Evidence
7 evidence entries recorded; each entry has a stable permalink (#ev-1 … #ev-7).
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[1]National Archives, Special List 44: List of Logbooks of U.S. Navy Ships, Stations, and Miscellaneous Units, 1801-1947 (NARA, 1978), 'Ships by Signal Number Designation' T-Y section [other_primary]
- Locator
- SL44 printed p. 523, 'YMS-420 | Mar. 15-Aug. 31, 1945 | 1 [logbook]'; typeset PDF p. 121; ACPL mirror scan display=555
- Finding type
- historical_record
- Finding
- Special List 44 inventories US Navy deck logs for YMS-420 covering 15 March 1945 through 31 August 1945 (1 logbook) - a span covering her wartime window (completed and commissioned 5 February 1945 per NavSource; a six-week gap between commissioning and the first surviving log presumably reflects fitting-out/transit from the builder's Chicago yard).
- Verification
- verified
- Role
- archival_lead
- Documentation level
- ship_specific
- Accessed
- 2026-10-04
- Study period
- 1945 (log coverage); inventory published 1978
- Population
- YMS-420 crew, March-August 1945 (log coverage period)
- Limitations
- This is an inventory entry, not the logs themselves: it establishes that one logbook exists but not its contents - stations, operations, or any aboard conditions are unread here. YMS-420 does not appear on NARA's digitized deck-log index (archives.gov navy-online page searched 2026-10-04; YMS hulls appear there only under later named AMS conversions), so the log is an undigitized archival lead only (post-1940 logs held at Archives II, College Park). Entry verified on printed SL44 p. 523 (scan via ACPL Genealogy Center mirror, display p. 555) and on p. 121 of the typeset PDF reproduction.
- Atlas source
- true
- Evidence ID
- ev-uss-yms-420-01
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[2]NavSource Online: Mine Warfare Vessel Photo Archive, YMS-420 / HMCS Cordova (MCA 158) page (build/service/disposition chronology compiled from Navy Register and merchant documentation data) [other_primary]
- Locator
- YMS-420 chronology block and specifications
- Finding type
- vessel_history
- Finding
- YMS-1 Class Auxiliary Motor Minesweeper: laid down 18 September 1943 by Henry C. Grebe and Co., Chicago, IL; launched 8 April 1944; completed 5 February 1945 and commissioned USS YMS-420; 'Loaned to an unknown miscellaneous activity in February 1947'; struck from the Naval Register 31 January 1950; sold to Canada 3 December 1951; commissioned HMCS Cordova (MCA 158) 9 August 1952; decommissioned 4 April 1957; declared surplus 1963; sold 1970 to Harbour Ferries, Ltd. of Vancouver as Harbour Queen No. 1; Sea-Land Industries 1974, Eland Distributors 1975, Northwind Marine 1978; renamed Nakaya 1980; acquired 1984 by British Columbia, Ltd.; sunk as a diving wreck at Porteau Cove Provincial Park. Specifications: 270 t, 136 ft, 24 ft 6 in beam, 8 ft draft, 15 kt, complement 32; one 3"/50 dual-purpose mount, two 20mm mounts, two depth charge tracks; two 880-bhp General Motors 8-268A diesels, Snow and Knobstedt single-reduction gear, two shafts. Page states: 'There is no DANFS history available for YMS-420.'
- Verification
- verified
- Role
- context
- Documentation level
- ship_specific
- Accessed
- 2026-10-04
- Study period
- 1943-1985
- Population
- YMS-420 crew (wartime); RCN Cordova crew; merchant-era operators
- Limitations
- NavSource is a compiled secondary archive of official data, not the underlying registers; its 'sunk in 1992' date conflicts with DFO/ARSBC documentation giving 3 August 1985 (see ev-uss-yms-420-06 and gaps), and its 'decommissioned 4 April 1957' conflicts with canada.ca's paid-off date of 12 April 1957. Contains no asbestos information. WWII operational stations are not listed - service detail is undocumented in located sources.
- Atlas source
- true
- Evidence ID
- ev-uss-yms-420-02
-
[3]NavSource Online, Auxiliary Motor Minesweeper (YMS) index page - class description [other_primary]
- Locator
- YMS index class-description paragraphs
- Finding type
- vessel_history
- Finding
- The YMS type was a wood-hulled, diesel-powered inshore minesweeper designed by Henry B. Nevins, Inc.; 561 were built at 35 yacht yards (not major shipyards) - 12 East Coast, 19 West Coast, 4 Great Lakes. YMS-135 through YMS-445 (plus 480-481) were the single-stack variant, which includes YMS-420. Surviving YMSs still in naval service were reclassified AMS and named in 1947 - YMS-420 was not among them (struck 1950 while recorded as loaned out); she received no AMS designation or USN name.
- Verification
- verified
- Role
- context
- Documentation level
- class_or_era
- Accessed
- 2026-10-04
- Study period
- 1941-1969
- Population
- YMS-class crews and builders, 1941-1969 (class context)
- Limitations
- Class-level design context only: establishes wood hull and diesel propulsion (no boilers, no steam piping - the dominant asbestos-lagging pathway of steam ships is absent by design), but documents no asbestos or insulation material content for the class or this hull. Does not establish presence or absence of residual asbestos components (gaskets, wiring, brake linings).
- Atlas source
- true
- Evidence ID
- ev-uss-yms-420-03
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[4]shipbuildinghistory.com (Tim Colton), Henry C. Grebe & Company yard table, Chicago IL [other_primary]
- Locator
- Grebe yard table, YMS 420 row
- Finding type
- historical_record
- Finding
- The Grebe yard table lists 'YMS 420 | US Navy | Minesweeper | 320 | 136 | 5-Feb-45 | To RCC 1951 as Cordova (MCA 158), sold 1970 as Harbour Queen No. 1, Nakaya, reefed 1992' - confirming builder, delivery date (matching the commissioning date), and the post-Navy name chain. The yard (successor to Great Lakes Boat Building; on the west side of the North Branch of the Chicago River just north of the West Belmont Avenue Bridge; built its last boat 1970, closed 1994) also built YMS 84-85, 171-181, 418-421 and other YMS hulls.
- Verification
- verified
- Role
- context
- Documentation level
- ship_specific
- Accessed
- 2026-10-04
- Study period
- 1943-1945
- Population
- Henry C. Grebe & Co. construction trades, 1943-1945
- Limitations
- Compiler's table, not the underlying registry; 'RCC' is a typo for RCN, and 'reefed 1992' conflicts with DFO/ARSBC documentation of the 3 August 1985 scuttling (the 1992 figure matches the Canadian-register closure year - see ev-uss-yms-420-06 and gaps). Contains no asbestos information; establishes builder, delivery date, and post-Navy identity only.
- Atlas source
- true
- Evidence ID
- ev-uss-yms-420-04
-
[5]Government of Canada / Royal Canadian Navy, official ship history: HMCS Cordova (158), Yard-class Motor Minesweeper [other_primary]
- Locator
- HMCS Cordova ship-history page, text and data table (page modified 2020-10-21)
- Finding type
- vessel_history
- Finding
- Official RCN record: 'Cordova was launched as YMS.420 in 1944 at Chicago. She was purchased by the RCN on 3 December 1951, and commissioned from 9 August 1952 to 12 April 1957, serving primarily as tender to the Vancouver Naval Reserve Division. After being sold, she became the barge Harbour Queen and later the Nakaya. In 1985 she was sunk as a sport-divers' wreck in Howe Sound, BC.' Tabulated: builder H.C. Grebe & Co., Chicago IL; launched 8 April 1944; commissioned 9 August 1952; paid off 12 April 1957; displacement 325 tonnes; 41.5 m x 7.5 m x 2.4 m; speed 15 knots; crew 30.
- Verification
- verified
- Role
- context
- Documentation level
- ship_specific
- Accessed
- 2026-10-04
- Study period
- 1951-1985
- Population
- RCN Cordova crew, 1952-1957
- Limitations
- Official Canadian source covering the RCN period; gives paid-off 12 April 1957 (vs NavSource's 4 April 1957) and 'in 1985' sinking (vs the 1992 carried by NavSource and the Grebe yard table). Figures (325 tonnes, crew 30) are RCN-era and differ from USN class figures - see gaps. Contains no asbestos information.
- Atlas source
- true
- Evidence ID
- ev-uss-yms-420-05
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[6]B. Smiley, 'Intentional scuttling of surplus vessels and wrecks: some effects on marine biota and habitats in British Columbia waters' (Fisheries and Oceans Canada report, 2002), Nakaya/Porteau Cove entries; plus ARSBC field worksheet 'Porteau wrecks and reefs 2013' [other_primary]
- Locator
- DFO report: Nakaya narrative paragraph (~p. 37 of text), reef inventory table row 4 (49 33.60 N / 123 14.00 W), Appendix 18 (p. 101); ARSBC 'porteau_wrecks_and_reefs_2013.pdf' NAKAYA entry
- Finding type
- vessel_history
- Finding
- DFO documentation states: 'On August 3, 1985, the 41-metre wooden-hulled Nakaya was scuttled near the northern edge of the diving area at Porteau. Commissioned as the minesweeper Cordova, the vessel was retired in the 1950s and spent its final years as a floating camp.' The wreck lies at 49 deg 33.60 min N, 123 deg 14.00 min W, stern in ~18 m, bow in ~30 m. The ARSBC 2013 worksheet repeats the 3 August 1985 date and reports the wooden hull 'deteriorated significantly... no longer of much interest to divers.' This establishes the scuttling as August 1985 - the '1992' carried by NavSource, the Grebe yard table, and derived dive literature matches the year the Canadian register closed, not the sinking.
- Verification
- verified
- Role
- correction
- Documentation level
- ship_specific
- Accessed
- 2026-10-04
- Study period
- 1985-2013
- Population
- Recreational divers (1985-present); scuttling/preparation workers (1985, 1989)
- Limitations
- The DFO report's own reef-inventory table row prints '1986 August 03' for the Nakaya - a one-year internal discrepancy against its narrative ('August 3, 1985'), which is also the canada.ca figure and the ARSBC figure; 3 August 1985 is adopted. The report documents scuttling preparation (access holes, guide lines, float) for diver safety but records no asbestos, hazmat, or material assessment of the hull. Position and condition are as-surveyed at report time; present-day condition may be worse.
- Atlas source
- true
- Evidence ID
- ev-uss-yms-420-06
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[7]Batch-9060 search ledger (this record): NARA Special List 44 + digitized-log index; NavSource (hull page + class index); NHHC/DANFS; Naval Vessel Register; shipbuildinghistory Grebe yard table; canada.ca RCN ship history; DFO/ARSBC reef documentation; CourtListener opinion and docket search [other_primary]
- Locator
- search_ledger rows sl-uss-yms-420-01 through sl-uss-yms-420-14
- Finding type
- historical_record
- Finding
- No qualifying ship-specific asbestos record located: no DANFS entry exists (NavSource states none), no NVR detail page exists (vessel stricken 1950, outside NVR coverage; SHIPDETAILS URL returns the generic index), no asbestos survey/abatement/hazmat record exists for the hull or the Porteau Cove wreck, and no qualifying asbestos litigation naming YMS-420 was found in CourtListener opinion or docket search - all four base queries completed with zero hits (exact-name opinion, exact-name docket, hull-number opinion, hull-number docket; the hull-number docket query completed 2026-10-05 after fleet pacing saturation blocked it on 2026-10-04, see search_ledger sl-uss-yms-420-14).
- Verification
- verified
- Role
- negative_finding
- Documentation level
- ship_specific
- Accessed
- 2026-10-04
- Study period
- 2026-10-04 to 2026-10-05
- Limitations
- Absence of a located public record does not prove absence of asbestos aboard - WWII-era diesel auxiliaries still carried asbestos in some components (gaskets, electrical insulation, brake linings); it establishes only that nothing ship-specific is published. The wreck has never had an official material assessment; the 1985 scuttling preparation (Subsea Enterprises) predates routine hazmat-disclosure practice.
- Atlas source
- true
- Evidence ID
- ev-uss-yms-420-07