water Cooling (pumps, piping)

Fresh Water Cooling (pumps, piping)

Hydraulic systems (pumps, piping, valve blocks, rams etc. both in the weather and interior to the ship)

Electrical (disel engines, generators, switchboards, trasnformers, motors, automation systems (operator stations))

Salt Water Ballast (pumps, piping, tanks)

Misc. gearboxes (winches, etc.)

Thanks in advance for your help.

Matt,
You sure have an interesting challenge ahead of you. let me make a start, and no doubt others will add their views. My suggestions are embedded in your list, in italics.

quote:

Propulsion System (gas turbines, large gearboxes, hydraulic and fuel pumps, babbitt shaft bearings)
Spade off the compressor inlet and flue gas to stack flanges and Keep the rotors in a low pressure (2" water pressure) dry air or nitrogen atmosphere(dewpoint -10 to -20F); turn the shaft 270 degrees every month. Clean and lubricate all the fuel injection nozzzles and piping especially if you are using heavy fuels. large gearboxes should be filled up with lub oil; if seals are likely to leak fill up just below seal , add nitrogen purge and rotate rotor assembly to wet all part every month. If you can renove the babbit bearings and put in brass sleeve rings do so, if not graphite paste lubricate shafts at babbit.
Compressed air (piping and compressors) Low dew point air/nitrogen purge the system and keep it under 2" water pressure
Potable water (piping, pumps, and tanks) again a low pressure dry anitrogen blanket, after draining out system, will be the most economic way

Sewage (piping, treatment system, holding tanks, pumps, etc.) I have no experience with these

Salt Water Cooling (pumps, piping) drain off sea water and replace with fresh water in as much of the sytem as possible Either a nitrogen blanket or some doping with 9permissible) bactericides may be required. The rest need individual attention depending on their circumstances

Fresh Water Cooling (pumps, piping) Either keep the system running or drain, blanket with nitrogen where possible, paint cooling tower internals etc

Hydraulic systems (pumps, piping, valve blocks, rams etc. both in the weather and interior to the ship) Keep these filled up with hydr. oil, and if possible run the system once a month or so.

Electrical (disel engines, generators, switchboards, trasnformers, motors, automation systems (operator stations)) You will probably need these running from time to time. Apart from cleaning them out initially, the best thing is to keep them operational
Salt Water Ballast (pumps, piping, tanks) as for salt water sytems

Misc. gearboxes (winches, etc.) as before

There will be exceptions to the list suggested above depending on the local situation
I note that you are not addressing Hull corrosion/barnacle issues; these could prove pretty large problems too. The rudder and its actuator need attention as well.

Vee,
Thanks for responding. Your advice jibes up pretty well with the concepts we've been batting around internally and with what I've been able to find on the Web. It's nice to know we're on a reasonable path with this effort.

With repspect to the hull cleaning, barnacles, etc., it would be our intent to throughly clean the hull (and polish the propeller!) using commercial divers if we were to reactivate the ship for an extended amount of time. Additionally, since regulatory bodies require periodic dry dockings, we would also use that opportunity to clean and paint the underwater hull.

Additionally, I lumped the rudder in with the hydraulics, and I agree, periodic movement would be necessary to prevent expensive problems down the road.

Regards,
Matt

By coincidence I was watching one of the Discovery channels last week and they had a special on this. The Navy has two or three fleets mothballed in various states of readiness. The show did a quick pass on what the Navy did to keep ships in sleep mode.

You may be able to find documents on the DoD website in the public domain on what they do. Just an idea.

Aubrey

Although it does not target ocean going ships you may still find the following publication of some assistance.

Guidelines for the Mothballing of Process Plants, MTI Publication No. 34 By R.J. Twigg

Me too wish to mothball my water treatment tanks and piping any cheaper solutions.

Matt,

Did you contact the Military Sealift Command (MSC)? They layup and activate a lot of vessels. I worked on a few that had problems when activated for the 1st Gulf War. I guess if you don't layup and maintain properly you might as well make them into a big offshore reef!

Walt