Oiling system design and contamination, leading to engine crankshaft bearing failures and crankshaft damage, continue to plague the U.S. Navy's latest LPD17 series of amphibious transport warships. A new report has now drawn attention to crankshaft bearing failures on the USS San Antonio, the fourth of five to be laid up due to main bearing and engine damage caused by contaminants, faulty lubrication systems, and the crews' inability to identify the bearing problem 5251R9N7 before it became severe.

article: Next-gen U.S. warships plagued by bearing failures
The JAGMAN report, commissioned by the U.S. Fleet Forces Command, blamed poor workmanship, "significant engineering problems," and "numerous unacceptable conditions" involving most of the systems and construction of the LPD17 series, and the San Antonio in particular. As delivered, the San Antonio suffered from, "thousands of construction deficiencies."

The ships are outfitted with four massive Fairbanks Morse (a division of EnPro Industries) Colt-Pielstick PC 2.5 STC diesel propulsion units. Each 16-cylinder engine weighs 84 metric tons, and is rated at just over 10,000 brake horsepower at 520 RPM. The cranks sit in nine massive main bearings, fed by high-volume externally pressurized oiling systems. In the LPD17 ships, two engines feed one reduction gearbox and prop. Engine rooms and lubrication systems are entirely automated.

Colt-Pielstic PC 2.5 STC

Built by Northrop Grumman Shipbuilding, five of the new ships have been delivered and are in and out of service; four remain to be built. Four of the five delivered have experienced crankshaft bearing failures -- San Antonio, Mesa Verde, Green Bay, and New York -- with consequential extensive damage to the massive diesel engine crankshafts. Only the USS New Orleans has not experienced crank bearing failure. Once the bearings are damaged, crank vibrations are set up which can quickly destroy the crank, engine reciprocating parts, gearbox, and mounting structure, as happened with the USS New York.

The flagship USS New York, built with 7.5 tonnes of steel from the World Trade Center, experienced crank bearing failures so severe that the vibrations forced a humiliating low-power return to dry dock during its first week-long voyage. During teardown, the New York's crank bearing failures were found to be so severe that one of the massive cranks was bent by the resulting vibration; bent crankshafts are extremely rare in a nine main bearing arrangement.

Crank misalignment and the resulting destructive vibrations have apparently been set up in the engines because bearings were contaminated by lubricant debris up to 40 microns. While lubricant debris is a universal byproduct of wear and the combustion process, the 40 micron debris was hard enough to damage the bearings and the crank and cause crank misalignment.

Northrup-Grumman is blaming the shipyard for contaminating the oiling systems as they were being built. They suggest sloppy work, welding slag, and debris from sandblasting are the culprits. However, stainless steel was reportedly the primary lube contaminant found in the Mesa Verde and Green Bay engine bearings last year. The ships had the lubricant flushed, and the piping replaced between the engine and the main filter strainer.

USS New York LPD21

The flagship of the series, USS New York, gained international fame with its construction incorporating with 7.5 tons of steel from the World Trade Center forged into her bow.


As in those previous situations, the USS San Antonio's four diesel engines have now been discovered with have badly damaged bearings and cranks due to extensive contamination in the ship's oiling system. Those contaminants got into the oiling system, said the report, during construction. The culprits were primarily poor welds and shoddy welding practices, but the report also blamed poor lubrication system design and engineering.

Exacerbating the built-in lubricant contamination problem was the fact that the sailors responsible for the oiling systems had not been properly trained to recognize and/or deal with lubricant contamination. The Navy said action will be taken against those responsible for those, "training and maintenance deficiencies," citing the crews' over-reliance on and failure to understand the automated engine room systems and condition monitoring systems.

The 62 page report focuses on the entire program, and the USS San Antonio specifically.

Originally budgeted at $800 million, the USS San Antonio has now cost U.S. taxpayers more than $1.8 billion, and is docked as unseaworthy in Norfolk, Virginia. Its last prolonged period in the water ended in March 2009.

The first of the LPD17 series, San Antonio is 25 long tons, 684 feet long, 105 feet wide, has a crew of 360 and can carry 700 more troops. LPD17 streamlined construction is designed to help it move faster, be less visible, and be flexible enough for a variety of duties.

Most Navy observers now say the LPD17 series problems began on the drawing board -- LPD17 was the first warship to be designed entirely by 3D CAD computer software. A new company, Avondale, beat out established competitors entirely due to their low-cost use of software to design the ships. Unfortunately, the software was "immature" and could not handle the thousands of construction and systems changes which necessarily occur during the development of a $1 billion warship. And Avondale's annual personnel turnover ran at nearly 40%. A year later, Litton Ingalls, an experienced shipbuilder, bought Avondale expecting to be able to turn the project around but could not. San Antonio and the next ship in the series, New Orleans, were also plagued by substandard construction methods and substandard materials, nonworking ventilation systems, massive electrical system deficiencies, and others.

Although the ship's problems have now been traced back to its first design stages, the first physical manifestation were oil leaks and what later became massive damage to the San Antonio's engine bearings during its maiden voyage in October 2008. It was delivered and commissioned in 2006 but had failed a 2007 inspection so did not have sea trials until 2008.

During that voyage, the engines' externally plumbed and pressurized oiling system leaked to the extent it had to spend three weeks in Bahrain undergoing repairs. Ultimately, 80% of the oiling system had to be replaced due to faulty welds, contamination in the system, and basic design and installation errors.

However, the damage to the engine bearings had already begun, as the contaminants introduced to the oiling system during construction were so extensive that they were not properly controlled by the filtration system.

Repairs to the San Antonio began only after its bearing failures were examined during the JAGMAN investigation. In December 2009, Fleet Forces Command's Admiral John Harvey ordered a Manual of the Judge Advocate General investigation (JAGMAN). The investigation was led by the Navy's Chief Engineer, Rear Admiral Tom Eccles.

There are apparently no current status reports on repairs to the New York's engines; three of the four need repairs and new bearings, and one requires a crankshaft.

Currently, the San Antonio is in Norfolk dry dock. To access and replace the massive engines' bent crankshafts and failed bearings, Navy engineering crews are cutting large holes in the San Antonio's decks. This is reportedly the first time the Navy has ever cut access holes into any of its vessels in order to service the crankshaft and bearings.