The Machinist’s Mate (MM) rating operated, maintained, and repaired the main propulsion plant — turbines, reduction gears, main steam systems, and the auxiliary machinery that supported propulsion. The engine room and main control were the MM’s primary workspace: spaces wrapped in deteriorating asbestos insulation on every steam line, every piece of auxiliary equipment, and every valve and fitting throughout the propulsion train.
Deposition testimony from Navy Machinist’s Mates in publicly filed asbestos litigation provides direct accounts of asbestos contact as a routine feature of propulsion plant work.
The Engine Room and Main Control Environment
Machinist’s Mates worked in the engine rooms and main control spaces — the aft engineering compartments directly connected to the main shaft. Like the fireroom, the engine room was a heavily insulated, enclosed space, but with a different equipment profile:
- Main propulsion turbines — large high-pressure (HP) and low-pressure (LP) turbine casings lagged with asbestos pipe covering and insulation jackets; turbine glands packed with braided asbestos packing
- Reduction gears — housed in large casings with asbestos-containing joint gaskets and insulation
- Main steam lines — the high-pressure, high-temperature steam supply from the firerooms ran through the engine room on asbestos-covered pipe
- Auxiliary steam systems — feed-water heaters, steam ejectors, condensers, and steam traps throughout the engine room, all with asbestos-containing insulation and seals
- Propulsion pumps — main feed pumps, condensate pumps, and circulating pumps with asbestos gaskets at all flange connections and braided packing in pump glands
- Overhead and bulkhead insulation — deteriorating over the ship’s service life in an enclosed space subject to vibration and heat
Documented Work Activities
Publicly filed deposition testimony from Navy Machinist’s Mates describes the following asbestos-releasing work activities performed as routine duties:
Valve packing and repacking: “That was a machinist mate’s duty to [remove and replace valve packing]” — deposition testimony directly attributes valve packing work to the MM rating. Removing old asbestos packing from valve glands with picks and scrapers, then cutting and installing new asbestos packing, was a routine daily task in the engine room. “Packing from glands of pumps and valves” is specifically documented in publicly filed MM testimony.
Pump maintenance: “It was common for me to repair pumps, valves…” — MM deposition testimony describes pump disassembly including removal of asbestos packing from pump glands and asbestos gaskets from flange connections. Main feed pumps, condensate pumps, and circulating pumps required regular gland repacking.
Valve and insulation maintenance alongside Pipefitters: Publicly filed testimony describes “Pipefitters and Machinist’s Mates as they removed [insulation]” — establishing that MMs worked side by side with insulators during insulation removal, with direct and bystander asbestos exposure.
Watch standing in main control: “As a Machinist’s Mate serving aboard ship, [watch duties included]…” — watch-standing MMs stood throttle watch in main control, surrounded by the same deteriorating insulation as the engine room.
Machinist’s Mate Class A School: “Machinist’s Mate Class A School” is referenced in the litigation corpus — documenting that MM training specifically prepared ratings for propulsion plant maintenance work involving the equipment and materials described above.
M Division Structure
“The M Division is made up of the machinist’s mates” — the engineering department’s M Division encompassed the MM rating, working alongside Boiler Tenders (B Division) in the engineering plant. Supervision of MMs by Chief Machinist’s Mates is documented in publicly filed records covering carriers, cruisers, and destroyers.
“BTs and machinist’s mates also in his [the engineering officer’s] charge” — documented organizational structure placing both BTs and MMs under engineering department supervision in the same plant.
Ships and Equipment
Machinist’s Mates are documented in publicly filed asbestos litigation aboard:
- Aircraft carriers (CV/CVA/CVS/CVN) — Westinghouse and General Electric geared turbines; 4 turbines developing 150,000–280,000 shaft horsepower
- Cruisers (CA/CG) and destroyers (DD/DDG) — Westinghouse and GE turbines; propulsion systems with same insulation pattern
- Amphibious assault ships (LPH/LHA/LHD) — steam or later gas-turbine propulsion
- Destroyer tenders and submarine tenders — MMs maintained the ship’s own propulsion plant as well as serviced visiting combatants
Equipment regularly maintained by Machinist’s Mates with documented asbestos content:
| Equipment | Manufacturers | Asbestos source |
|---|---|---|
| Main propulsion turbines | Westinghouse, General Electric | Turbine casing insulation jackets, gland packing |
| Reduction gears | Westinghouse, GE, Falk | Housing gaskets, lubricating oil system seals |
| Main feed pumps | Worthington, Warren, Sturtevant, De Laval | Pump packing glands, flange gaskets |
| Steam valves (engine room) | Crane Co., Atwood & Morrill, Leslie Controls, Walworth | Stem packing, flange gaskets |
| Steam traps | Yarway, Armstrong | Internal gaskets |
| Distilling plants | Griscom-Russell, Aqua-Chem | Tube bundle gaskets, pipe covering |
| Oil purifiers | De Laval | Internal gaskets, pipe connections |
Documented Crew — Ratings and Exposure Periods
Publicly filed deposition testimony from Navy Machinist’s Mates documents:
- Machinist’s Mate (E-4 through E-7) — served aboard carriers, cruisers, and destroyers; documented valve packing, pump repair, and propulsion turbine maintenance as routine duties involving asbestos-containing materials
- Chief Machinist’s Mate — supervised M Division personnel; present during all maintenance periods; documented in publicly filed records with specific ship assignments
- Motor Machinist’s Mate — variant rating (diesel-electric vessels); documented similar gasket and packing exposure in diesel propulsion plants
VA and Legal Options
The Machinist’s Mate rating is among the best-documented in the Navy asbestos litigation record. The combination of MM rate code, ship assignment, and propulsion plant maintenance duties creates a strong VA presumptive exposure claim.
Key documents:
- DD-214 Block 11 — primary specialty showing MM rate
- Ship assignments from DD-214 duty stations or NARA muster rolls
- Diagnosis — mesothelioma, asbestos-related lung cancer, asbestosis, or pleural disease
Civil claims against the manufacturers of turbines, pumps, valves, gaskets, and pipe insulation installed in propulsion plants — including Westinghouse, Crane Co., Warren Pumps, John Crane, Garlock, and Kaylo — are supported by the documented MM exposure pattern.
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Exposure documentation derived from publicly filed asbestos litigation records including deposition testimony from Navy Machinist’s Mates and Bureau of Ships technical manuals. This does not constitute legal or medical advice.