Evidence
10 evidence entries recorded; each entry has a stable permalink (#ev-1 … #ev-10).
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[1]research packet 1068-packet.md (3 sources cited) [other_primary]
- Finding type
- vessel_history
- Finding
- Identity packet verdict: VERIFIED
- Verification
- verified
- Role
- supporting
- Documentation level
- ship_specific
- Evidence ID
- uss-yms-427-yms427-pkt-1068-packet-md
-
[2]NavSource Online: Mine Warfare Vessel Photo Archive, YMS-427 page - construction milestones, service record, specifications, disposal (verified live) [other_primary]
- Locator
- NavSource 11/19427.htm header block, service narrative, specifications block, CO table
- Finding type
- vessel_history
- Finding
- Documented for this hull: laid down 4 November 1943 by Mojean and Erickson, Tacoma, WA; launched 25 March 1944; completed and commissioned 28 November 1944. Assigned to the 1st Fleet in March 1945, serving in the assault and occupation of Okinawa Gunto 24 March - 30 June 1945; damaged by shore battery 7 April 1945 off Okinawa. Post-war minesweeping: Nagoya (Honshu area) and Sasebo (Kyushu-Korea area) 9 September - 26 October 1945; Kure-Hiroshima (Honshu area) 27 October 1945 - 26 February 1946. Deferred disposal status August 1946; decommissioned 12 November 1946; struck from the Naval Register 25 February 1947; transferred to the War Shipping Administration 9 December 1947 and sold to the American Tug Boat Co. of Nordland, WA; fate unknown. Spec block: displacement 270 t; length 136'; beam 24'6"; draft 8'; speed 15 kts; complement 32; armament one 3"/50 DP mount, two 20mm mounts, two depth charge projectors; propulsion two 880-bhp GM 8-268A diesels, Snow and Knobstedt single reduction gear, two shafts. Commanding officer listed: LTJG G. L. Denton, Jr., USNR (1945). Page states no DANFS history exists for YMS-427.
- Verification
- verified
- Role
- context
- Documentation level
- ship_specific
- Accessed
- 2026-10-04
- Study period
- 1943-1947
- Population
- Mojean & Ericson construction trades (1943-44); crew complement 32 (1944-46); WSA/commercial conversion crews (1947+)
- Limitations
- NavSource is a volunteer secondary compilation that tracks official sources - the decommissioning, striking, and sale dates are corroborated by uboat.net, and the 7 April 1945 shore-battery damage is corroborated by DANFS (Device entry, ev-03), but NavSource's 'assigned to the 1st Fleet' formulation is unexplained (see gaps). The post-war Japanese-waters sweep dates are NavSource-only. Contains no asbestos or material content.
- Atlas source
- true
- Evidence ID
- ev-uss-yms-427-yms427-01
-
[3]National Archives, Special List 44: List of Logbooks of U.S. Navy Ships, Stations, and Miscellaneous Units, 1801-1947 (ship-number listing, PDF page 121) [other_primary]
- Locator
- sl-44-ship-number.pdf, PDF page 121, 'YMS-427 11/28/1944 12/31/1945'
- Finding type
- historical_record
- Finding
- NARA's Special List 44 inventories deck logs for YMS-427 covering 11/28/1944 - 12/31/1945 (RG 24, Bureau of Naval Personnel records). Logbooks of this era record daily activity, disciplinary hearings, sick lists, and occasional injuries - the primary unexploited primary-source record for this hull's wartime service, including the 7 April 1945 shore-battery damage event.
- Verification
- verified
- Role
- archival_lead
- Documentation level
- ship_specific
- Accessed
- 2026-10-04
- Study period
- 1944-1945
- Population
- Crew (1944-45)
- Limitations
- Inventory listing only - establishes that logs exist and their coverage window, not their content; the logs themselves were not reviewed. Coverage ends 31 December 1945; any 1946 logbooks (through the 12 November 1946 decommissioning) are held in post-1941 accessions at NARA College Park and are not on this list. The logs are NOT digitized - no YMS-427 entry exists in NARA's online deck-logs index (see sl-11). No asbestos content.
- Atlas source
- true
- Evidence ID
- ev-uss-yms-427-yms427-02
-
[4]DANFS, Device (AM-220) - Okinawa service narrative naming YMS-427 (verified live) [nhhc_danfs]
- Locator
- DANFS Device (AM-220) narrative, Okinawa paragraph (events of 6-8 April 1945)
- Finding type
- vessel_history
- Finding
- Official DANFS record naming this hull: during the Okinawa operation, after USS Device (AM-220) rescued 16 survivors of the crashed USS Mullaney (DD-528) during the suicide attacks of 6 April 1945, 'the next day she helped YMS-427 extinguish a fire raging on board as a result of the service craft having been struck by shore gunfire' - i.e., on 7 April 1945 YMS-427 was struck by Japanese shore gunfire off Okinawa and suffered a fire aboard, which Device helped extinguish. Corroborates NavSource's 'damaged by shore battery 7 April 1945 off Okinawa.'
- Verification
- verified
- Role
- context
- Documentation level
- ship_specific
- Accessed
- 2026-10-04
- Study period
- 1945
- Population
- YMS-427 crew (April 1945); Device damage-assistance party
- Limitations
- Ship-specific mention inside another vessel's DANFS entry - documents the combat-damage event (hit by shore gunfire, resulting fire, assistance from Device) but not damage extent, casualties, or repairs. No asbestos or material content; a battle-damage-and-repair event is, however, the classic material-disturbance pathway for era-installed insulation.
- Atlas source
- true
- Evidence ID
- ev-uss-yms-427-yms427-03
-
[5]NHHC, U.S. Pacific Fleet Organization, 1 May 1945 (Navy Department Library) - minecraft order of battle (verified live) [other_primary]
- Locator
- Mine Squadron TWENTY section, YMS block: '| YMS 427 | (1) | Lt. (jg) G. L. Denton, Jr. (USNR) |'
- Finding type
- vessel_history
- Finding
- The 1 May 1945 Pacific Fleet organization lists YMS 427 under Commander Minecraft, Pacific Fleet (R. Adm. A. Sharp) in the Mine Squadron TWENTY section (Comdr. Mine Squadron TWENTY: Capt. R. A. Larkin), with flag '(1)' and commanding officer Lt. (jg) G. L. Denton, Jr. (USNR) - corroborating NavSource's CO listing and placing the hull in the Pacific Fleet minecraft order of battle during the Okinawa campaign.
- Verification
- verified
- Role
- context
- Documentation level
- ship_specific
- Accessed
- 2026-10-04
- Study period
- 1945
- Population
- Crew (May 1945)
- Limitations
- Establishes administrative assignment and CO as of 1 May 1945 only. The '(1)' flag's legend is not decoded in the published page text; the YMS block carries no MinDiv number for this hull. No asbestos or material content. NavSource's separate '1st Fleet' wording is not resolved by this document (see gaps).
- Atlas source
- true
- Evidence ID
- ev-uss-yms-427-yms427-04
-
[6]NHHC photograph NH 84989, 'USS YMS-427 - In San Francisco Bay, circa 1945' (courtesy Donald McPherson, 1976); plus U.S. Naval War College Archives, MSC-385 item 100.9795, 'USS YMS-427, circa 1944' photo [museum_official]
- Locator
- NHHC NH 84989 catalog record; usnwcarchives.org/repositories/2/archival_objects/255712 (Vessels: Y-Z collection index listing item 100.9795)
- Finding type
- historical_record
- Finding
- Two archival photographs of this hull located: NH 84989 (NHHC) shows YMS-427 in San Francisco Bay circa 1945 - NavSource captions the same image 'sailing under the Golden Gate Bridge upon her return from Japan,' consistent with her early-1946 return from occupation-duty minesweeping; and the Naval War College Archives hold a second photo (item 100.9795, MSC-385 'Vessels: Y-Z, circa 1898-1944' collection, Box 43) cataloged as USS YMS-427, circa 1944.
- Verification
- verified
- Role
- archival_lead
- Documentation level
- ship_specific
- Accessed
- 2026-10-04
- Study period
- 1944-1946 (photo windows)
- Limitations
- Photographs only - visual documentation, no work or material record. NHHC date range (after 1940 / before 1949) and 'circa 1945' caption are broad. The NWC item-level record was confirmed via the collection index; the item page itself was not individually fetched. No asbestos content.
- Atlas source
- true
- Evidence ID
- ev-uss-yms-427-yms427-05
-
[7]Naval Marine Archive (mirroring shipbuildinghistory.com data), Mojean & Ericson yard table, Tacoma WA - builder hull list (verified live) [other_primary]
- Locator
- navalmarinearchive.com/sbh/shipyards/emergencysmall/mojean.html, yard description and build table
- Finding type
- vessel_history
- Finding
- The Mojean & Ericson yard table lists YMS 427 as a 278-ton-displacement, 136-ft US Navy minesweeper delivered 28 November 1944 (matching NavSource's completion/commissioning date), disposition 'Struck 1946.' Yard context: William Mojean and Olaf Ericson founded the yard in 1925 on the Thea Foss Waterway (East D Street) in Tacoma and closed it at the end of the war; its Navy output included YMS-222 through -225, PCS-1455/1456 (the latter completed as YMS-479), and YMS-426 through -431. The table assigns YMS 427 no post-Navy official number or merchant name - consistent with NavSource's 'fate unknown' (contrast sister YMS 429, documented sold 1947 as Princess Laverne, O.N. 258428).
- Verification
- verified
- Role
- context
- Documentation level
- ship_specific
- Accessed
- 2026-10-04
- Study period
- 1943-1947
- Population
- Mojean & Ericson construction trades (1943-44)
- Limitations
- Secondary shipbuilding-data compilation, not a primary registry - the 'Struck 1946' disposition conflicts with NavSource/uboat.net's struck date of 25 February 1947 (likely shorthand for out-of-commission; see gaps). Yard page corroborates the builder identity and delivery date only. No asbestos content; no yard asbestos record located.
- Atlas source
- true
- Evidence ID
- ev-uss-yms-427-yms427-06
-
[8]Era inference built on: NavSource spec block (YMS-1-class, wooden-hulled type; two 880-bhp GM 8-268A diesels, reduction gear, two shafts); NavSource YMS index class overview (wooden hulls, built at 35 yacht/small yards); GAO HRD-80-2 (Navy-wide asbestos use through early 1970s) [other_primary]
- Locator
- NavSource 11/19427.htm spec block; NavSource 11/19idx.htm class overview; GAO HRD-80-2 product page
- Finding type
- asbestos_application
- Finding
- A wooden-hulled diesel motor minesweeper built 1943-44 sits inside the Navy's documented asbestos-use era; era-standard asbestos applications aboard a small diesel combatant of this type were diesel exhaust lagging, gaskets, valve packing, electrical insulation, and limited thermal insulation in machinery spaces - in far smaller scope than steam-propelled vessels. As a diesel-engined wooden craft she carried no steam plant, so the boiler/turbine/steam-line lagging pathway of larger vessels does not apply; the small, enclosed machinery-space volume remains the relevant exposure geometry.
- Verification
- inferred
- Role
- supporting
- Documentation level
- class_or_era
- Accessed
- 2026-10-04
- Study period
- 1943-1947
- Population
- Mojean & Ericson construction trades (1943-44); crew (1944-46); commercial conversion crews post-1947 sale
- Limitations
- Class/era inference only - no hull-specific insulation survey, material list, or work package located for YMS-427. Names era-standard applications, not confirmed installed materials. No quantity. Product names are normalized era terms; no manufacturer attribution for this hull.
- Atlas source
- true
- Evidence ID
- ev-uss-yms-427-yms427-07
-
[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 to automated fetch)
- 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 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. The report's fieldwork focused on naval shipyards, not small contract yacht yards like Mojean & Ericson. Full text not retrieved (gao.gov blocks automated fetch, HTTP 403, consistent with prior batches) - content via product-page description.
- Atlas source
- true
- Evidence ID
- ev-uss-yms-427-yms427-08
-
[10]Batch-9067 search ledger (this record): NavSource vessel and class pages; DANFS Device entry; NHHC Pacific Fleet organization; NHHC NH 84989; NARA Special List 44 ship-number PDF; uboat.net; Naval Marine Archive yard table; NWC Archives collection index; CourtListener (authenticated helper, fleet-paced); secondary web litigation sweep [other_primary]
- Locator
- search_ledger rows sl-uss-yms-427-yms427-01 through -11
- Finding type
- historical_record
- Finding
- No qualifying ship-specific asbestos record located: no asbestos survey, abatement contract, hazmat disclosure, or litigation naming YMS-427 was found in the public sources searched (see search_ledger). All four CourtListener base queries (exact-name and hull-number across both opinion and RECAP docket indexes) returned zero hits - a clean negative, not a blocked search. The only 'asbestos aboard YMS' material in general web results is non-specific class-level or law-firm marketing content - 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 - and the deck logs, the builder's records, and any WSA-sale or commercial-conversion documents are undigitized leads. Does not establish or defeat any claim of exposure or legal eligibility.
- Atlas source
- true
- Evidence ID
- ev-uss-yms-427-yms427-09