Evidence
10 evidence entries recorded; each entry has a stable permalink (#ev-1 … #ev-10).
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[1]NavSource Online: Submarine Chaser Photo Archive, SC-531 page - designation timeline, specifications, commanding officers (verified live 2026-10-03); corroborated by uboat.net warship entry (build dates, CO list) [other_primary]
- Locator
- NavSource 12/150531.htm header block, specifications block, commanding-officers table
- Finding type
- vessel_history
- Finding
- NavSource timeline for this hull: laid down 27 March 1941 by Westergard Boat Works, Inc., Rockport, TX; launched 4 September 1941; commissioned PC-531, 27 May 1942; reclassified SC-531 in April 1943; visited Auckland, New Zealand 18-27 July 1944; struck from the Naval Register 19 December 1945; transferred to the Maritime Commission 27 February 1948; 'Fate unknown.' Specifications: displacement 148 t.; length 110'10"; beam 17'; draft 6'6"; speed 15.6 kts.; complement 28; armament one 40mm mount, two .50-cal machine guns, two depth-charge projector 'Y guns,' two depth-charge tracks; propulsion two 880-bhp General Motors 8-268A diesel engines, Snow and Knobstedt single-reduction gear, two shafts. Commanding officers tabulated (partial): LTJG Grant H. Wykhuis USNR (1944 - 6 January 1945), LTJG Jerome D. Gainer D-V(S) USNR (20 January 1945), LTJG S. W. Crocker USNR (May 1945), LTJG Joseph S. King D-V(S) USNR (6 September 1945). Page explicitly states 'There is no DANFS history available for SC-531.'
- Verification
- verified
- Role
- context
- Documentation level
- ship_specific
- Accessed
- 2026-10-03
- Study period
- 1941-1948
- Population
- Westergard construction trades (1941-42); crew (1942-45, ~28)
- Limitations
- NavSource is a volunteer secondary compilation, not a primary registry - milestone dates generally track NVR/official sources but should be re-verified against deck logs. The commanding-officer dates conflict internally with the October 1944-October 1945 muster roll and Wykhuis's own memoir (see ev-05, ev-06, and gaps). Contains no asbestos content. Live page verified loading on navsource.net 2026-10-03 (navsource.org is dead).
- Atlas source
- true
- Evidence ID
- ev-uss-sc-531-01
-
[2]DANFS, Gato III (SS-212) - fifth war patrol narrative naming SC-531 (verbatim transcription; live NHHC DANFS page returned 404 on 2026-10-03) [nhhc_danfs]
- Locator
- DANFS Gato III service narrative, fifth war patrol paragraph
- Finding type
- vessel_history
- Finding
- Ship-specific operational record for this hull in the Solomons: on USS Gato's (SS-212) fifth war patrol (19 March - 6 June 1943), 'she landed an Australian Intelligence party at Toep, Bougainville, 29 March 1943, and evacuated 27 children, 9 mothers, and 3 nuns, transferring them 31 March to SC-531 off Ramos, Florida Island.' Documents SC-531 operating in the Florida Islands/Solomons area on 31 March 1943 and performing an evacuee-transfer rendezvous with a fleet submarine.
- Verification
- verified
- Role
- context
- Documentation level
- ship_specific
- Accessed
- 2026-10-03
- Study period
- 1943-03-31
- Population
- SC-531 crew (March 1943); 39 evacuees transferred from USS Gato (27 children, 9 mothers, 3 nuns)
- Limitations
- Names this hull in a single operational event; establishes presence off Ramos Island, Florida Islands, 31 March 1943 - not a continuous service chronology. Transcription of the printed DANFS volume via HyperWar; the live NHHC page for Gato III returns 404 (same link-rot pattern noted in prior batches). No asbestos content.
- Atlas source
- true
- Evidence ID
- ev-uss-sc-531-02
-
[3]USS Maury (DD-401) war diary / operational remarks transcription, 6 August 1943 (Destroyer History Foundation transcription of the ship's deck log) [other_primary]
- Locator
- Maury DD-401 war diary, 6 August 1943 entry, 0800-1200 watch, dispatch recital
- Finding type
- historical_record
- Finding
- Ship-specific operational record for this hull in the Solomons: ComTaskFor 31 secret dispatch 060429 of August 1943 'directed Commander Sims in MAURY with SC 531, LST 395 and one other LST depart Kukum at 1200 love, August 7, to arrive Rendova at 0700 love, August 8. MAURY to make A/S sweep toward Russells and SC 531 to make A/S sweep in Blanche channel, to return to Rendova at 1800 love, August 8, to return with LST's to Koli Point.' Documents SC-531 escorting LSTs Kukum-to-Rendova during the New Georgia campaign and assigned an anti-submarine sweep of Blanche Channel, 7-8 August 1943.
- Verification
- verified
- Role
- context
- Documentation level
- ship_specific
- Accessed
- 2026-10-03
- Study period
- 1943-08-06 to 1943-08-08
- Population
- SC-531 crew (August 1943); USS Maury; LST-395 and one additional LST crews
- Limitations
- Volunteer transcription of a NARA-held deck log (hosted by the Destroyer History Foundation); the underlying document is a contemporaneous government record, but the transcription itself is unofficial - verify against the NARA original for citation-grade use. Establishes ordered employment, not completion of the sweep. No asbestos content.
- Atlas source
- true
- Evidence ID
- ev-uss-sc-531-03
-
[4]ShipbuildingHistory.com (Tim Colton), Westergard Boat Works yard page - yard history and construction table (verified live 2026-10-03) [other_primary]
- Locator
- Westergard Boat Works table, SC 531 row; yard-history narrative
- Finding type
- vessel_history
- Finding
- Builder-yard record for this hull: the Westergard table lists 'SC 531, US Navy, Sub Chaser, 136d tons, Built 27-May-42, To MARAD 1948' - corroborating the commissioning-date/disposal line. Yard history: Westergard Boat Works was formed in 1940 by W. P. Kennedy, Jr. (of the Kennedy Engine Company family) and A. M. Westergard; its home yard sat at the foot of Lee Street on Biloxi's Back Bay, Mississippi (site now razed into Biloxi Point Park); the table notes the SC-497-class hulls SC-497 and SC-498 were 'Built in Rockport TX' - Westergard's wartime Rockport, Texas operation, consistent with NavSource's Rockport builder location for this hull. The yard also built six additional SCs (SC-530, SC-650, SC-651, SC-654, SC-655) plus BYMS-class minesweepers and Army passenger boats.
- Verification
- verified
- Role
- context
- Documentation level
- ship_specific
- Accessed
- 2026-10-03
- Study period
- 1940-1948 (yard coverage)
- Population
- Westergard construction trades, Rockport TX (1941-42)
- Limitations
- Volunteer-compiled yard reconstruction (Colton's shipbuildinghistory project) - the standard public reference for small-yard build lists, but a secondary compilation, not a registry. 'Built 27-May-42' is the commissioning date (hull launched 4 September 1941). No asbestos or materials content; no yard industrial-hygiene record exists for Westergard in located sources.
- Atlas source
- true
- Evidence ID
- ev-uss-sc-531-04
-
[5]SC-531 Subchaser Site (decade.com, archived) - crew tribute site compiled from National Personnel Records Center records, National Archives at College Park records, family records, conversations with SC-531 CO Grant H. Wykhuis, and subchaser researchers incl. Theodore R. Treadwell (live domain dead - archived copy cited) [other_primary]
- Locator
- decade.com SC-531 pages via Wayback: SC-531mustroll.html (20160415210101), SC-531Shipsinlog.html (20160416031049), SC-531portsvisited.html (20160416041408), Enemy Planes Down image (20190224131507im_)
- Finding type
- historical_record
- Finding
- Veterans' record compilation for this hull: (1) October 1944 - October 1945 muster roll - Lt.(jg) Jerome D. Gainer commanding officer 'relieved of command 1/20/45'; Lt.(jg) Joseph S. King 'assumed command 9/6/45'; Lt. Grant H. Wykhuis listed as commanding officer (see conflicts in gaps); (2) ship's log extracts - 4 November 1944 found an LCM adrift and sinking off 'Nauowea' (Nanumea) Atoll and took survivors aboard; 11 November 1944 took 10 enlisted men and 2 officers off sinking LCT-128 and sank the hulk by gunfire (survivor names listed, incl. LCT-128 CO Ens. S. L. Silverman); other ships in log: SC-1045, ATA-214, ATR-28, ATO-134, USS Spangler (DE-696), LCT-133, YMS-117, APC-98, SC-640; (3) ports list - Espiritu Santo (home port October 1944), Funafuti, Nanumea, Nukufetau, Nui (Ellice Islands), Pago Pago, Noumea, Suva/Lautoka/Vuda Point (Fiji), Canton, Palmyra, Pearl Harbor Berth #2 drydocks, Pier 21 Treasure Island San Francisco - with Solomon Islands among island groups visited; (4) a wartime crew photograph shows a painted scoreboard on the vessel bearing two Japanese rising-sun flags (enemy-aircraft kill markings, claim unverified).
- Verification
- partial
- Role
- archival_lead
- Documentation level
- ship_specific
- Accessed
- 2026-10-03
- Study period
- 1944-10 to 1945-10
- Population
- SC-531 crew October 1944 - October 1945 (muster roll names ~40); rescued LCT-128/LCM survivors (November 1944)
- Limitations
- Family/veteran-compiled site: its sources (NPRC, NARA College Park, CO interviews) are primary-class but the transcriptions carry visible typos ('Espirito Santos,' '10/6/1044') and unverified claims - use as an archival lead and corroboration, not as a registry source. The kill-marking photograph is a crew-claim artifact, not a confirmed combat credit. The live domain is dead (re-purposed); all citations are Wayback captures. No asbestos content.
- Atlas source
- true
- Evidence ID
- ev-uss-sc-531-05
-
[6]Grant H. Wykhuis, 'WORLD WAR II' - first-person memoir, 'Commander United States Subchasers SC-531 and SC-638' (23 February 2003; archived copy - live domain dead) [other_primary]
- Locator
- Wykhuis memoir chapters 9-12 (SC-531, Pago Pago, Noumea, Pearl Harbor and Home)
- Finding type
- historical_record
- Finding
- Commanding-officer memoir for this hull's 1945 service: Wykhuis (a Wisconsin forester drafted 1941, commissioned via V-7 training May 1942) previously commanded SC-638 in the Mediterranean (Salerno, Anzio, Vis, southern France; SC-638 transferred to France), departed San Francisco by transport 19 December 1944, flew Pearl Harbor to Espiritu Santo by PBY, and took command of 'USS 531' there on harbor-entrance patrol - relieving the prior skipper in early January 1945 (muster: Gainer relieved of command 1/20/45). Under Wykhuis: ~1 month Espiritu Santo patrol/supply-depot refit; ordered to Pago Pago, American Samoa (~6 weeks training patrol); ordered to Noumea, New Caledonia (storm transit via Suva; drydock to check shafts and screws); ordered to Pearl Harbor with a second SC ('Smithy's ship,' which suffered a shaft casualty and was towed in by a Pearl Harbor tug) via Espiritu Santo, Funafuti, Canton, Palmyra - learning of Hiroshima at Espiritu Santo 6 August 1945. At Pearl he turned the ship over to 'Steve' (the second officer - consistent with Lt.(jg) Joseph S. King's muster-roll assumption of command 9/6/45) and left for Destroyer Escort school.
- Verification
- partial
- Role
- context
- Documentation level
- ship_specific
- Accessed
- 2026-10-03
- Study period
- 1945-01 to 1945-09
- Population
- SC-531 crew under Wykhuis, January-September 1945
- Limitations
- Informal memoir written ~58 years after events (2003, self-published on the family crew site): a primary-witness account but not an official record; dates are approximate ('about six weeks,' 'a period of about a month'). The 'Steve' identification with Joseph S. King is inference - unverified. Contains no asbestos or materials content beyond noting the vessel's worn material condition on his arrival (non-functioning crew toilets, broken fittings).
- Atlas source
- true
- Evidence ID
- ev-uss-sc-531-06
-
[7]Era/class design basis: NavSource SC-531 specifications (wooden SC-497-class hull, 2 x GM 8-268A diesels) + Splinterfleet.org (Theodore R. Treadwell, author of 'Splinter Fleet: The Wooden Subchasers of World War II') - class history and construction program [other_primary]
- Locator
- NavSource spec block (propulsion, wooden-hull class designation); splinterfleet.org class-history narrative (438 boats, ~50 yards, complement 3+24)
- Finding type
- asbestos_application
- Finding
- A 110-foot wooden-hull, diesel-powered submarine chaser built 1941-42 in a small Gulf Coast boatyard carries a fundamentally different asbestos-relevant profile than a steel steam vessel: no boilers, no steam plant, no turbine or steam-line lagging. The SC-497 class was designed for mass production by small wooden-boat yards (438 launched and commissioned across ~50 yards per Treadwell) using wood construction, diesel machinery, and minimal compartmentation. Era-standard applications aboard a 1942 diesel patrol craft of this type were diesel exhaust lagging/insulation in the engine space, gaskets and valve/stem packing, and electrical insulation/fireproofing - plausible era-consistent materials, several of which were commonly asbestos-containing in 1942.
- Verification
- inferred
- Role
- supporting
- Documentation level
- class_or_era
- Accessed
- 2026-10-03
- Study period
- 1941-1948
- Population
- Westergard construction trades (1941-42); crew (1942-45); any post-Navy owners (1948+)
- Limitations
- Class/era inference only - no hull-specific insulation survey, material list, or work package located for SC-531; names era-standard applications, not confirmed installed materials. Wooden SC hulls carried materially less insulation than steel steamships; whether ANY asbestos was aboard this hull is unverified. No manufacturer attribution. Does not establish quantity, individual exposure, or present-day presence.
- Atlas source
- true
- Evidence ID
- ev-uss-sc-531-07
-
[8]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 entire construction (1941-42) and service era (1942-45).
- 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. The GAO review centered on Navy shipyard worker protection aboard larger vessels - its bearing on a 110-foot wooden diesel chaser is indirect. Full text not retrieved (gao.gov returned HTTP 403 to automated fetch, confirmed 2026-10-03) - content via product-page description.
- Atlas source
- true
- Evidence ID
- ev-uss-sc-531-08
-
[9]Batch-7906 search ledger (this record): NavSource SC-531; DANFS Gato III (HyperWar transcription); USS Maury DD-401 war diary; shipbuildinghistory.com Westergard; decade.com SC-531 veterans' site (Wayback); Wykhuis memoir; splinterfleet.org; uboat.net; MARAD Vessel History Database; NARA catalog; GAO product page; CourtListener (4 base queries run - all hits name collisions); secondary web litigation sweep [other_primary]
- Locator
- search_ledger rows sl-uss-sc-531-01 through -14
- Finding type
- historical_record
- Finding
- No qualifying ship-specific asbestos record located: no asbestos survey, abatement contract, hazmat disclosure, or verified litigation naming SC-531 (or its brief PC-531 designation) was found in the public sources searched. No DANFS entry exists for this hull (NavSource states so explicitly). The only 'asbestos aboard' material found in web sweeps is law-firm marketing listicles naming SC-class subchasers generically - excluded by source policy.
- 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. CourtListener litigation sweep completed 2026-10-03: four base queries returned hits that were all name collisions (Kentucky Supreme Court 'SC-...-531' docket citations, Alabama/Georgia reporter cites, fuzzy docket-text matches) - a real negative result for vessel-named litigation, not a blocked search. NARA deck logs (RG 24) for this hull are undigitized - the muster/log extracts on the veterans' site show such records exist. Does not establish or defeat any claim of exposure or legal eligibility.
- Atlas source
- true
- Evidence ID
- ev-uss-sc-531-09
-
[10]Designation cross-check: NavSource SC-531 page ('ex-PC-531'; commissioned PC-531 27 May 1942; reclassified SC-531 April 1943) + NavSource SC/PC index (SC-497-class entries marked 'ex-PC-xxx'; PC-461 class listed separately as 173' steel) + Norwegian museum-vessel record (HNoMS Hitra = ex-SC-718, Fisher Boat Works, Detroit - Wikipedia/museumships.us) [other_primary]
- Locator
- NavSource SC-531 header ('ex-PC-531') and timeline; NavSource 12/01idx.htm class index; HNoMS Hitra museum/secondary record (ex-SC-718)
- Finding type
- historical_record
- Finding
- CORRECTION/DISAMBIGUATION: (1) This hull carried a transient 'PC-531' designation at commissioning (27 May 1942) and was reclassified SC-531 in April 1943 - a paper designation on an SC-497-type wooden hull, like lead sister SC-497 itself ('ex-PC-497'). She was never a PC-461-class 173-foot steel patrol craft - the PC-461-class numbering scheme does not include a steel PC-531 (the 5xx block was assigned to wooden SC-type hulls ordered under PC designations and reclassified to SC). A 'USS PC-531' never existed as a distinct vessel. (2) A Wikipedia SC-497-class template row can be misread to suggest SC-531 became Norway's HNoMS Hitra - false: Hitra is ex-SC-718, built by Fisher Boat Works, Detroit, and is the preserved museum vessel. SC-531 went to the Maritime Commission in 1948; fate unknown.
- Verification
- partial
- Role
- correction
- Documentation level
- ship_specific
- Accessed
- 2026-10-03
- Study period
- 1942-1943 (designation window)
- Limitations
- Corrects designation confusion and a secondary-index conflation, not a material claim. The reclassification date ('April 1943') and the commissioning designation rest on NavSource's secondary compilation - consistent with the class-wide PC->SC renumbering but not re-verified against a BuShips directive. No asbestos content.
- Atlas source
- true
- Evidence ID
- ev-uss-sc-531-10