Evidence
9 evidence entries recorded; each entry has a stable permalink (#ev-1 … #ev-9).
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[1]research packet 1036-packet.md [other_primary]
- Finding type
- vessel_history
- Finding
- Identity packet verdict: VERIFIED (thin sourcing
- Verification
- verified
- Role
- supporting
- Documentation level
- ship_specific
- Limitations
- qualifier: VERIFIED (thin sourcing
- Evidence ID
- uss-yms-177-yms177-pkt-1036-packet-md
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[2]NavSource Online: Mine Warfare Vessel Photo Archive, YMS-177 page (construction timeline, specifications, disposition, commanding officer, photo captions) [other_primary]
- Locator
- NavSource 11/19177.htm header timeline, specifications block, commanding-officer table, Terminal Island photo caption, DANFS note
- Finding type
- vessel_history
- Finding
- Documented for this hull (NavSource timeline): laid down 7 September 1942 by Henry C. Grebe and Co., Chicago, IL; launched 20 March 1943; completed 18 July 1943; present in Tokyo Bay during the Japanese surrender ceremony in September 1945; struck from the Naval Register 25 September 1946; transferred to the War Shipping Administration in January 1948; fate unknown. Call sign Nan-Yoke-Sugar-Mike. Specifications: displacement 270 t; length 136'; beam 24'6"; draft 8'; speed 13 kts; complement 32; armament one 3"/50 dual-purpose gun mount, two 20mm mounts, two depth-charge projectors; propulsion two 880bhp General Motors 8-268A diesel engines, Snow and Knobstedt single reduction gear, two shafts. Commanding officer listed: LTJG H. F. Seaman, USNR (1945). Page caption documents YMS-177 moored astern of YMS-53 and YMS-198 at Terminal Island, CA c. March 1946. Page states: 'There is no DANFS History currently available for YMS-177.'
- Verification
- verified
- Role
- context
- Documentation level
- ship_specific
- Accessed
- 2026-10-04
- Study period
- 1942-1948
- Population
- Grebe construction trades (1942-43); crew c. 32 (1943-46); Terminal Island lay-up population (1946)
- Limitations
- NavSource is a volunteer secondary compilation, not a primary registry - milestone dates generally track NVR/DANFS and are corroborated by secondary registries (uboat.net, shipbuildinghistory) but no primary commissioning document was located; 'Completed 18 July 1943' is carried over 'commissioned' because numbered YMS craft were placed in service. Contains no asbestos content. 'Fate unknown' means the post-1948 disposition is undocumented, not that disposal is proven.
- Atlas source
- true
- Evidence ID
- ev-uss-yms-177-01
-
[3]NHHC Navy Department Library, 'Allied Ships Present in Tokyo Bay During the Surrender Ceremony, 2 September 1945' (source: CINCPAC/CINCPOA A16-3/FF12 Serial 0395, 11 February 1946, Report of Surrender and Occupation of Japan; additions/subtractions from war diary, deck log and other sources) [nhhc_danfs]
- Locator
- NHHC page, Motor Mine Sweeper (YMS) section; source note at page foot
- Finding type
- vessel_history
- Finding
- YMS-177 is named on the official U.S. Navy list of Allied ships present in Tokyo Bay during the surrender ceremony of 2 September 1945, in the Motor Mine Sweeper (YMS) section alongside YMS-268, YMS-276, YMS-343, YMS-362, YMS-371, YMS-390, YMS-415, YMS-426, YMS-441, YMS-461 and YMS-467. The list derives from the CINCPAC/CINCPOA report Serial 0395 (11 February 1946) as adjusted against war diaries and deck logs.
- Verification
- verified
- Role
- context
- Documentation level
- ship_specific
- Accessed
- 2026-10-04
- Study period
- 1945-09-02
- Population
- YMS-177 ship's company (~32) present at the surrender ceremony
- Limitations
- Presence-at-ceremony documentation only - establishes the hull was in Tokyo Bay on 2 September 1945, nothing about operations, condition, or materials. No asbestos content.
- Atlas source
- true
- Evidence ID
- ev-uss-yms-177-02
-
[4]Diary of Edward (Ray) Mitchell, signalman, USS YMS-180 - NavSource-hosted first-person crew memoir, 'Journey Through the Mine Field' (verbatim transcription) [other_primary]
- Locator
- NavSource 11/19180d.htm, diary entries 23 May 1944, 14-16 Sep 1944, 19-21 Sep 1944, Oct 1944, 1-14 Nov 1944, 9 Mar 1945
- Finding type
- historical_record
- Finding
- A squadronmate's dated memoir names YMS-177 repeatedly in 1944-45 operations: on 23 May 1944 YMS-177 joined YMS-180 southbound from Little Creek, VA, for the Panama Canal Zone; on 14 September 1944 (~2300) YMS-180 departed the convoy with YMS-140 and YMS-177 for Anguar Island; on 15 September (D-Day for the southern Palaus assault, 0830 landings on Peleliu) the three swept in toward Anguar behind streamed magnetic gear; on 16 September they swept Kossol Passage (about eight mines destroyed by the group); on 19-21 September the unit - four YMS, four AM, and destroyer-minecraft Montgomery (DM-17, COMINRON ONE flagship, Capt. Clark) and Preble (DM-20) - moved to Ulithi, where on 21 September YMS-180 followed YMS-324, YMS-325 and YMS-177 into the lagoon to sweep. At Ulithi in October 1944 YMS-177 lent YMS-180 anchor chain after the early-October typhoon and on 12 October YMS-180 disposed of four mines YMS-177 had cut; about 1 November YMS-177 lay alongside a repair ship (Nestor); on 3 November the two practiced paired 'cantinary' (cantilever) sweeping; on 9 March 1945 YMS-180 met 'our sister ship the YMS-177' again at Ulithi.
- Verification
- partial
- Role
- context
- Documentation level
- ship_specific
- Accessed
- 2026-10-04
- Study period
- 1944-05-23 to 1945-03-09
- Population
- YMS-177 crew (~32); YMS-180, YMS-140, YMS-324, YMS-325 crews; MinRon One staff
- Limitations
- First-person enlisted memoir of a sister ship hosted on NavSource - presence and shared-operations detail for this hull is credible but is participant memory, not an official record; exact dates and counts are as the diarist recorded them. Covers only the period the two hulls operated together (May 1944 - March 1945); YMS-177's subsequent operations (Okinawa, Japanese home waters) are outside its scope. No asbestos content.
- Atlas source
- true
- Evidence ID
- ev-uss-yms-177-03
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[5]National Archives, Special List 44 - List of Logbooks of U.S. Navy Ships, Stations, and Miscellaneous Units, 1801-1947 (by-ship-numbers volume), YMS-177 entry [other_primary]
- Locator
- sl-44-ship-number.pdf, PDF page 116 ('Special List #44, by Ship Numbers' table), YMS-177 row
- Finding type
- historical_record
- Finding
- Special List 44 records U.S. Navy deck logs for YMS-177 covering 10/1/1943 to 6/30/1945 - a physical logbook accession at the National Archives, not a digitized series. The coverage window is the finding aid's record of holdings, not the ship's service dates (the hull was in service through at least September 1946).
- Verification
- verified
- Role
- archival_lead
- Documentation level
- ship_specific
- Accessed
- 2026-10-04
- Study period
- 1943-10-01 to 1945-06-30 (coverage window)
- Population
- N/A - finding aid
- Limitations
- Archival lead only - establishes that deck logs for this hull exist at NARA for the stated window; the logs themselves are not digitized and were not reviewed. Coverage ends 6/30/1945 while the ship remained active (Tokyo Bay, September 1945), so post-June-1945 logs are an open archival lead. No asbestos content in the finding aid itself.
- Atlas source
- true
- Evidence ID
- ev-uss-yms-177-04
-
[6]ShipbuildingHistory (T. Colton), 'Yard Minesweepers (YMS and BYMS)' construction table; corroborated by uboat.net Allied Warships entry for USS YMS-177 (ship 9599) [other_primary]
- Locator
- shipbuildinghistory.njscuba.net/us-navy-small/ym/, YMS-177 row; web.archive.org capture of shipbuildinghistory.com yms.htm; uboat.net/allies/warships/ship/9599.html
- Finding type
- vessel_history
- Finding
- Secondary registries corroborate the build record: shipbuildinghistory lists 'YMS-177 | Henry C. Grebe & Co. | Chicago IL | 136 | 320 | 18 Jul 1943 | struck 1946'; its earlier archived table reads 'YMS 177 | Henry C. Grebe & Co. | Mk. II | 18-Jul-43 | Struck 1946, disposition unknown'. uboat.net lists: ordered 14 March 1942; laid down 7 September 1942; launched 20 March 1943; commissioned 18 July 1943; stricken 25 September 1946. The builder ran a wartime series of YMS hulls at Chicago (YMS-84/85, YMS-171 through YMS-182, YMS-279/280, YMS-405 through YMS-409, YMS-418 through YMS-421, per the same tables).
- Verification
- verified
- Role
- context
- Documentation level
- ship_specific
- Accessed
- 2026-10-04
- Study period
- 1942-1948
- Population
- Grebe yard workforce (1942-43)
- Limitations
- Secondary compilation only - registry data used to corroborate NavSource milestones, not as a primary source; '320' (shipbuildinghistory) vs '270 t' (NavSource) is a displacement-basis difference (full load vs light/standard) not resolved by a primary spec sheet. No asbestos content.
- Atlas source
- true
- Evidence ID
- ev-uss-yms-177-05
-
[7]Era inference built on: NavSource specifications (2 x 880bhp GM 8-268A diesels, two shafts; wooden-hulled YMS-1 class, 136 ft); shipbuildinghistory class table; GAO HRD-80-2 Navy asbestos-era documentation (see ev-uss-yms-177-06) [other_primary]
- Locator
- NavSource 11/19177.htm specifications block; shipbuildinghistory YMS table; GAO HRD-80-2 product page
- Finding type
- asbestos_application
- Finding
- A diesel-powered wooden-hulled motor minesweeper built 1942-43 sits inside the Navy's documented asbestos-insulation era; era-standard applications aboard a small combatant of this type and period were engine and diesel-exhaust lagging, gaskets, valve and machinery packing, electrical insulation, and general insulation felts in the machinery space and accommodation of a 136-ft hull. As a diesel craft she carried no boilers or steam plant - the boiler/turbine lagging pathway of steam vessels does not apply.
- Verification
- inferred
- Role
- supporting
- Documentation level
- class_or_era
- Accessed
- 2026-10-04
- Study period
- 1942-1948
- Population
- Grebe construction trades (1942-43); crew (~32) in confined machinery spaces; any maintenance/overhaul trades 1943-46; disposal workforce (1948)
- Limitations
- Class/era inference only - no hull-specific insulation survey, material list, or work package located for YMS-177. Names era-standard applications, not confirmed installed materials. No quantity. Product names are normalized era terms; no manufacturer attribution for this hull. Wooden hull construction limits (but does not eliminate) structural insulation scope relative to steel combatants.
- Atlas source
- true
- Evidence ID
- ev-uss-yms-177-06
-
[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 (1942-43) and service era (1943-46).
- 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. Full text not retrieved (gao.gov returns HTTP 403 to automated fetch, confirmed 2026-10-04) - content via product-page description; same standing defect noted in BATCH-01/BATCH-98.
- Atlas source
- true
- Evidence ID
- ev-uss-yms-177-07
-
[9]Batch-8839 search ledger (this record): NavSource YMS-177 page and YMS-180 memoir; NHHC Tokyo Bay list (live); NARA Special List 44 ship-numbers PDF (verified live, PDF p.116); NARA digitized-deck-logs index; shipbuildinghistory and uboat.net registries; CourtListener exact-name opinion + docket queries; secondary web litigation sweep [other_primary]
- Locator
- search_ledger rows sl-uss-yms-177-01 through -15
- Finding type
- historical_record
- Finding
- No qualifying ship-specific asbestos record located: no asbestos survey, abatement contract, hazmat disclosure, or verified litigation naming YMS-177 was found in the public sources searched. CourtListener base queries completed: exact-name opinion ('USS YMS-177', type=o) returned 4 hits, all name collisions (an admiralty case on a different hull, YMS-12, and three OCR-garbage Texas appellate opinions); exact-name docket ('USS YMS-177', type=r) returned 893 free-text hits, first-page results all unrelated dockets with no vessel named - generic token matches, not case-name hits. CAVEAT: the hull-number queries ('YMS-177' type=o and type=r) could not be completed this session - CourtListener fleet pacing limiter stood the account down; logged as blocked in search_ledger, not as a negative result. The 893-hit docket overflow qualifies an asbestos-qualified variant query, which likewise could not be run. Secondary web sweeps surfaced no qualifying case and no marketing-source assertion naming this hull.
- 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 inference remains. The litigation repository search is a genuine open gap (hull-number queries and the asbestos-qualified docket variant paced, not run); deck logs (NARA, 10/1943-6/1945), builder records, and WSA/MARAD disposal files are undigitized leads. Does not establish or defeat any claim of exposure or legal eligibility.
- Atlas source
- true
- Evidence ID
- ev-uss-yms-177-08