Evidence
15 evidence entries recorded; each entry has a stable permalink (#ev-1 … #ev-15).
-
[1]research packet 1006-packet.md [other_primary]
- Finding type
- vessel_history
- Finding
- Identity packet verdict: MISMATCH (RE-SCOPE).
- Verification
- verified
- Role
- correction
- Documentation level
- ship_specific
- Evidence ID
- uss-thi-tu-pgm73-pkt-1006-packet-md
-
[2]NavSource Online: Motor Gunboat/Patrol Gunboat Photo Archive, PGM-73 (live page verified 2026-10-04) [museum_official]
- Locator
- PGM-73 page: construction/transfer block, Specifications block, 'no DANFS history' note
- Finding type
- vessel_history
- Finding
- Documented for this hull: 'PGM-73 was built for South Vietnam.' PGM-71 class motor gunboat laid down as PGM-73 by Peterson Builders, Sturgeon Bay, WI; launched 9 November 1964; delivered 16 July 1965, transferred under the Military Assistance Program to South Vietnam and named RVN Thi Tu (HQ 613); fate unknown. Specifications: displacement 130 t.; length 101'; beam 22'; draft 6'8"; speed 18 kts.; armament one 40mm mount, two twin 20mm mounts and two .50 cal. machine guns; propulsion 'Two 975bhp MB820 Mercedes Benz diesel engines/eight 250bhp General Motors 6-71 diesel engines, two shafts.' No photograph is archived for this hull. 'There is no DANFS history available for PGM-73.'
- Verification
- verified
- Role
- context
- Documentation level
- ship_specific
- Accessed
- 2026-10-04
- Study period
- 1964-1965
- Population
- Peterson Builders construction workforce (1964-65); RVN operating crew (~1965/66-1975)
- Limitations
- Volunteer-compiled archival record documents identity, construction, delivery, and class specifications - not RVN service detail, post-1975 disposition, materials content, or asbestos. The propulsion line carries two alternative class engine fits (2x Mercedes-Benz MB820 or 8x GM 6-71); the actual fit of this hull is not resolved. Delivery date (16 July 1965) conflicts with the builder-yard table (11 September 1965) - see gaps.
- Atlas source
- true
- Evidence ID
- ev-uss-thi-tu-pgm73-01
-
[3]NavSource Online: Motor Gunboat (PGM) Index - PGM-71 class span and disposition rows (live page verified 2026-10-04) [museum_official]
- Locator
- PGM index page: 'PGM-71 Class Motor Gunboat PGM-71 to PGM-83' header and disposition rows
- Finding type
- vessel_history
- Finding
- The NavSource PGM index delimits the PGM-71 class as PGM-71 to PGM-83 and lists this hull's disposition row: 'PGM-73 to South Vietnam as Thi Tu (HQ 613).' Sister rows show the class distribution: PGM-71 and PGM-79 to Thailand (T-11, T-12); PGM-72 to South Vietnam (Thai Binh HQ 612); PGM-74 (Song Tu HQ 614), PGM-80/-81/-82/-83 to South Vietnam (HQ 615-618); PGM-75/-76 Ecuador (LC 71/72); PGM-77 Dominican Republic (GC 102); PGM-78 Peru (PC 11). The index also notes that all Motor Gunboats hull-numbered 84 and greater in the U.S. Navy inventory on 1 April 1967 were redesignated Patrol Gunboats (PG) - 'the term Motor Gunboat now applies primarily to craft built for allied navies.'
- Verification
- verified
- Role
- context
- Documentation level
- ship_specific
- Accessed
- 2026-10-04
- Study period
- 1963-1967 (class build window)
- Limitations
- Index-level documentation; establishes class span and the MAP-transfer structure, not hull-specific service detail or materials. Class label is NavSource's convention - navypedia groups the same hulls with the wider 'PGM59/71' MAP series; see ship_class field.
- Atlas source
- true
- Evidence ID
- ev-uss-thi-tu-pgm73-02
-
[4]Shipbuilding History, Peterson Builders yard table (live page verified 2026-10-04); corroborated by the same site's 'Gunboats (PGM, PG, PFMM, PCG, PGG) Built Since WWII' table [other_primary]
- Locator
- peterson.htm '30 Motor Gunboats (PGM)' section, PGM 73 row; smallships/pg3.htm PGM-73 row
- Finding type
- vessel_history
- Finding
- The Peterson Builders yard table records: PGM 73 | 'Thi Tu (HQ ...)' | Vietnam | Patrol Gunboat | 130d | 100 ft | delivery 11-Sep-65 - in the '30 Motor Gunboats (PGM)' section spanning PGM-71 through PGM-122, all built by Peterson at Sturgeon Bay for foreign transfer. The companion gunboat table independently lists: 'PGM 73 | Thi Tu | Vietnamese Navy | Peterson | Sturgeon Bay WI | 118 LDT | 100 ft | built 11-Sep-65 | HQ 613, disposition unknown.' The yard page documents Peterson Builders as a Sturgeon Bay, Wisconsin yard (reorganized 1946; closed 1998) specializing in small naval vessels including surface combatants and mine-warfare craft.
- Verification
- verified
- Role
- context
- Documentation level
- ship_specific
- Accessed
- 2026-10-04
- Study period
- 1964-1965
- Population
- Peterson Builders construction workforce (1964-65)
- Limitations
- Private compilation (Tim Colton's Shipbuilding History), not an official registry; its PGM-73 date (11-Sep-65) conflicts with NavSource's 16 July 1965 delivery - unresolved, see gaps. 'Disposition unknown' reflects the compiler's knowledge cutoff, not a finding that disposition is unknowable. No asbestos or materials content.
- Atlas source
- true
- Evidence ID
- ev-uss-thi-tu-pgm73-03
-
[5]Navypedia, 'PHU DU large patrol craft (1963-1967)' - South Vietnam coastal forces table (live page verified 2026-10-04) [other_primary]
- Locator
- svi_cf_phu_du.htm ships table, Thi Tu (HQ613) row; specs block; project-history note
- Finding type
- vessel_history
- Finding
- Navypedia's South Vietnam table lists: Thi Tu | HQ613 | Peterson Builders, Sturgeon Bay, USA | launched 9.11.1964 | completed 7.1965 | fate 'captured by North Vietnam 4.1975.' Class specs given: 30.8 m length, 6.5 m beam, 2.3 m draught, 2 shafts, 2x Mercedes-Benz MB820 or 8x General Motors 6-71 diesels (1950 or 2000 hp), 18 kts, 1x40mm Mk 3 + (1-2)x2 20mm Mk 24, Raytheon 1500 radar, complement 30. Project history: 'Welded steel patrol boats built in USA specifically for foreign transfer. PGM59/71 class. Enlarged variant of USCG 95ft cutter with commercial-type machinery and electronics.'
- Verification
- partial
- Role
- context
- Documentation level
- ship_specific
- Accessed
- 2026-10-04
- Study period
- 1964-1975
- Population
- RVN operating crew (~1965/66-1975); VPN operating crew post-capture
- Limitations
- Secondary naval-reference compilation; the April 1975 capture is asserted at the individual-hull level here but rests on secondary sourcing - no capture document or Vietnamese record was located. Complement figure (30) conflicts with the official NHC study (15) - see gaps. No asbestos or materials content.
- Atlas source
- true
- Evidence ID
- ev-uss-thi-tu-pgm73-04
-
[6]Navypedia, 'PGM59 patrol boats (1963-1966/1975)' - Vietnam People's Navy table (live page verified 2026-10-04) [other_primary]
- Locator
- vie_cf_pgm59.htm ships table, (ex-Thi Tu) row; project-history and naval-service notes
- Finding type
- vessel_history
- Finding
- Navypedia's Vietnam People's Navy table carries the captured boats as a group: '(ex-Thi Tu) | HQ.. | Peterson Builders, Sturgeon Bay | launched 9.11.1964 | 7.1965 // 4.1975 | deleted 1992-95?' The page project history states 'Boats were captured by Vietnam People's army and incorporated into People's navy,' and the naval-service note expressly cautions: 'The fate of individual boats is unknown. Data on the fate of individual boats in the table reflect only the number of units.'
- Verification
- partial
- Role
- context
- Documentation level
- ship_specific
- Accessed
- 2026-10-04
- Study period
- 1975-1995
- Population
- VPN operating crew post-1975 (unquantified)
- Limitations
- The 'deleted 1992-95?' figure is a class-level aggregate estimate - navypedia itself disclaims hull-level fate data, and this hull's post-capture pennant is unknown ('HQ..'). VPN incorporation is therefore a class-level inference applied to this hull, not a hull-documented service record. No asbestos or materials content.
- Atlas source
- true
- Evidence ID
- ev-uss-thi-tu-pgm73-05
-
[7]Diep My Linh, 'Hai-Quan Viet-Nam Cong-Hoa Ra Khoi, 1975' (published RVN fleet history; ISBN 0-9628124-0-4, LoC 90-093493; full-text HTML mirror live-verified 2026-10-04; appendix also at vnnavydallas.com/tailieu/Diep_My_Linh_appendix.pdf) [other_primary]
- Locator
- Chuong I 1966 chronology ('4 PGM: HQ 612, HQ 613, HQ 614 va HQ 615'); appendix 'Tuan-Duyen-Ham (PGM)' table, HQ 613 row; Chapter on the April 1975 exodus (HQ 615 scuttling passage)
- Finding type
- vessel_history
- Finding
- The published RVN fleet history documents receipt timing and the pennant-name pair: under its 1966 chronology, 'Hai-Luc tiep nhan: ... 4 PGM: HQ 612, HQ 613, HQ 614 va HQ 615' (the sea force received HQ 612-615); the appendix fleet list carries 'HQ 613 - Thi-Tu' under 'Tuan-Duyen-Ham (PGM - Patrol Motor Gunboat).' The book's April-May 1975 exodus narrative names the PGM that attempted escape (sister HQ 615 Tay Sa, scuttled after rescue off Vung Tau) but never names HQ 613 among the ships that reached sea - consistent with, though not proof of, the reported April 1975 capture.
- Verification
- partial
- Role
- context
- Documentation level
- ship_specific
- Accessed
- 2026-10-04
- Study period
- 1966-1975
- Population
- RVN operating crew (1966-1975)
- Limitations
- Diaspora-published fleet history (author-compiled, veteran-sourced), not an official registry; receipt-year chronology (1966) reflects RVN in-service entry and reconciles with, but does not exactly match, U.S.-side delivery dates (Jul/Sep 1965). Absence of HQ 613 from the exodus narrative is negative evidence, not a documented capture record. No asbestos or materials content.
- Atlas source
- true
- Evidence ID
- ev-uss-thi-tu-pgm73-06
-
[8]Judith C. Erdheim, 'Market Time' (Department of the Navy, Naval Historical Center, September 1975; prepared for the Office of Naval Research / CNO) - HyperWar transcription, live page verified 2026-10-04 [other_primary]
- Locator
- market_time.htm: 'Pre-Market Time Vietnamese Coastal Surveillance' section; 'Cloud concept' passage; Appendix A FIG A-2
- Finding type
- historical_record
- Finding
- The official U.S. Naval Historical Center study documents the VNN PGM's operating context: pre-1965 blockade patrol units 'consisted of one to three PCEs ... four PGMs (102 foot patrol motor gunboats), an LSIL ..., and an oiler and light cargo ship'; under the later 'Cloud' inner-barrier concept 'a typical task unit consisted of one PGM and 4 PCFs/WPBs'; and the type's known limitation - 'the PGM did not prove to have the necessary shallow-water capability.' Appendix A FIG A-2 gives VNN PGM characteristics: 100 ft, 21 ft beam, 7 ft draft, 17 kts, endurance 1,000 n.mi. at 12 kts, crew 1 officer + 14 enlisted, armament 1-40mm single-mount Mk 3, 2-.50 cal, 2-20mm single-mount Mk 10 Mod 2.
- Verification
- verified
- Role
- context
- Documentation level
- class_or_era
- Accessed
- 2026-10-04
- Study period
- 1963-1975
- Population
- VNN PGM crews class-wide (1963-1975)
- Limitations
- Type-level official history; documents the class's role and characteristics, not this hull's individual operations or materials. Crew figure (15) conflicts with navypedia (30) and the Vietnamese fleet table (2+25) - carried as an unresolved variance. No asbestos content.
- Atlas source
- true
- Evidence ID
- ev-uss-thi-tu-pgm73-07
-
[9]NIOSH Walk-through survey report, Peterson Builders, Inc., Sturgeon Bay, Wisconsin (Levine & Schott; survey 15 Dec 1978; report Nov 1979, IWS 74-48; CDC Stacks record live-verified 2026-10-04) [other_primary]
- Locator
- CDC Stacks record cdc:233468 (abstract); PDF cdc_233468_DS1.pdf
- Finding type
- gov_survey
- Finding
- Government documentation of this hull's builder yard: a NIOSH industrial-hygiene walk-through evaluated Peterson Builders (SIC-3731 ship building and repairing) for health and safety hazards of paint materials. Approximately 731 employees worked in the boat production yard; the company had no industrial hygiene program; indoor paint spraying with poor ventilation and respirator use documented. The authors concluded Peterson would be an excellent facility for further study given the large volume of paint used and steady workload.
- Verification
- verified
- Role
- context
- Documentation level
- class_or_era
- Accessed
- 2026-10-04
- Study period
- 1978-1979 (survey/report); construction-era relevance only
- Population
- Peterson Builders workforce (~731 employees, 1978)
- Limitations
- Yard-level survey, not a hull record - and it is a PAINT-materials hazard evaluation: it contains NO asbestos evaluation, exposure measurement, or material inventory. It postdates this hull's construction by ~14 years (yard still active, workforce documented at 731). Does not establish asbestos presence, use, or exposure for this hull or this yard.
- Atlas source
- true
- Evidence ID
- ev-uss-thi-tu-pgm73-08
-
[10]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 - postdating this hull's 1964-65 construction.
- Verification
- verified
- Role
- context
- Documentation level
- class_or_era
- Accessed
- 2026-10-04
- Study period
- 1979
- Population
- Navy shipyard workers; asbestos program review
- Limitations
- Program-level documentation of U.S. Navy shipbuilding practice; supports era context only, not any fact specific to this hull. Caveat particular to this record: the hull was a MAP export built to a U.S. design at a commercial Wisconsin yard - Navy-spec materials practice is a reasonable but unverified inference for export-fit construction. Full text not retrieved (gao.gov blocks automated fetch, HTTP 403, confirmed 2026-10-04) - content via product-page description.
- Atlas source
- true
- Evidence ID
- ev-uss-thi-tu-pgm73-09
-
[11]EPA CERCLA site profile, PETERSON BUILDERS INC, 107 East Walnut Street, Sturgeon Bay, WI (EPA ID WID096828975, Region 05; live page verified 2026-10-04) [other_primary]
- Locator
- EPA CERCLA site-information page, site ID 0507082
- Finding type
- environmental_record
- Finding
- EPA Superfund profile exists for the builder yard site: 'Not on the NPL', non-NPL status 'Deferred to RCRA (Subtitle C)' - i.e., the former Peterson Builders site at 107 East Walnut Street, Sturgeon Bay, had its environmental management handled under hazardous-waste (RCRA) rather than Superfund authorities.
- Verification
- verified
- Role
- archival_lead
- Documentation level
- class_or_era
- Accessed
- 2026-10-04
- Study period
- site file undated; construction relevance only
- Limitations
- Archival lead only: the profile establishes that the builder yard has a federal hazardous-waste/environmental file; it contains no asbestos-specific content and nothing about this hull. Any RCRA case file for the site (Wisconsin DNR / EPA Region 5) is the next repository for yard-level material or demolition records.
- Atlas source
- true
- Evidence ID
- ev-uss-thi-tu-pgm73-10
-
[12]Era inference built on: NavSource/shipbuildinghistory/navypedia construction data (130-ton diesel PGM, built 1964-65, Peterson Builders); NavSource and navypedia propulsion lines (2x MB820 Mercedes-Benz or 8x GM 6-71 diesels, 2 shafts - no steam plant); GAO HRD-80-2 era documentation (ev-09) [other_primary]
- Locator
- ev-01, ev-03, ev-04 spec data; ev-09 era documentation
- Finding type
- asbestos_application
- Finding
- A 130-ton diesel motor gunboat built 1964-65 at a U.S. commercial yard to a U.S. Navy MAP design precedes the early-1970s asbestos-substitution era; era-consistent candidate materials aboard a small diesel patrol craft of this period are engine/exhaust lagging, gaskets, valve packing, electrical insulation, and interior deck/surface coverings. The plausible material set is materially narrower than for steam vessels - no boiler or turbine lagging pathway exists; small truck-derived diesels in an austere ~100-ft hull present limited lagging volume.
- Verification
- inferred
- Role
- supporting
- Documentation level
- class_or_era
- Accessed
- 2026-10-04
- Study period
- 1964-1975+
- Population
- Peterson Builders construction trades (1964-65); RVN crew (~1966-75); VPN crew post-1975
- Limitations
- Class/era inference only - no hull-specific material list, insulation survey, or work package located for PGM-73. Names era-candidate applications, not confirmed installed materials; no quantity; no manufacturer attribution. Export-fit (MAP austere variant) may have differed from USN fits - materials practice on FMS export hulls is not documented here.
- Atlas source
- true
- Evidence ID
- ev-uss-thi-tu-pgm73-11
-
[13]Mai Thanh Hai & Tuong Linh, 'Nhung con tau giu dao: Huyen thoai HQ-613' (Viet Giai Tri news feature, 14 Mar 2025; live page verified 2026-10-04) - documenting the Vietnam People's Navy's HQ-613 at the Spratly (Truong Sa) deployments of 1987-88 [reputable_press]
- Locator
- vietgiaitri.com feature: Cao Duc Tai interview passage ('Tau HQ-613 dua vao bien che cua Lu doan 125 hai quan tu nam 1967. Tau co luong gian nuoc 590 tan...')
- Finding type
- historical_record
- Finding
- CORRECTION - pennant-number collision: a different hull carried 'HQ-613' in Vietnam People's Navy service. The veteran-sourced feature describes VPN HQ-613 as a ~590-ton transport on the rolls of Naval Brigade 125 since 1967, crew 22, configured to carry ~100 m3 of water and 80 tons of fuel, armed with 2x 12.7mm AA guns - a vessel that cannot be the 130-ton ex-PGM-73 (which moreover remained in RVN hands until April 1975). Low-quality aggregator pages (e.g., a violet.vn school-blog entry) nonetheless identify the Spratly veteran HQ-613 as 'tien than la PGM-73 cua My' (formerly the U.S. PGM-73) - a conflation of the shared pennant number with the hull. The documented VPN HQ-613's 1967 in-service date alone precludes identity with ex-PGM-73.
- Verification
- partial
- Role
- correction
- Documentation level
- ship_specific
- Accessed
- 2026-10-04
- Study period
- 1967-1988 (the OTHER HQ-613's documented service window)
- Limitations
- Corrects a circulating identity error, not a materials claim. The reliable half of the collision (590-ton Brigade 125 ship since 1967) is a veteran-interview press feature - reputable but not an official registry; the conflating source is a school-blog aggregator of unknown provenance. What ex-PGM-73 was actually numbered or employed as after capture remains undocumented (navypedia: individual fates unknown).
- Atlas source
- true
- Evidence ID
- ev-uss-thi-tu-pgm73-12
-
[14]Archival leads: NHHC Operational Archives, Naval Advisory Group Vietnam collection COLL-353 (265 boxes, 88 cu ft, 1954-1974, Saigon headquarters records); COMNAVFORV Monthly Historical Summaries (digitized series incl. VNN statistical summaries); Military Assistance Program transfer case files; Vietnam People's Navy service records [other_primary]
- Locator
- NHHC Operational Archives COLL-353 finding aid (URL returned 404 on fetch; metadata via search index); COMNAVFORV monthly-summaries archive path
- Finding type
- historical_record
- Finding
- Hull-level records for an advisory-era MAP transfer plausibly sit in U.S. advisory channels rather than ship registers: the NHHC Operational Archives' Naval Advisory Group Vietnam collection (COLL-353, 265 boxes covering 1954-1974) holds the Saigon-headquarters records from which MAP deliveries and VNN material condition reporting would have flowed; the COMNAVFORV Monthly Historical Summary series carried recurring VNN statistical summaries. VPN-side service records for the post-1975 period were not located in public form.
- Verification
- partial
- Role
- archival_lead
- Documentation level
- class_or_era
- Accessed
- 2026-10-04
- Study period
- 1954-1974 (collection coverage)
- Limitations
- Archival lead only - establishes repository locations, not contents; no box/folder was pulled and nothing in these collections is shown to mention PGM-73 or HQ-613. Access gap: the NHHC finding-aid PDF (history.navy.mil .../naval-advisory-group-vietnam-coll-353.pdf) and the COMNAVFORV monthly-summary PDFs returned HTTP 404 on 2026-10-04 (standing NHHC link-rot defect; collection metadata via search-index capture).
- Atlas source
- true
- Evidence ID
- ev-uss-thi-tu-pgm73-13
-
[15]Batch-8630 search ledger (this record): NavSource PGM-73 page and PGM index; shipbuildinghistory pg3 + Peterson yard tables; navypedia SVN/VPN pages; Diep My Linh RVN fleet history; NHC Market Time; NIOSH/CDC Stacks; EPA CERCLA; GAO product page; CourtListener authenticated API v4; secondary web sweeps [other_primary]
- Locator
- search_ledger rows sl-uss-thi-tu-pgm73-01 through -14
- Finding type
- historical_record
- Finding
- No qualifying ship-specific asbestos record located: no asbestos survey, abatement contract, hazmat disclosure, materials list, or verified litigation naming PGM-73 / RVNS Thi Tu (HQ-613) was found in the public sources searched. CourtListener exact-name opinion query 'Thi Tu' (authenticated, limit 20) returned a 6,987-count result set composed of unrelated Vietnamese personal-name collisions - no vessel case surfaced; exact-name docket 'Thi Tu', hull-number opinion/docket 'PGM-73', and the protocol-eligible asbestos-qualified variant 'Thi Tu' asbestos were each submitted to the authenticated fleet helper multiple times and pacing-blocked before results returned on every attempt (open gap, not a negative result). Secondary web sweeps surfaced no qualifying case.
- Verification
- verified
- Role
- negative_finding
- Documentation level
- ship_specific
- Accessed
- 2026-10-04
- Study period
- 2026-10-04
- Limitations
- Absence of a located public record does not prove absence of asbestos aboard - and the litigation sweep is incomplete: three of four required base queries were pacing-blocked (fleet-wide hourly budget), so the litigation status of this hull is genuinely open, not negative. Deck logs, MAP transfer case files, NAG subject files (COLL-353), RVN and VPN service records are undigitized leads. Does not establish or defeat any claim of exposure or legal eligibility.
- Atlas source
- true
- Evidence ID
- ev-uss-thi-tu-pgm73-14