Ramage, when fully loaded, displaces 8,943 tons, and its four engines generate 100,000 shaft horsepower. However, for the majority of the equipment the ship requires only four oils and several types of grease. (Contrast that with the 37 oils and greases stocked aboard the Carnival Legend, an 81,600-hp, 88,500-ton cruise ship profiled in last months LubesnGreases.)

Why such a Spartan inventory of lubricants? Its a logistical decision, explains Rich Dempsey, division director of the Fuels and Lubricants Non-Metallic Materials Engineering Division for the Naval Sea Systems Command at the Washington D.C. Navy Yard. Years ago, he points out, there were many more lubricants than now and a lubricant reduction program was undertaken. Two issues were paramount – to ensure the safety of sailors and the integrity of the equipment. The result was that the number of lubricants was substantially reduced, to the absolute minimum. We try to get the oil to serve as many functions as we can, but we have to go to the various equipment manufacturers to ensure that an oil can service their equipment.

Riggs makes the same point from his operational position. With mainly four types of oils to service the whole ship we can obtain them from a lot of places when we need them, he says. When were deployed it can come from an oiler, another warship or from a supply port. They are, in effect, universal oils.

Dempsey explained the MIL SPEC acquisition process, using MIL-PRF-17331J as an example. Part 1 of this specification defines the product scope, for use in main and auxiliary turbines and gears, air compressors, and certain hydraulic equipment as well as general mechanical lubrication. Part 2 lists the applicable federal and private technical documents, which for this specification includes 27 specific ASTM test methods. Part 3 lists the technical requirements including 20 physical and chemical requirements and test methods. Viscosity, for example, is defined by the well-known and the product is then purchased from this list by commodity managers in the military central procurement offices, either bulk or packaged, through the normal acquisition process. The system works, he pointed out, and many of our MIL SPECs are also used in other navies – for example, 17331J has a NATO symbol of O-250.

Dempsey added, Engineering judgment does come into play at times when the product is delivered for use. If a single specification for a relatively minor measure – the acid number for example – is off by a little bit, we may approve the product, he said.

UP TO SPEC

For decades the military has obtained a large part of its supplies, including lubricants, through the military specification (MIL SPEC) system. The largest volume of oil on Ramage by far is a fluid meeting Military Specification MIL-PRF-17331J. This oil is used to lubricate the two main reduction gears, with sumps of 1,500 to 1,700 gallons, which transfer the power of the gas turbine engines to the propeller shafts. The same oil also lubricates the ships line-shaft bearings (each with its own sump) and is pumped down the shafts to serve as a hydraulic fluid to move the variable-pitch propeller blades. ASTM D-445 [test method]. Part 4 defines the verification processes to insure quality control, which includes inspection of manufacturing facilities and conformance sampling throughout the full custody chain, from production to final delivery. Packaging, bulk or containers, is spelled out in the final section.

When a company wants to supply this product to the military it will conduct all the tests, and this office then reviews the test data to ensure that it meets the test limits, Dempsey continued. When we approve the product it goes on a Qualified Product List, QPL,

A perspective from the supply side of the MIL SPEC system comes from Joe Zacharzuk, sales manager for marine lubricants for U.S. government contracts at ExxonMobil Lubricants & Specialties. Prior to his current position, Zacharzuk was a U.S. Navy officer and his 25-year career included command of a Navy warship.

We participate in the MIL SPEC procurement process and supply the high-tech synthetic oil for gas turbines, he said. Its a very competitive market and a small but important part of our business. The MIL SPEC procurement process has a long history. Theres been some movement over the last decade to modify this system toward the use of more off-the-shelf commercial products, to meet the lubrication requirements of some state-of-the-art equipment.

Todays lubricant technology typically meets or exceeds MIL SPEC criteria for specified equipment, Zacharzuk observed. This would be especially important to the Navy as it continues to build its newest ship classes. Acknowledging the limitations on the number of lubricants a warship can carry, ExxonMobil believes that the Navy would experience an increase in equipment reliability and a corresponding decrease in repair costs by using equipment-builder-approved commercial lubricants formulated specifically for the respective machinery applications.

PUT TO THE TEST

In addition to its formal designation as MIL SPEC MIL-PRF-17331J, Ramage’s principal oil is stocked as Military Symbol 2190 TEP, which is how Lt. Riggs refers to it. This oil is used on all ships in the Navy with reduction gears, he notes. It has two uses: as a lubricant and coolant in the main reduction gear, and as a hydraulic fluid to move the variable pitch propellers.

The quality of the oil is maintained by running it through a centrifugal purifier for a minimum of 12 hours a day on the reduction gear oil and four hours a day on the variable-pitch [propeller] oil. We normally don’t have to change it unless there’s a major problem such as a bearing failure or water intrusion, since we use salt water to cool the lubricant.

Daily samples are also taken whenever the equipment is operating, to verify the quality of the lube oil, Riggs continued. The daily visual test checks for the presence of water and particulate matter. As long as the visual is satisfactory, we leave it in the sump. We have 7,000 gallons of bulk storage capacity on board and are required to maintain at least one complete sump change for each of the two sumps.

Assisting Riggs is Petty Officer 2nd Class Anthony Cass, with four years in the Navy. I’m assigned to the oil lab and that’s where we conduct the various tests on the oil, he said. If a contaminant does appear in the oil, we conduct on-board testing as well as send it to a shore lab for analysis.

OIL ABOARD

There are three other main oils used on the ship.

MIL-PRF-23699, a fully synthetic aircraft oil is used to lubricate the four main propulsion gas turbines, and for its electrical generators. Lt. Riggs explains, Very little oil is necessary for the gas turbines, and we inventory it in quart containers. In addition to the propulsion gas turbines, the ship has three smaller Allison gas turbines to generate all the ships electric power. Each engine produces 4,000 amps of power and is also lubricated with 23699.

MIL-PRF-9000H, a monograde SAE 40 engine oil, lubricates the Volvo 190 hp diesel engines that power the two rigid hull inflatable boats used for going ashore, in the event of a man overboard or other at-sea tasks. (Unlike a cruise ship, a warships lifeboats are inflatable and maintained in containers that look like barrels; they’re inflated automatically or by the crew when needed.)

MIL-PRF-17672D (Military Symbol 2135-TH) rounds out the onboard oil inventory – a hydraulic fluid which moves the ships two rudders. Rudders are controlled by hydraulic rams on either side. A pump, which runs all the time on zero stroke, comes on-stroke and generates the hydraulic pressure which moves the piston and then the rudders.

Then there’s the general grease, MIL SPEC DOD-G-24508A, which is used for the majority of grease applications. Some pieces of equipment have special needs for grease applications and Ramage carries those accordingly. Very little grease is used, reports Riggs.

Navy warships face plenty of obstacles and threats – the USS Cole, home-ported at a nearby pier, provides a chilling example – and lubricant quality has to be assured both for the safety of the crew and to maintain high operational status when deployed.

That mission is always foremost, and Dempsey in Washington, D.C., proudly notes, I am not aware of any equipment failure or problem which was traced to a lubricant.