Evidence
13 evidence entries recorded; each entry has a stable permalink (#ev-1 … #ev-13).
-
[1]research packet 968-packet.md [other_primary]
- Finding type
- vessel_history
- Finding
- Identity packet verdict: **VERIFIED
- Verification
- verified
- Role
- supporting
- Documentation level
- ship_specific
- Evidence ID
- uss-yms-473-pkt-968-packet-md
-
[2]NavSource Online: Mine Warfare Vessel Photo Archive, YMS-473 (ex-PCS-1443) - construction timeline, reclassification, specifications, disposition (verified live) [other_primary]
- Locator
- NavSource 11/19473.htm header timeline block and Specifications block
- Finding type
- vessel_history
- Finding
- Documented for this hull: 'Laid down 10 May 1943 as a Patrol Craft Sweeper, PCS-1443 by the Harbor Boatbuilding Co., Terminal Island, CA. Reclassified as an Auxiliary Motor Minesweeper, YMS-473, 27 September 1943. Launched 22 April 1944. Completed 22 August 1944. Struck from the Naval Register 19 June 1946. Transferred to the State Department, Foreign Liquidation Commission; sold to South Korea 24 July 1947 and named Gowon (YMS 517).' Specifications: displacement 270 t.; length 136'; beam 24'6"; draft 8'; speed 15 kts.; complement 32; armament one 3"/50 dual-purpose mount, two 20 mm mounts, two depth-charge projectors; propulsion two 880 bhp General Motors 8-268A diesel engines, Snow and Knobstedt single reduction gear, two shafts. Page states 'There is no DANFS history currently available for YMS-473.'
- Verification
- verified
- Role
- context
- Documentation level
- ship_specific
- Accessed
- 2026-10-04
- Study period
- 1943-1948
- Population
- Harbor Boatbuilding construction trades (1943-44); U.S. Navy crew (1944-46); Korean Coast Guard/ROKN crew (1947-48); North Korean crew (1948-)
- Limitations
- NavSource is a volunteer secondary compilation tracking the Naval Vessel Register and Navy registers, not a primary registry. 'Sunk in 1948' on this page is corrected by Korean records (see ev-07/ev-08): the loss was by mutiny/defection to North Korea, not sinking. Contains no asbestos content. PCS-1443 designation was pre-launch only - she never served under it.
- Atlas source
- true
- Evidence ID
- ev-uss-yms-473-01
-
[3]uboat.net Allied Warships of WWII, USS YMS-473 (YMS-473) - order and milestone record (verified live) [other_primary]
- Locator
- uboat.net ship/9890 data table
- Finding type
- vessel_history
- Finding
- Ship data page for this hull: ordered 16 November 1942; built by Harbor Boat Building Co. (Terminal Island, California); laid down 10 May 1943; launched 22 April 1944; commissioned 22 August 1944; stricken 19 June 1946; 'Sold to Korea on 24 July 1947'; former name PCS-1443. No commanding officers are listed for this vessel.
- Verification
- verified
- Role
- context
- Documentation level
- ship_specific
- Accessed
- 2026-10-04
- Study period
- 1942-1947
- Population
- Construction trades; U.S. Navy crew
- Limitations
- Secondary database (Guðmundur Helgason's Allied Warships register) - consistent with NavSource on all shared dates. 'Commissioned 22 Aug 1944' vs NavSource 'Completed 22 Aug 1944' - same milestone, different label; carried as commissioned/completed 1944-08-22. Contains no asbestos content.
- Atlas source
- true
- Evidence ID
- ev-uss-yms-473-02
-
[4]ShipbuildingHistory (Colton) 'Yard Minesweepers YMS BYMS' type ledger and Harbor Boatbuilding yard ledger (navalmarinearchive.com/sbh mirror) - construction record for yard hull 183 [other_primary]
- Locator
- shipbuildinghistory.com/smallships/ym.htm row 'YMS 473'; navalmarinearchive.com/sbh/shipyards/small/harbor.html row 183
- Finding type
- vessel_history
- Finding
- Two construction-register entries for this hull: (1) type ledger - 'YMS 473 | Harbor Boatbuilding | Terminal Island CA | 136 | 320 | 22-Aug-44 | To South Korea 1948 as Ko Won, sunk 1948'; (2) Harbor Boatbuilding yard ledger - hull no. 183, 'PCS 1443/YMS 473', US Navy, Sub Chaser, 245d/136, delivered 22-Aug-44, same disposition line. Confirms builder, hull number pairing (PCS-1443 = YMS-473), and delivery/completion date 22 August 1944.
- Verification
- verified
- Role
- context
- Documentation level
- ship_specific
- Accessed
- 2026-10-04
- Study period
- 1943-1948
- Population
- Harbor Boatbuilding construction trades
- Limitations
- Secondary compilation (Tim Colton's shipbuilding record, the standard U.S. small-ship construction register) - milestone data consistent with NavSource/uboat.net. 'Sunk 1948' is corrected by Korean records (defection, not sinking - ev-07/ev-08). The same type ledger separately lists BYMS-18 'To South Korea as YMS-517, scrapped' - a pennant conflation documented in ev-08; the BYMS-18 hull is ROKN Gyeongsan (YMS-515) elsewhere. Displacement shown as 320 t. vs NavSource 270 t. - spec conflict carried in gaps. Contains no asbestos content.
- Atlas source
- true
- Evidence ID
- ev-uss-yms-473-03
-
[5]NARA, file unit 'YMS-473, 8/23/44-4/1/46' (NAID 193180722), Record Group 24 (Records of the Bureau of Naval Personnel - deck logs and muster rolls), 80 images, digitized via NARA-Ancestry partnership; page image 32863_255947-00060 sampled directly [other_primary]
- Locator
- catalog.archives.gov/id/193180722; sampled image 32863_255947-00060 (quarterly muster roll, 31 Dec 1945, forwarded from Sasebo 4 Jan 1946)
- Finding type
- historical_record
- Finding
- Primary ship documentation exists and is digitized for this hull's entire U.S. Navy career (the day after commissioning through 1 April 1946). The catalog title dates the file 8/23/44-4/1/46, consistent with commissioning 22 August 1944. A directly sampled page (image 60) is the ship's quarterly muster roll dated 31 December 1945, forwarded 4 January 1946 'From Sasebo, Kyushu, Japan,' signed by the executive officer and approved by commanding officer Lt.(jg) J. W. Graves, USNR - primary evidence placing this hull and her named command at Sasebo during the post-surrender occupation minesweeping window.
- Verification
- verified
- Role
- supporting
- Documentation level
- ship_specific
- Accessed
- 2026-10-04
- Study period
- 1944-1946 (file coverage); page sampled December 1945-January 1946
- Population
- U.S. Navy crew of YMS-473 (1944-46); named in sampled page: CO Lt.(jg) J. W. Graves, USNR
- Limitations
- Muster-roll/deck-log file = personnel and movement records; contains no asbestos or material-content information. Only one content page (of 80) was sampled; the roll establishes presence and command, not the nature of operations performed or materials aboard. Catalog is partially JS-rendered; NAID, coverage dates, image count and RG verified directly.
- Atlas source
- true
- Evidence ID
- ev-uss-yms-473-04
-
[6]Navy and Marine Corps Awards Manual NAVPERS-15790 (Rev. 1953), ship-participation list for WWII area campaign medals - YMS-473 entry (verbatim mirror at officialmilitaryribbons.com; manual itself at HyperWar ibiblio Awards-IV-2-16 covers P207 operation codes) [other_primary]
- Locator
- officialmilitaryribbons.com 'YMS 473:' listing block (5 operation lines); NAVPERS-15790 Part IV ship list
- Finding type
- historical_record
- Finding
- Official campaign-participation credit for this hull - all within post-surrender Minesweeping Operations Pacific (P207), no combat or assault-landing credit listed: P207-14 'Arcadia' (Kyushu-Korea Area) 1-5 Sep 1945; P207-13 Sasebo (Kyushu-Korea Area) 9-30 Sep 1945; P207-18 Fukuoka (Kyushu-Korea Area) 18-28 Oct 1945 and 9-27 Nov 1945; P207-10 Kure-Hiroshima (Honshu Area) 12 Jan-20 Feb 1946. Corroborates the deck-log Sasebo presence (ev-04) and dates her occupation-era sweeping service in Japanese and Korean waters.
- Verification
- partial
- Role
- context
- Documentation level
- ship_specific
- Accessed
- 2026-10-04
- Study period
- 1945-1946
- Population
- U.S. Navy crew of YMS-473 during listed operation windows (Sep 1945-Feb 1946)
- Limitations
- Cited via a commercial mirror page that reproduces NAVPERS-15790 verbatim ('Information obtained from Navy and Marine Corps Awards Manual NAVPERS 15,790 (Rev. 1953)'); the manual's underlying ship-list page was not directly retrieved - the HyperWar transcription covers the P207 operation-code list but not the per-ship index. Participation credit establishes presence in designated areas, not individual exposure. Contains no asbestos content.
- Atlas source
- true
- Evidence ID
- ev-uss-yms-473-05
-
[7]SCAPIN-4, 'Intended Minesweeping Operations by American Naval Forces in Japanese Waters,' Office of the Supreme Commander for the Allied Powers, 3 September 1945 (Nagoya University SCAP database); corroborated by USNI Proceedings, 'The United States Navy in Japan, 1945-1950' (April 1952) [other_primary]
- Locator
- SCAPIN-4 text paragraphs 1a-1c (Nagoya Univ. jahis.law.nagoya-u.ac.jp); usni.org/magazines/proceedings/1952/april/united-states-navy-japan-1945-1950
- Finding type
- historical_record
- Finding
- The operation framework this hull's campaign credits fall under: SCAPIN-4 notified Japan that 'a minesweeping group will soon start operations in SASEBO area,' with the advance base established 8 September 1945 at Arika Wan/Goto Retto and sweeping at Kii Suido from about 12-14 September. The USNI account documents the scale - over 10,000 U.S.-laid mines and 55,000+ Japanese-sown mines in Japanese waters and the Inland Sea - and the Navy's major shore establishments at former naval bases Yokosuka and Sasebo that supported the occupation sweeping effort.
- Verification
- verified
- Role
- context
- Documentation level
- context_only
- Accessed
- 2026-10-04
- Study period
- 1945-1950
- Population
- Allied and Japanese minesweeping personnel, Japanese home waters, 1945-46
- Limitations
- Operation-level context only - documents the sweeping campaign's existence, scale and schedule, not this hull's specific participation (which rests on ev-04/ev-05). Contains no asbestos or material content.
- Atlas source
- true
- Evidence ID
- ev-uss-yms-473-06
-
[8]Defense Today (디펜스투데이, Korean defense press), 'Naval mine-warfare vessels introduced 1946-1975' (Aug 2022; archived copy - live page now 404), citing ROK Navy sources; corroborated by Wikipedia 'List of ships of the Republic of Korea Navy' ship table (Gowon, YMS-517, ex-USS YMS-473) [reputable_press]
- Locator
- Defense Today article '고원정' narrative passage and fleet table row (고원 | 1947-08-30 | 1948-05-15 월북 | USS YMS-473); en.wikipedia.org/wiki/List_of_ships_of_the_Republic_of_Korea_Navy row 517
- Finding type
- vessel_history
- Finding
- Korean-service record for this hull: the Korean Coast Guard (조선해안경비대, predecessor of the ROK Navy, formally established September 1948) received 17 ex-U.S./British YMS hulls gratis January-August 1947, delivered already-decommissioned and disarmed (3-inch gun, 20 mm mounts, depth charges, sweeping gear removed). 고원 (Gowon), ex-USS YMS-473, was acquired 30 August 1947 per the article's fleet table (the ROKN ship list gives 6 August 1947 acquisition, 11 November 1947 commissioning, pennant YMS-517). 'On 15 May [1948], while on guard duty at Mukho, some of Gowon-jeong's crew staged an onboard mutiny and forcibly crossed to North Korea' - the ROKN list records 'Abducted to N. Korea,' loss date 1948-05-15. This was the second May 1948 naval defection, five days after the South Korean constituent elections: the tug-minelayer Tongcheon had been defected 7 May.
- Verification
- verified
- Role
- supporting
- Documentation level
- ship_specific
- Accessed
- 2026-10-04
- Study period
- 1947-1948
- Population
- Korean Coast Guard/ROKN crew of Gowon (1947-48); mutineer and non-mutineer crew on 15 May 1948
- Limitations
- Korean-language secondary sources - Defense Today cites ROK Navy headquarters material; the ROKN ship list is a maintained tabulation consistent with it. '월북' (crossed north) / 함상반란 (onboard mutiny) wording establishes the loss mechanism precisely; whether non-mutineer crew were taken against their will is not detailed. North Korean-era disposition undocumented. Live defensetoday.kr URL now returns 404 - archived Wayback capture (2022-09-30) cited. No asbestos content.
- Atlas source
- true
- Evidence ID
- ev-uss-yms-473-07
-
[9]Cross-source comparison: NavSource YMS-473 page and shipbuildinghistory ledgers ('sunk in 1948' / 'Ko Won, sunk 1948') vs Defense Today fleet narrative and ROKN ship list ('Abducted to N. Korea,' 1948-05-15); shipbuildinghistory type ledger BYMS-18 row ('To South Korea as YMS-517, scrapped') vs ROKN list and namu.wiki (Gyeongsan, YMS-515, wrecked Feb 1948) [other_primary]
- Locator
- NavSource 11/19473.htm; shipbuildinghistory.com/smallships/ym.htm (YMS-473 and BYMS-18 rows); defensetoday.kr fleet table; en.wikipedia.org/wiki/List_of_ships_of_the_Republic_of_Korea_Navy
- Finding type
- historical_record
- Finding
- CORRECTION: the standard Western register entries render this hull's fate 'sunk in 1948' (NavSource) / 'sunk 1948' (shipbuildinghistory). Korean documentation shows the loss year is right but the mechanism is wrong: she was lost to South Korea by crew mutiny at Mukho on 15 May 1948, taken into North Korean hands - not sunk. Separately, shipbuildinghistory's type ledger assigns the pennant 'YMS-517' to a different ex-hull (BYMS-18); the BYMS-18 hull is documented as ROKN Gyeongsan (YMS-515), wrecked at Biyangdo February 1948, while ex-YMS-473's YMS-517 pennant is corroborated by NavSource, the ROKN ship list, and Korean fleet records.
- Verification
- verified
- Role
- correction
- Documentation level
- ship_specific
- Accessed
- 2026-10-04
- Study period
- 1948 (loss window)
- Limitations
- Corrects a loss-mechanism error and flags a pennant-number conflation in secondary registers; does not resolve the hull's North Korean-era service or final disposition, which remain undocumented. Not an asbestos finding.
- Atlas source
- true
- Evidence ID
- ev-uss-yms-473-08
-
[10]NavSource Online: Auxiliary Motor Minesweeper (YMS) index - type history and construction program (verified live) [other_primary]
- Locator
- NavSource 11/19idx.htm 'Auxiliary Motor Minesweepers (YMS)' narrative paragraphs
- Finding type
- historical_record
- Finding
- Class context for this hull: the YMS type was a wooden minesweeper designed by Henry B. Nevins, Inc. (YMS-1 laid down 4 March 1941 at City Island, NY); 561 built at 35 yacht yards rather than larger shipyards - 12 on the East Coast, 19 on the West Coast, four in the Great Lakes. 'The wood-hulled YMS proved to be one of the U.S. Navy's more durable and versatile types.' The only significant variation was appearance: 'YMS-446 through YMS-479 had [no stacks]' - this hull's PCS-conversion subclass. Used for inshore sweeping; surviving YMS were reclassified AMS in 1947.
- Verification
- verified
- Role
- context
- Documentation level
- class_or_era
- Accessed
- 2026-10-04
- Study period
- 1941-1969
- Population
- YMS construction yard trades (1941-45); U.S. Navy YMS crews
- Limitations
- Class-level secondary compilation - supports type characteristics (wooden hull, diesel plant, yacht-yard construction) but names no materials aboard this hull. Hull count given as 561 built / 'all 481 ships of this type' (the 481 figure refers to U.S.-commissioned YMS after BYMS/Lend-Lease subtractions). Contains no asbestos content.
- Atlas source
- true
- Evidence ID
- ev-uss-yms-473-09
-
[11]Era inference built on: NavSource YMS-473 specifications (wooden YMS-type hull, two GM 8-268A diesels, Snow and Knobstedt reduction gear, two shafts - no steam plant); NavSource YMS index (wood-hulled, yacht-yard construction); GAO HRD-80-2 (Navy asbestos-use era, see ev-11) [other_primary]
- Locator
- NavSource 11/19473.htm specifications block; NavSource 11/19idx.htm class narrative; GAO HRD-80-2 (ev-11)
- Finding type
- asbestos_application
- Finding
- A wooden-hulled diesel minesweeper built 1943-44 inside the Navy's documented asbestos-use era would have carried era-standard diesel-era applications: thermal insulation on diesel exhaust lines and mufflers, engine gaskets and packing, valve packing, and electrical insulation in the small engineering spaces. With no steam plant - no boilers, no steam lines - and a wooden hull, the insulation footprint was materially smaller than aboard steam-driven steel warships; the boiler/turbine lagging pathway does not apply.
- Verification
- inferred
- Role
- supporting
- Documentation level
- class_or_era
- Accessed
- 2026-10-04
- Study period
- 1943-1948
- Population
- Harbor Boatbuilding construction trades (1943-44); U.S. Navy crew (1944-46); Korean Coast Guard/ROKN crew (1947-48); North Korean crew (1948-)
- Limitations
- Class/era inference only - no hull-specific insulation survey, material list, or work package located for YMS-473. Names era-standard applications, not confirmed installed materials; no quantity and no manufacturer attribution. The wooden hull reduces but does not eliminate the plausible scope (engine exhaust lagging and gasket/packing materials remain era-standard).
- Atlas source
- true
- Evidence ID
- ev-uss-yms-473-10
-
[12]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 (1943-44) and U.S. service era (1944-46).
- 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; supports era context only, not any fact specific to this hull - a wooden diesel minesweeper's asbestos footprint was smaller than the steam-plant fleet the report principally addresses. Full text not retrieved (gao.gov blocks automated fetch, HTTP 403) - content via product-page description.
- Atlas source
- true
- Evidence ID
- ev-uss-yms-473-11
-
[13]Batch-8361 search ledger (this record): NavSource hull page and YMS index; uboat.net; shipbuildinghistory type and yard ledgers; NARA catalog + digitized muster-roll file; NAVPERS-15790 mirror; SCAPIN-4; USNI Proceedings; Defense Today/Wayback + ROKN ship list; GAO product page; CourtListener (see search_ledger for session status); secondary web litigation sweep [other_primary]
- Locator
- search_ledger rows sl-uss-yms-473-01 through sl-uss-yms-473-12
- Finding type
- historical_record
- Finding
- No qualifying ship-specific asbestos record located: no asbestos survey, abatement contract, hazmat disclosure, museum/curatorial material record, or verified litigation naming YMS-473 or PCS-1443 was found in the public sources searched (see search_ledger). The digitized NARA file is personnel/muster material with no material content. Secondary web sweeps surfaced only law-firm marketing listicles asserting asbestos aboard WWII naval vessels generically - excluded by source policy.
- 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 - era-consistent inference remains reasonable. CourtListener session status is recorded in search_ledger; if blocked, the litigation repository check is an open gap, not a negative result. Does not establish or defeat any claim of exposure or legal eligibility for crew, builders, or Korean-service personnel.
- Atlas source
- true
- Evidence ID
- ev-uss-yms-473-12