The GUPPY (Greater Underwater Propulsion Power) conversion program modified WWII-era Balao and Tench class fleet submarines between 1947 and 1954, improving their submerged performance by streamlining the hull, adding a snorkel system, increasing battery capacity, and upgrading propulsion machinery. Approximately 52 fleet submarines received GUPPY modifications in three major conversion types (GUPPY I, GUPPY II, and GUPPY III). GUPPY submarines served throughout the 1950s-1970s in the Atlantic and Pacific Fleets as the backbone of the Cold War conventional submarine force before being replaced by nuclear submarines. Crew members served in the WWII-era hulls with asbestos insulation on diesel engine exhaust systems and throughout the interior construction from the original 1943-1945 construction.

Diesel Engine Room and Asbestos

GUPPY submarines retained the WWII-era Fairbanks-Morse or General Motors diesel engines as the basis for GUPPY diesel-electric propulsion:

  • Diesel exhaust system insulation — the diesel engine exhaust systems on GUPPY submarines used asbestos insulation on exhaust piping, exhaust silencers, and associated exhaust components in the engine room. Machinist’s Mates and Electrician’s Mates performing diesel engine maintenance worked in proximity to asbestos-insulated exhaust components throughout their engineering tours
  • Engine room auxiliary equipment — auxiliary equipment in the engine room — freshwater coolers, heat exchangers, and associated piping — used asbestos-containing gaskets and packing in WWII-era and postwar construction
  • Engine room overhead and structural insulation — the engine room overhead and bulkhead construction in WWII-era submarine hulls used asbestos-containing materials in structural insulation and in mechanical systems serving the engine room

Snorkel System and GUPPY Modifications

The GUPPY conversion added the snorkel mast system allowing diesel engine operation while submerged at periscope depth:

  • The snorkel induction and exhaust system piping added during GUPPY conversion used insulation and sealing materials from the late-1940s and early-1950s construction period — potentially including asbestos insulation on snorkel exhaust piping components

Interior Construction Asbestos

GUPPY submarines retained the original WWII-era interior construction from the Balao and Tench class hulls:

  • Asbestos pipe covering on steam system piping (battery ventilation, auxiliary heating) and on galley steam equipment aboard GUPPY submarines in the original 1943-1945 construction
  • Asbestos-containing deck tile in crew berthing and working spaces in the WWII-era interior construction

VA Claims for GUPPY Submarine Veterans

VA presumptive service connection under 38 CFR § 3.309(d) covers asbestos exposure aboard conventional submarines. Engineering ratings — Machinist’s Mates, Electrician’s Mates — who served aboard GUPPY-converted submarines during the 1950s-1970s and have since been diagnosed with mesothelioma, asbestosis, or asbestos-related lung cancer may qualify for VA disability benefits.

Product & Manufacturer Reference

The asbestos-containing products documented on U.S. Navy vessels and at shipyards are catalogued by manufacturer on AsbestosIndex. These records cross-reference which companies supplied which materials and to which facilities.

Pipe Covering & Block Insulation Thermal insulation applied to steam lines, valves, and equipment in engine rooms and fire rooms Marine Products Insulation, gaskets, and packing products specified for naval and commercial marine applications Boilers & Steam Equipment Boiler manufacturers and insulation products — central to the fire room exposure pathway Gaskets & Packing Sheet and ring gaskets used throughout piping flanges, valve bonnets, and pump housings Electrical Products Wire insulation, switchgear arc chutes, and panel liners used throughout electrical spaces Full Product Index Search all 200+ manufacturers and 1,500+ documented asbestos products on AsbestosIndex™

Navy Ratings Most Exposed to Asbestos Aboard GUPPY Submarine Conversions

The U.S. Department of Veterans Affairs and the public asbestos litigation record document that the following Navy ratings worked routinely in spaces where ACM was installed, maintained, ripped out, and replaced:

VA Presumptive Benefits — No Filing Deadline

The U.S. Department of Veterans Affairs recognizes mesothelioma, asbestos-related lung cancer, asbestosis, and pleural disease as conditions presumed to be service-connected for Navy veterans with documented asbestos exposure under 38 CFR § 3.309(d). No statute of limitations applies to VA disability compensation claims.

Available benefits may include monthly disability compensation, Dependency & Indemnity Compensation (DIC) for surviving spouses, priority VA healthcare enrollment, and Special Monthly Compensation for severe cases. Parallel claims against the asbestos bankruptcy trust funds established by the manufacturers of these products do not reduce VA compensation.

How to file a VA disability claim: VA claims are filed directly with the U.S. Department of Veterans Affairs — not with a law firm. Start at VA.gov › Hazardous Materials Exposure, call 1‑800‑827‑1000, or get free help filing from a Veterans Service Organization: DAV, VFW, or American Legion.

VA Claims Guide on This Site › Compare: VA vs. Civil Lawsuit

Source notes: equipment-manifest entries (where shown) are sourced from public-record BUSHIPS (Bureau of Ships) documentation, NARA archives, and the public asbestos litigation record. Manufacturer attributions link to documented asbestos-product histories on AsbestosIndex.com where available. Nothing on this page constitutes medical or legal advice.