USS YMS-418

Evidence

9 evidence entries recorded; each entry has a stable permalink (#ev-1 … #ev-9).

1. [1]NavSource Online: Mine Warfare Vessel Photo Archive, YMS-418 page - construction timeline, specifications, call sign, disposition, photograph [other_primary]

   Locator

   NavSource 11/19418.htm header block, specifications block, photo caption, DANFS note

   Finding type

   vessel_history

   Finding

   NavSource timeline for this hull: 'YMS-1 Class Auxiliary Motor Minesweeper'; call sign Nan-Peter-Yoke-Peter; laid down 16 September 1943 by Henry C. Grebe and Co., Chicago, IL; launched 22 February 1944; completed 21 September 1944; 'Struck from the Navy Register 7 February 1947'; 'Transferred to the War Shipping Administration 17 December 1947 and sold. Fate unknown.' Specifications: displacement 270 t.; length 136'; beam 24' 6"; draft 8'; speed 15 kts.; complement 32; armament one 3"/50 dual purpose gun mount, two 20mm mounts, and two depth charge projectors; propulsion two 880bhp General Motors 8-268A diesel engines, Snow and Knobstedt single reduction gear, two shafts. Page holds one photograph (c. 1945, San Francisco Bay, CA, Naval History and Heritage Command photo NH 79713, courtesy of D.M. McPherson 1974) and states 'There is no DANFS History currently available for YMS-418'.

   Verification

   verified

   Role

   context

   Documentation level

   ship_specific

   Accessed

   2026-10-04

   Study period

   1943-1947

   Population

   Grebe yard construction trades (1943-44); crew (1944-47); post-sale civilian owners (1947-)

   Limitations

   NavSource is a volunteer secondary compilation, not a primary registry - milestone dates generally track official records and are corroborated here by uboat.net, the awards manual, the Grebe yard table, and Special List 44. 'Completed 21 September 1944' is read as the in-commission date (consistent with uboat.net 'Commissioned'). Contains no asbestos content. The 'WSA' transfer wording is loose - WSA was abolished 1 September 1946 (see ev-08).

   Atlas source

   true

   Evidence ID

   ev-uss-yms-418-yms418-01

2. [2]uboat.net Allied Warships, USS YMS-418 (YMS-418) - build milestones, striking, disposal (secondary compilation) [other_primary]

   Locator

   uboat.net ship/9837 data table

   Finding type

   vessel_history

   Finding

   uboat.net record for this hull: built by Henry C. Grebe Co. (Chicago, Illinois, U.S.A.); ordered 21 July 1943; laid down 16 September 1943; launched 22 February 1944; commissioned 21 September 1944; 'Stricken on 7 February 1947'; 'Sold on 17 December 1947'. No events or commanding officers listed for the vessel.

   Verification

   verified

   Role

   context

   Documentation level

   ship_specific

   Accessed

   2026-10-04

   Study period

   1943-1947

   Population

   Grebe yard construction trades (1943-44); crew (1944-47)

   Limitations

   Secondary compilation - the only located source carrying an 'ordered' date (21 July 1943), which is otherwise uncorroborated; milestones otherwise agree exactly with NavSource and the Grebe yard table. Contains no asbestos content.

   Atlas source

   true

   Evidence ID

   ev-uss-yms-418-yms418-02

3. [3]National Archives, Special List 44 'List of Logbooks of U.S. Navy Ships, Stations, and Miscellaneous Units, 1801-1947' - ship-number index (archives.gov PDF) [other_primary]

   Locator

   sl-44-ship-number.pdf, PDF page 121, 'YMS-418' row (137-page PDF)

   Finding type

   historical_record

   Finding

   Special List 44's ship-number index inventories US Navy deck logs for this hull: 'YMS-418 10/11/1944 12/31/1945'. Deck logs covering 11 October 1944 through 31 December 1945 therefore exist in NARA custody (RG 24 deck-log series, College Park).

   Verification

   verified

   Role

   archival_lead

   Documentation level

   ship_specific

   Accessed

   2026-10-04

   Study period

   1944-10-11 to 1945-12-31 (inventory coverage)

   Population

   Crew (1944-45 log window)

   Limitations

   The dates are log-coverage inventory dates, not asserted commissioning/decommissioning dates - coverage begins 20 days after the documented completion date and ends before her striking (7 Feb 1947) and before the end of her credited Kobe-area minesweeping window (to 2 Mar 1946, ev-04), so later logs exist but are not itemized for this hull in this index. The deck logs are paper records; the NARA online digitized-deck-log index lists no YMS-418 entry (numbered vessels appear there only under later names, and this hull was never named). PDF page 121 verified by direct download and text extraction.

   Atlas source

   true

   Evidence ID

   ev-uss-yms-418-yms418-03

4. [4]Navy and Marine Corps Awards Manual, NAVPERS 15,790 (Rev. 1953), Part IV, Section 2(16) - official list of ships eligible for engagement stars (HyperWar transcription of the government manual) [other_primary]

   Locator

   Awards-IV-16.html Part IV Section 2(16) ship-eligibility list, 'YMS 418:' entry; Part III entries for P34, P35, and P207 sub-operations (operation names and windows)

   Finding type

   vessel_history

   Finding

   The official Navy awards list credits YMS-418 with six WWII engagements: 26 Jun 45 - '30 Jan 45' under P34-1 ('Assault and occupation of Okinawa Gunto', operation window 24 Mar - 30 Jun 45 - the printed end date is a manual typo; the identical credit for sister YMS-415 reads 26 Jun - 30 Jun 45); 5 Jul 45 - 31 Jul 45 under P35 ('3d Fleet operations against Japan', window 10 Jul - 15 Aug 45); 8 Sep 45 - 16 Sep 45 under P207-6 (Kochi-Shikoku, Honshu Area, window 8 Sep - 8 Nov 45); 22 Sep 45 - 30 Oct 45 under P207-7 (Bungo-Suido, Honshu Area, window 22 Sep - 31 Oct 45); 15 Dec 45 - 2 Mar 46 under P207-9 (Kobe, Honshu Area, window 28 Nov 45 - 9 Mar 46); and 14 Aug 45 - 24 Aug 45 under P207-23 ('Skagway', East China Sea-Ryukyus Area, window 14 Aug - 9 Nov 45). The four P207 sub-operations belong to 'Minesweeping Operations Pacific' (23 Jun 45 - 2 Mar 46; one star for participation in one or more) - the post-surrender clearance of Japanese-laid minefields in home waters.

   Verification

   verified

   Role

   context

   Documentation level

   ship_specific

   Accessed

   2026-10-04

   Study period

   1945-1946 (credited operations); manual published 1953

   Population

   Crew during Okinawa campaign closing phase (Jun 1945), 3d Fleet Japan operations (Jul 1945), East China Sea-Ryukyus sweeping (Aug 1945), and Japanese-home-waters mine clearance (Sep 1945 - Mar 1946)

   Limitations

   An award-eligibility list, not a unit history: it documents credited participation windows, not day-by-day activity, position, or task organization. The Naval History Division itself flagged hundreds of entry errors in this manual for other operations (1950s correspondence re: Leyte Gulf/Lingayen entries); YMS-418's '30 Jan 45' P34-1 end date is itself a typographical error (impossible window; YMS-415's parallel credit reads 30 Jun 45) carried verbatim and flagged, not corrected here. Dates verified in the actual transcription text, not via commercial ribbon-vendor reproductions. Contains no asbestos content.

   Atlas source

   true

   Evidence ID

   ev-uss-yms-418-yms418-04

5. [5]Shipbuilding History (T. Colton), Henry C. Grebe & Company yard page - yard history and hull-by-hull production table [other_primary]

   Locator

   shipbuildinghistory.com/shipyards/yachtsmall/grebe.htm yard table, YMS 418 row

   Finding type

   vessel_history

   Finding

   Builder context: Henry C. Grebe & Company was the successor to Great Lakes Boat Building, which had started in Milwaukee in 1915 and moved to Chicago in 1921; the yard stood on the west side of the North Branch of the Chicago River just north of the West Belmont Avenue Bridge, built its last boat in 1970, and did not finally close until 1994. The yard table lists YMS-418 among its wartime builds (Grebe's YMS blocks include YMS 84-85, YMS 171-182, YMS 279-280, YMS 405-409, and YMS 418-421), delivered 21-Sep-44, with disposition 'Sold 1947'.

   Verification

   verified

   Role

   context

   Documentation level

   ship_specific

   Accessed

   2026-10-04

   Study period

   1943-1947 (build window); yard history 1915-1994

   Population

   Grebe yard construction trades (1943-44)

   Limitations

   Secondary compilation - Colton's delivery date (21-Sep-44) and 'Sold 1947' agree with NavSource/uboat. The yard table does not give laid-down or launch dates for this hull. Contains no asbestos content; no yard-level asbestos documentation exists for this small yacht/boat yard (contrast: NIOSH-surveyed yards like Electric Boat).

   Atlas source

   true

   Evidence ID

   ev-uss-yms-418-yms418-05

6. [6]Era inference built on: NavSource specifications (2 x GM 8-268A diesels, Snow & Knobstedt gear, 2 shafts; YMS-1 class); class literature (wooden hulls built at 35 yacht/boat yards); GAO HRD-80-2 Navy asbestos-use era documentation (ev-07) [other_primary]

   Locator

   NavSource 11/19418.htm specifications block; YMS-1 class descriptions; shipyards.json has no Grebe entry

   Finding type

   asbestos_application

   Finding

   A wooden-hulled diesel-powered auxiliary minesweeper completed September 1944 sits inside the Navy's documented asbestos-use era. Era-standard applications aboard a small diesel combatant of this type were diesel-exhaust lagging and machinery insulation in the engine space, gaskets and valve packing throughout piping systems, electrical insulation and panelboard, and brake linings on the sweep winch and windlass. As a diesel vessel with a wooden hull she carried no steam plant - the boiler/turbine lagging pathway of steam vessels does not apply, and her asbestos loading would be materially lighter than a steam vessel of the era.

   Verification

   inferred

   Role

   supporting

   Documentation level

   class_or_era

   Accessed

   2026-10-04

   Study period

   1943-1947

   Population

   Grebe construction trades (1943-44); engine-room and repair-rated crew (1944-47); disposal/shipbreaking or civilian-owner trades post-1947

   Limitations

   Class/era inference only - no hull-specific insulation survey, material list, work package, or abatement record located for YMS-418. 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-418-yms418-06

7. [7]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 service era (1944-47).

   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 blocks automated fetch, HTTP 403, confirmed 2026-10-04) - content via product-page description.

   Atlas source

   true

   Evidence ID

   ev-uss-yms-418-yms418-07

8. [8]Disposition cross-check: NavSource 11/19418.htm ('Struck from the Navy Register 7 February 1947'; 'Transferred to the War Shipping Administration 17 December 1947 and sold'); uboat.net ship/9837 ('Stricken on 7 February 1947', 'Sold on 17 December 1947'); shipbuildinghistory.com Grebe yard table ('Sold 1947') [other_primary]

   Locator

   NavSource header disposition line; uboat.net 'History' field; Grebe yard table disposition column

   Finding type

   historical_record

   Finding

   DISPOSITION CLARIFICATION: all three compilations agree - stricken 7 February 1947, transferred and sold 17 December 1947 (no date conflict). One terminology correction: a December 1947 disposal could not have been administered by the War Shipping Administration, which was abolished effective 1 September 1946; the actual disposal agency was its successor, the U.S. Maritime Commission. NavSource's 'WSA' wording is loose usage for the successor disposal channel.

   Verification

   verified

   Role

   correction

   Documentation level

   ship_specific

   Accessed

   2026-10-04

   Study period

   1947 (disposition window)

   Population

   Disposal/shipbreaking or civilian-owner trades post-1947

   Limitations

   No registry-level document was located for the striking or disposal event (NVR excludes vessels disposed before 1987; no NVR entry exists; no DANFS entry exists). The buyer, flag, and ultimate fate of the hull after the December 1947 sale are unlocated - 'fate unknown' stands. No asbestos content.

   Atlas source

   true

   Evidence ID

   ev-uss-yms-418-yms418-08

9. [9]Batch-9057 search ledger (this record): NavSource; uboat.net; NARA Special List 44 ship-number PDF (p.121 verified); NARA online deck-log index; NAVPERS 15,790 (HyperWar transcription); shipbuildinghistory Grebe yard table; GAO product page; CourtListener (blocked); secondary web litigation sweep [other_primary]

   Locator

   search_ledger rows sl-uss-yms-418-yms418-01 through -13

   Finding type

   historical_record

   Finding

   No qualifying ship-specific asbestos record located: no asbestos survey, abatement contract, hazmat disclosure, or verified litigation naming USS YMS-418 was found in the public sources searched. CAVEAT: only 1 of the 4 prescribed CourtListener base queries could be run - exact-name opinion returned a single name-collision hit (In re Albert Ortiz, Tex. App.-Houston 14th Dist., 2015; full text contains no 'YMS-418'/'YMS'/'USS'/'vessel'/'asbestos' term - spurious index match, non-qualifying). The other three base queries remained blocked all session (fleet-wide pacing budget spent, ~58/hr shared across sessions); logged as blocked in search_ledger, not as a negative result. Secondary web sweeps surfaced no qualifying case and no hull-specific 'asbestos aboard' content for YMS-418 (generic asbestos-ship listicles exist - 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 3 of 4 prescribed litigation repository queries remain a genuine open gap (paced out, not run). The 10/11/1944-12/31/1945 deck logs, builder construction records, and any 1947 disposal/survey files are undigitized leads. Does not establish or defeat any claim of exposure or legal eligibility.

   Atlas source

   true

   Evidence ID

   ev-uss-yms-418-yms418-09