Evidence
10 evidence entries recorded; each entry has a stable permalink (#ev-1 … #ev-10).
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[1]research packet 895-packet.md [other_primary]
- Finding type
- vessel_history
- Finding
- Identity packet verdict: VERIFIED
- Verification
- verified
- Role
- supporting
- Documentation level
- ship_specific
- Evidence ID
- uss-pc-481-pc481-pkt-895-packet-md
-
[2]NavSource Online: Submarine Chaser Photo Archive, PC-481 (verified live 2026-10-03) [other_primary]
- Locator
- NavSource 12/010481.htm - header narrative and specifications block
- Finding type
- vessel_history
- Finding
- Documented for this hull: 'PC-461 Class Submarine Chaser: Laid down, 3 February 1942 by the Defoe Shipbuilding Co., Bay City, Michigan; Launched, 31 March 1942; Commissioned USS PC-481, 24 April 1942. During World War II, PC-481 was assigned to the European theater of operations. Decommissioned 16 June 1944 and transferred to France at Casablanca, Morocco as L'Effronté (W 42); Sunk as a target by the French, 29 April 1953; Struck from the Navy Register 2 May 1953.' Call sign Nan-Baker-Nan-Baker. Specifications: displacement 450 t.; length 173'8"; beam 23'; draft 10'10"; speed 20.2 kts.; complement 65; armament one 3"/50 dual purpose mount, one single 40mm mount, three 20mm guns, two rocket launchers, four depth charge projectiles, two depth charge tracks; propulsion two 2,880bhp General Motors 16-258S diesel engines (Serial No. 6341 and 6344), Farrel-Birmingham single reduction gear, two shafts. Page states 'There is no DANFS History currently available for PC-481.'
- Verification
- verified
- Role
- context
- Documentation level
- ship_specific
- Accessed
- 2026-10-03
- Study period
- 1942-1953
- Population
- Defoe construction trades (1942); USN crew 1942-44 (complement 65); French crew 1944-53
- Limitations
- NavSource is a volunteer secondary compilation, not a primary registry - its milestones generally track Navy records but carry no DANFS backing for this hull. The 'two 2,880bhp' line conflicts with sister PC-471's NavSource page (1,440bhp each; the class-standard pair totals 2,880 bhp) - carried as published with the variance logged in gaps. No asbestos or material content.
- Atlas source
- true
- Evidence ID
- ev-uss-pc-481-pc481-01
-
[3]shipbuildinghistory.njscuba.net (Tim Colton), 'Sub Chasers Built During WWII (SC, PC, PCE, PCER, PCS)' - PC-481 row and program notes (verified live via firecrawl 2026-10-03) [other_primary]
- Locator
- pc2 table, PC-480/481/482 rows; program introductory notes
- Finding type
- vessel_history
- Finding
- Build-table row for this hull: 'PC-481 | Defoe SB | Bay City MI | 463 | 173 | 24 Apr 1942 | to Free French 1944 as L'Effronte (W-42), sunk as target 1953' (columns: builder, location, LDT, LOA, delivered, notes). Program context: 973 sub chasers and related craft built during WWII by 74 boatbuilders/yachtbuilders; 'The PCs were 173-foot steel Patrol Craft, primarily used for coastal duties'; more than 400 transferred to allied navies, the Free French the second-largest recipient (88 boats across the SC/PC/PCE/PCS program).
- Verification
- verified
- Role
- context
- Documentation level
- ship_specific
- Accessed
- 2026-10-03
- Study period
- 1941-1945 (build program); 1942-1953 (hull)
- Population
- Defoe construction trades (1942)
- Limitations
- Secondary compilation (Colton's shipbuilding reference) - corroborates NavSource milestones; the 'delivered' column reads 24 Apr 1942 where NavSource reads commissioned the same date. Its 463-t LDT figure differs from NavSource's 450 t and navypedia's 325 std/430 full - displacement figures vary by convention and are logged in gaps. No asbestos content.
- Atlas source
- true
- Evidence ID
- ev-uss-pc-481-pc481-02
-
[4]uboat.net Allied Warships, USS PC-481 (PC-481) - build data, commanding officers, wartime event log (verified live 2026-10-03) [other_primary]
- Locator
- uboat.net ship/8503.html - warship data block, command table, notable-events log
- Finding type
- vessel_history
- Finding
- Service record for this hull: ordered 26 December 1940; Defoe Shipbuilding Co., Bay City; laid down 3 Feb 1942, launched 31 Mar 1942, commissioned 24 Apr 1942, end of U.S. service 16 Jun 1944; 'Transferred to France on 16 June 1944 being renamed L'Effronté. Used and sunk as target by the French Navy on 29 April 1953.' Commanding officers: Charles Buck Henriques USNR (24 Apr 1942 - Feb 1943); Duane Rice Stoneleigh USNR (Feb 1943 - 3 Oct 1943); Lt. Nile W. Roeder USNR (3 Oct 1943 - 16 Jun 1944). Event log documents Casablanca-based convoy escort June 1943 - May 1944 (OS/KMS, SL/MKS and UGS/GUS series - e.g., Casablanca section escorted 13 Jun 1943 with PC-480 under Stoneleigh; SL 142 escort join-up 12 Dec 1943 with PC-480 and PC-482; departures with PC-474/PC-475 through 15 May 1944). On 11 April 1943 PC-481 with PC-471 picked up 64 men from the U.S. Liberty ship Matt W. Ransom after she struck mines laid by U-117 off Casablanca (33°55'N, 07°52'W) in convoy UGS-6A.
- Verification
- verified
- Role
- context
- Documentation level
- ship_specific
- Accessed
- 2026-10-03
- Study period
- 1942-1944 (U.S. service)
- Population
- USN crew (complement ~65) 1942-44; Casablanca convoy-escort population
- Limitations
- uboat.net is a specialist secondary database compiled from convoy/escort records - not a primary register; commanding-officer names in event captions occasionally conflict with the command table (e.g., a Feb 1944 escort is captioned 'Lt. D.W. Hunter' though the table has Roeder in command; a convoy-narrative line reads '8 November 1944' inside an unambiguously November 1943 sequence - treated as a misprint, not a post-transfer U.S. operation). No asbestos content.
- Atlas source
- true
- Evidence ID
- ev-uss-pc-481-pc481-03
-
[5]Drevas v. United States, 58 F. Supp. 1008 (D. Md. 1945) (Chesnut, J.) - published opinion (salvage claim by a Matt W. Ransom crewman) [court_record]
- Locator
- 58 F. Supp. 1008, findings of fact (April 11, 1943 casualty recital)
- Finding type
- historical_record
- Finding
- A published federal opinion judicially documents the casualty this hull responded to: on 11 April 1943 at about 3:20 p.m., roughly 50 miles off Casablanca, the Liberty ship Matt W. Ransom 'was hit by a submarine torpedo or struck a mine' (the U-117 field per uboat.net) - a 14 x 15 ft hole in the starboard bow, holds 1 and 3 flooded, all hands ordered into lifeboats; the master and volunteers later reboarded and brought her into Casablanca. The libelant's salvage claim was denied as a matter of law (crew salvage barred absent extraordinary circumstances). uboat.net records PC-481 and PC-471 picking up the 64 men in the lifeboats.
- Verification
- verified
- Role
- context
- Documentation level
- context_only
- Accessed
- 2026-10-03
- Study period
- 1943 (event); 1945 (opinion)
- Population
- Matt W. Ransom ship's company (77 total per the opinion; 64 taken off per uboat.net)
- Limitations
- The opinion does not name PC-481 or any rescuing vessel - the hull's role rests on uboat.net's event log. It is not asbestos litigation (a salvage-award dispute); included as primary-record corroboration of the casualty event only. Nothing about materials aboard either vessel.
- Atlas source
- true
- Evidence ID
- ev-uss-pc-481-pc481-04
-
[6]fringant.net (French Navy veterans' historical site), L'Effronté ex-PC-481 fiche - French-service record transcribed from Marine Nationale documents (verified live via firecrawl 2026-10-03) [other_primary]
- Locator
- fringant.net/pageleffronteus.htm (ship fiche) and pagepcus.htm (1 Jan 1946 order-of-battle table)
- Finding type
- vessel_history
- Finding
- French-service record for this hull (ex-PC-481, L'Effronté): 'Mis sur cale: 3 février 1942; Chantier: Defoe Shipbuilding Co - Bay City MI; Lancement: 31 mars 1942; Admis au service actif: 24 avril 1942 / 16 juin 1944.' Successive assignments: 16 June 1944 Casablanca (3ème division d'escorteurs); 1948 Saïgon (fmeo - Forces maritimes d'Extrême-Orient); April 1951 Toulon; April 1952 Saïgon (fmeo); 1953 Toulon. Last colors ceremony 1953; 'Condamné le 2 mai 1953; Coulé en méditerranée en 1953' (condemned 2 May 1953; sunk in the Mediterranean 1953). Hull numbers listed: W 42, P 623, with W 34 and W 24 marked uncertain. The companion PC-US page places W 42 L'Effronté in the 11ème division d'escorteurs, Comar Casablanca, réserve normale, in the Marine Nationale order of battle at 1 January 1946, and notes 43 PCs were ceded to France serving from 1944.
- Verification
- verified
- Role
- context
- Documentation level
- ship_specific
- Accessed
- 2026-10-03
- Study period
- 1944-1953
- Population
- French crew 1944-53, incl. Indochina deployments (Saïgon 1948, 1952)
- Limitations
- Association transcription of French naval documents (AAMM/escorteurs heritage site), not the archives themselves - pennant sequence is marked uncertain on the page itself (W 34?, W 24?). Its 'condemned 2 May 1953' matches the Navy Register strike date, and 'sunk Mediterranean 1953' matches NavSource/uboat's 29 April 1953 target sinking; sequence (sunk 29 Apr vs condemned 2 May) is carried as documented. No asbestos content.
- Atlas source
- true
- Evidence ID
- ev-uss-pc-481-pc481-05
-
[7]navypedia.org, 'L'EVEILLÉ coastal escorts (1942-1944 / 1944-1951, 1944)' - French Navy table for ex-U.S. PCs incl. L'Effronté (ex-PC481); class technical data (verified live 2026-10-03) [other_primary]
- Locator
- navypedia fr_es_pc.htm - L'Effronté table row, project history, technical data block
- Finding type
- vessel_history
- Finding
- French-Navy table row: 'L'Effronté (ex-PC481) | W34, 1945- W42 | 185 | Defoe, Bay City, USA | 2.1942 | 31.3.1942 | 4.1942 // 6.1944 | BU 5.1953' - i.e., pennant W 34 at transfer, W 42 from 1945; Defoe yard hull no. 185; U.S. commission 4.1942, French service from 6.1944; disposed ('BU') May 1953. Project note: 'US-built 173ft PC-type patrols, transferred to France by lend-lease in 1944.' Class technical data: 325 t standard / 430 t full; 2 General Motors diesels, 2,880 hp, 2 shafts, ~20 kt; complement 59-65.
- Verification
- verified
- Role
- context
- Documentation level
- ship_specific
- Accessed
- 2026-10-03
- Study period
- 1944-1953
- Population
- French crew 1944-53
- Limitations
- navypedia is a secondary reference - corroborates NavSource milestones and adds yard hull no. 185 plus the W34->W42 pennant change (NavSource shows W 42 only). 'BU 5.1953' compresses the April-29 target sinking and May-2 striking into a disposal month. No asbestos content.
- Atlas source
- true
- Evidence ID
- ev-uss-pc-481-pc481-06
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[8]Era inference built on: NavSource PC-461 class index ('The 173 foot World War II constructed PC was steel hulled, twin diesel propelled'); NavSource PC-481 spec block (twin GM 16-258S diesels); shipbuildinghistory class notes (173-ft steel patrol craft); navypedia class technical data (2 GM diesels); WWII-era U.S. Navy construction practice (GAO HRD-80-2, ev-08) [other_primary]
- Locator
- NavSource 12/01idx.htm class header; NavSource 12/010481.htm spec block; shipbuildinghistory pc2 notes; navypedia technical data
- Finding type
- asbestos_application
- Finding
- A 173-ft steel-hulled diesel patrol craft built in early 1942 sits squarely inside the U.S. Navy's asbestos era; era-standard applications aboard a small steel combatant of this type were machinery and exhaust lagging, thermal insulation, gaskets, valve packing, electrical insulation, and deck covering. As a twin-diesel vessel she carried no steam plant - the boiler/turbine lagging pathway of steam vessels does not apply, but diesel exhaust lagging, machinery insulation, and the small-ship confined-space dynamic apply.
- Verification
- inferred
- Role
- supporting
- Documentation level
- class_or_era
- Accessed
- 2026-10-03
- Study period
- 1942-1953
- Population
- Defoe construction trades (1942); USN crew 1942-44; French crew 1944-53; French disposal crews 1953
- Limitations
- Class/era inference only - no hull-specific insulation survey, material list, construction specification, or work package located for PC-481. Names era-standard applications, not confirmed installed materials. No quantity, no manufacturer attribution. Diesel plant - no boiler/turbine lagging claim.
- Atlas source
- true
- Evidence ID
- ev-uss-pc-481-pc481-07
-
[9]GAO, Navy Efforts To Protect Workers From Asbestos Exposure, HRD-80-2 (Oct 18, 1979) [gao]
- Locator
- GAO product page HRD-80-2 (full text blocked, HTTP 403)
- Finding type
- gov_survey
- Finding
- GAO documented that the Navy used asbestos insulation extensively aboard ships and did not begin substituting alternative insulation materials until the early 1970s - spanning this hull's construction (1942), U.S. service (1942-44), and French-service era (1944-53).
- Verification
- verified
- Role
- context
- Documentation level
- class_or_era
- Accessed
- 2026-10-03
- Study period
- 1979
- Population
- Navy shipyard workers; asbestos program review
- Limitations
- Program-level documentation; supports era context only, not any fact specific to this hull or to Defoe Shipbuilding practice. Full text not retrieved (gao.gov returns HTTP 403 to automated fetch, confirmed 2026-10-03) - content via product-page description.
- Atlas source
- true
- Evidence ID
- ev-uss-pc-481-pc481-08
-
[10]Batch-7856 search ledger (this record): NavSource ship page and PC-461 class index; shipbuildinghistory build table; uboat.net warship log; navypedia and fringant.net French-service pages; Justia (Drevas); NHHC/DANFS check; NVR check; NARA deck-log lead; GAO product page; CourtListener base queries; secondary web litigation sweep [other_primary]
- Locator
- search_ledger rows sl-uss-pc-481-pc481-01 through -12
- Finding type
- historical_record
- Finding
- No qualifying ship-specific asbestos record located: no asbestos survey, abatement contract, hazmat disclosure, insulation specification, or verified litigation naming USS PC-481 was found in the public sources searched. There is no DANFS entry for this hull (NavSource states 'There is no DANFS History currently available for PC-481' and the HyperWar/ibiblio DANFS-derived PC index lists PC-480-82 as a group without per-hull pages). The only 'asbestos aboard' material surfaced is law-firm marketing content (mesothelioma.net, mesotheliomalawyercenter.org, mesowatch.org, mesothelioma.com Defoe-shipyard pages) asserting asbestos at the builder generally without hull-level sourcing - excluded by source policy. CourtListener base-query status is recorded in the search ledger.
- Verification
- verified
- Role
- negative_finding
- Documentation level
- ship_specific
- Accessed
- 2026-10-03
- Study period
- 2026-10-03
- Limitations
- Absence of a located public record does not prove absence of asbestos aboard. Deck logs (RG 24), Defoe contract/work-package records, and French-service records are undigitized leads. Does not establish or defeat any claim of exposure or legal eligibility.
- Atlas source
- true
- Evidence ID
- ev-uss-pc-481-pc481-09