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USS Freedom (LCS 1) in what is becoming a rare sight - somewhere besides a pier or dry dock. |
The new casualty is related to the incident in late April when ship's force detected a seawater intrusion in the port combining gear. Ship's force suspected a failed reduction gear seawater cooler as the source of the intrusion. At that time the ship had requested that an outside activity (shipyard) be made available to inspect and repair the port combining gear lube oil seawater cooler and either repair or replace the seawater cooler tube bundle.
On Tuesday evening ship's force inspection revealed rust on two of the reduction gear casings. Bearing temperatures remained normal, and downstream lube oil samples remained clear during system operations. The Navy is working to re-clean the sumps with hot oil, replenish filters, and resume operations.
When I heard about the first problem back on April 29th, it was suggested I should probably consult EN 1&C. Good advice, from 4-3 here (PDF).
EFFECTS OF WATER AND ACID IN OIL.—Water in the oil is extremely harmful. Even small amounts soon cause pitting and corrosion of the teeth. Acid can cause even more serious problems. The oil must be tested frequently for water, and periodic tests should be made for acid content. Immediate corrective measures must be taken when saltwater is found in the reduction gear lubricating oil system.Finally, because all I can do is laugh, or cry, at this point, the following talking points on the USS Freedom (LCS 1) deployment to date have been provided by a friend whom shall remain nameless.
Occasionally gross contamination of the oil by saltwater occurs when a cooler leaks or when leaks develop in a sump. The immediate location and sealing of the leak is not enough. Additional steps must be taken to remove the contaminated oil from all steel parts. Several instances are known when, because such treatment was postponed—sometimes for a week or less—gears, journals, and couplings became so badly corroded and pitted that it was necessary to remove the gears and recondition the teeth and journals. Saltwater contamination of the lubricating oil may also cause bearing burnout.
Water, in small amounts, is always present within the lubrication system as a result of condensation. Air which enters the units contains moisture. This moisture condenses into water when it strikes a cooler surface and subsequently mixes with the oil. The water displaces the oil from the metal surfaces and causes rusting. Water
mixed with oil also reduces the lubricating value of the oil itself.
When the main engines are secured, the oil should be circulated until the temperature of the oil and that of the reduction gear casing approximate the engine room temperature. While the oil is being circulated, the cooler should be operated and the gear should be jacked continuously. The purifier should also be operated to renovate the oil while the oil is being circulated and after the oil circulation is stopped until water is no longer discharged from the purifier. This procedure eliminates condensation from the interior of the main reduction gear casing and reduces rusting in the upper gear case and gears.
Generally, lubricating oil will be maintained in good condition if proper use is made of the purifier and settling tanks. However, if the purifier does not operate satisfactorily and does not have the correct water seal, it will not separate the water from the oil. You can check for the presence of water by taking small samples of oil in bottles, and allowing the samples to settle. These samples should be taken from a low point in the lube oil system.
Samples of lubricating oil should be tested at every opportunity for acid, water, and sediment content at a naval shipyard (or other similar activity). With continuous use, lube oil increases in acidity, and free fatty acids form a mineral soap which reacts with the oil to form an emulsion. As the oil emulsifies, it loses its lubricating quality. Once the oil has emulsified, the removal of water and other impurities becomes increasingly difficult. When the formation of a proper oil film is rendered impossible, the oil must be renovated.
Sometimes, when a ship from the reserve fleet is placed back in commission, the rust preventive compound is not removed completely. The residue of this compound may cause serious emulsification of the lubricating oil. Operating with emulsified oil may result in damage to the bearings or the reduction gears. Since it is extremely difficult aboard ship to destroy emulsions by heating, settling, and centrifuging, you must make sure that emulsions do not occur. At the first indication of an emulsion, the plant should be stopped and the oil renovated.
"Due to her reliance on contractor maintenance, combined with additional and unexpected opportunities to repair equipment well before the expected maintenance intervals, FREEDOM is actually stimulating the American marine repair industry. Further, due to the travel costs involved with sending technical support teams from the United States, FREEDOM is further supporting the American airline industry. I don't like to think of things breaking as a bad thing - but rather as an opportunity to support our partners in industry and the American economy writ large."It is going to be very difficult for LCS to prove itself in an overseas deployment if the ship can't get off the bleeping pier.
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