USS YMS-470

Evidence

17 evidence entries recorded; each entry has a stable permalink (#ev-1 … #ev-17).

1. [1]research packet 967-packet.md (4 sources cited) [other_primary]

   Finding type

   vessel_history

   Finding

   Identity packet verdict: USS PCS-1438 → **MISMATCH

   Verification

   verified

   Role

   correction

   Documentation level

   ship_specific

   Evidence ID

   uss-yms-470-pkt-967-packet-md

2. [2]Dictionary of American Naval Fighting Ships, Swan II (YMS-470) - live NHHC page [nhhc_danfs]

   Locator

   DANFS Swan II narrative and spec block

   Finding type

   vessel_history

   Finding

   DANFS (live NHHC page, 'Swan II (YMS-470)') documents: laid down 12 August 1943 by the Gibbs Gas Engine Co., at Jacksonville, Fla., as PCS-1438; redesignated YMS-470 on 27 September 1943; launched 5 April 1944; completed and commissioned on 14 October 1944. Operated along the U.S. east coast until March 1945; South Pacific, vicinity of New Caledonia and the New Hebrides until August; Okinawa and Japan for post-war minesweeping and occupation duty; returned to the U.S. mid-April 1946; decommissioned 1 June 1946 and placed in reserve at Stockton, Calif.; named Swan and redesignated AMS-37 while in reserve. Towed to the Bethlehem Pacific Coast Corp. yard at San Francisco and recommissioned 8 November 1950; trained minesweeper crews for the Far East for just over three years with Mine Squadron 5 on the west coast, flagship first of MinDiv 55 then MinDiv 51; January 1954 reassigned to MinDiv 45, Atlantic Fleet, homeported at the Minecraft Base, Charleston, S.C.; a year later joined MinDiv 44 as school ship at the Mine Warfare School, Yorktown, Va.; redesignated MSC(O)-37 on 1 August 1955 (date conflicts with NavSource - see gaps); reported to the Florida Group, Atlantic Reserve Fleet; decommissioned 6 October 1955, berthed at Green Cove Springs, Fla.; struck from the Navy list 1 November 1959; sold to the General Motors Defense Research Laboratories at Santa Barbara for conversion to a research vessel. Spec block: dp. 320 (full); l. 136'0"; b. 24'6"; dr. 6'1"; s. 12 k.; cpl. 33; a. 1 3", 2 20mm.; cl. YMS-1.

   Verification

   verified

   Role

   supporting

   Documentation level

   ship_specific

   Accessed

   2026-10-04

   Study period

   1943-1959

   Population

   Gibbs Gas Engine construction trades (1943-44); U.S. Navy crews (1944-46, 1950-55); Bethlehem Pacific Coast yard trades (1950 recommissioning)

   Limitations

   Ship-specific official history only; contains no asbestos, material-content, work-package, or exposure information. DANFS gives no date for the Swan naming/AMS-37 reclassification and dates MSC(O)-37 to 1 August 1955 where NavSource gives 7 February 1955 (see gaps).

   Atlas source

   true

   Evidence ID

   ev-uss-yms-470-01

3. [3]NavSource Online, Mine Warfare Vessel Photo Archive, Swan (MSC[O] 37) ex-YMS-470 ex-PCS-1438 (live page verified 2026-10-04) [other_primary]

   Locator

   Header chronology, specifications block, commanding-officer list, and photo captions

   Finding type

   vessel_history

   Finding

   NavSource's live timeline (Swan (MSC[O] 37) ex-Swan (AMS 37) ex-YMS-470 ex-PCS-1438; call sign November-Quebec-Zulu-Delta) records: laid down 12 August 1943 as PCS-1438 by Gibbs Gas Engine Co., Jacksonville, FL; reclassified Auxiliary Motor Minesweeper YMS-470 on 27 September 1943; launched 5 April 1944; completed and commissioned USS YMS-470, 14 October 1944; decommissioned 1 June 1946 at Stockton, CA and laid up at San Diego, CA (with a note that the Naval Vessel Register of 1 January 1949 lists a plan for decommissioning and placing in reserve as February 1947); named Swan and reclassified Motor Minesweeper AMS-37, 18 February 1947; recommissioned 8 November 1950; reclassified Coastal Minesweeper (Old) MSC(O)-37, 7 February 1955 (conflicts with DANFS 1 August 1955 - see gaps); decommissioned 6 October 1955 at Green Cove Springs, FL; struck from the Navy Register 1 November 1959. Post-Navy chain: sold in 1959 to the General Motors Defense Research Laboratories at Santa Barbara, CA; acquired in 1960 by the General Motors Corp. of Goleta, CA; acquired around 1980 by Windjammer Cruises of Honolulu, HI for use as a yacht and renamed Royal Taipan; acquired in the early 1990s by Sause Brothers Ocean Towing Co., Inc. of Portland, OR; sank a short time later and was out of documentation in 1996. Page carries a commanding-officer list (LT Emanuel Duke, USNR, commissioning CO 14 Oct 1944 - Mar 1945; LTJG Stanley S. Rapport, USNR, two tours; LTJG John T. Knight, USNR; LTJG Eugene E. Boynton, USNR; LT George A. Cashman, USNR from 8 Nov 1950; LT William Reutter Steers; LTJG Ronald Stewart Burton; LCDR Charles Henry Garner, dates unknown) and a crew-service caption: Chief Motor Machinist Mate Murdock Rozell Hewett was a member of the commissioning crew of USS YMS-470 on 14 October 1944 and served aboard until 31 May 1945. Specification block: 270 t., 136', 24'6", 8' draft, 15 kts, complement 32, one 3"/50 dual-purpose mount, two 20mm mounts, two depth-charge projectors; two 880 bhp GM 8-268A diesels, Snow and Knobstedt single reduction gear, two shafts.

   Verification

   partial

   Role

   supporting

   Documentation level

   ship_specific

   Accessed

   2026-10-04

   Study period

   1943-1996

   Population

   Gibbs Gas Engine construction trades (1943-44); commissioning crew incl. named member CMM Murdock Rozell Hewett; U.S. Navy crews (1944-46, 1950-55); post-Navy merchant/research crews (1959-1990s)

   Limitations

   NavSource is a live secondary photo-archive compilation, not an official registry; milestone dates generally track DANFS/NVR but the MSC(O)-37 redesignation date (7 February 1955) conflicts with DANFS (1 August 1955) and the spec block differs from DANFS on displacement, draft, speed, and complement (see gaps). Contains no asbestos, survey, abatement, product, or exposure evidence.

   Atlas source

   true

   Evidence ID

   ev-uss-yms-470-02

4. [4]DANFS Swan II timeline ('laid down ... as PCS-1438; redesignated YMS-470 on 27 September 1943; ... completed and commissioned on 14 October 1944'), corroborated by NavSource; read with the supplied Trill fact-QA correction (crew signs 960-977, 2026-09-29) [nhhc_danfs]

   Locator

   DANFS Swan II narrative first paragraph; NavSource header chronology

   Finding type

   vessel_history

   Finding

   CORRECTION: PCS-1438 was a pre-commissioning contract designation only. The hull was laid down 12 August 1943 as PCS-1438 and redesignated YMS-470 on 27 September 1943 - before her 5 April 1944 launch and 14 October 1944 commissioning. She was commissioned as USS YMS-470 and never served under the PCS-1438 designation.

   Verification

   verified

   Role

   correction

   Documentation level

   ship_specific

   Accessed

   2026-10-04

   Study period

   1943-1944

   Limitations

   Corrects designation framing only - the same redesignation sequence appears in the DANFS narrative itself. Establishes no asbestos fact.

   Atlas source

   true

   Evidence ID

   ev-uss-yms-470-03

5. [5]Naval History and Heritage Command, Navy Department Library, 'United States Pacific Fleet Organization, 1 May 1945' (live page verified 2026-10-04) [nhhc_danfs]

   Locator

   MINECRAFT, PACIFIC FLEET section, YMS 470 row

   Finding type

   vessel_history

   Finding

   The Navy Department Library's transcription of United States Pacific Fleet organization as of 1 May 1945 lists YMS 470 in the MINECRAFT, PACIFIC FLEET section under Commander Minecraft, Pacific Fleet (R. Adm. A. Sharp), with commanding officer Lt. (jg) S. S. Rapport (USNR) - consistent with the NavSource command roster (LTJG Stanley S. Rapport, March-June 1945 tour).

   Verification

   verified

   Role

   supporting

   Documentation level

   ship_specific

   Accessed

   2026-10-04

   Study period

   1945-05-01

   Population

   YMS-470 crew under Lt.(jg) S. S. Rapport (May 1945)

   Limitations

   Establishes administrative assignment to Minecraft, Pacific Fleet and the commanding officer's name/rank on 1 May 1945 only. It does not locate the vessel geographically on that date, establish operations, or contain any asbestos, equipment, or exposure information.

   Atlas source

   true

   Evidence ID

   ev-uss-yms-470-04

6. [6]Naval History and Heritage Command photograph catalog, NH 84991 (live page verified 2026-10-04) [other_primary]

   Locator

   NH 84991 catalog page title and caption

   Finding type

   vessel_history

   Finding

   The NHHC photograph catalog identifies NH 84991 as 'USS YMS-470 (later: SWAN, AMS-37)', caption: 'In San Francisco Bay, circa 1945.'

   Verification

   verified

   Role

   supporting

   Documentation level

   ship_specific

   Accessed

   2026-10-04

   Study period

   circa 1945

   Limitations

   Official catalog description establishes the photograph's identity, location (San Francisco Bay), and approximate date (circa 1945) only. It does not establish construction details, equipment, asbestos, individual exposure, or causation.

   Atlas source

   true

   Evidence ID

   ev-uss-yms-470-05

7. [7]National Archives, Special List #44, by Ship Numbers, entry YMS-470 [other_primary]

   Locator

   PDF table entry: 'YMS-470 10/14/1944 6/30/1945'

   Finding type

   historical_record

   Finding

   NARA's Special List #44, by Ship Numbers, indexes deck-log coverage for YMS-470 from 14 October 1944 (commissioning day) through 30 June 1945 - establishing the existence and indexed span of deck-log records for the hull.

   Verification

   verified

   Role

   supporting

   Documentation level

   ship_specific

   Accessed

   2026-10-04

   Study period

   1944-10-14 to 1945-06-30 (indexed log span)

   Limitations

   Finding aid only: shows the indexed coverage dates of deck logs. It does not establish events on either endpoint, does not cover the 1946 Pacific return, the 1950-55 recommissioned era, or the post-Navy period, and contains no asbestos information.

   Atlas source

   true

   Evidence ID

   ev-uss-yms-470-06

8. [8]National Archives catalog, NAID 193179543, 'YMS-470, 10/14/44-7/3/46' (live page verified 2026-10-04) [other_primary]

   Locator

   Catalog file-unit page; parent series NAID 594996 (RG 24)

   Finding type

   historical_record

   Finding

   NARA holds and has digitized the WWII-era muster rolls for YMS-470 covering 14 October 1944 - 3 July 1946: file unit NAID 193179543, 59 scanned images (Ancestry partnership digitization), in the parent series 'Muster Rolls of U.S. Navy Ships, Stations, and Other Naval Activities' (Record Group 24).

   Verification

   verified

   Role

   archival_lead

   Documentation level

   ship_specific

   Accessed

   2026-10-04

   Study period

   1944-1946

   Population

   YMS-470 enlisted complement, Oct 1944 - Jul 1946 (roster source)

   Limitations

   Archival lead: digitized muster rolls establish crew names/rates by quarter for the WWII era - a personnel record, not a materials or asbestos record. Individual page contents were not transcribed for this record.

   Atlas source

   true

   Evidence ID

   ev-uss-yms-470-07

9. [9]National Archives catalog, NAID 99922923, 'Activity Number 0204 0037 - SWAN (YMS-470 / AMS-37 / MSCO-37) - 1952' (live page verified 2026-10-04) [other_primary]

   Locator

   Catalog file-unit page; microfilm series Navy_Muster_Rolls_post1949, USNMR_0268

   Finding type

   historical_record

   Finding

   NARA holds and has digitized the post-1949 muster roll 'Activity Number 0204 0037 - SWAN (YMS-470 / AMS-37 / MSCO-37) - 1952': file unit NAID 99922923, 83 scanned images from microfilm series USNMR_0268 (Fold3 digitization), cataloged explicitly under all three of this hull's designations. The 1952 sheets list crew by name, rate, and service number (e.g., Haxton, Donald J, SA; Smith, Leroy A, FN) - a Korea-era-crew roster source for the recommissioned ship.

   Verification

   verified

   Role

   archival_lead

   Documentation level

   ship_specific

   Accessed

   2026-10-04

   Study period

   1952

   Population

   USS Swan (AMS-37) crew, 1952 (roster source)

   Limitations

   Archival lead: a personnel roster, not a materials or asbestos record. Covers 1952 only; muster rolls for the remaining recommissioned years (1950-51, 1953-55) were not individually verified in this pass.

   Atlas source

   true

   Evidence ID

   ev-uss-yms-470-08

10. [10]NOAA Ocean Exploration, Okeanos Explorer ROV Dive Summary EX-16-08 Dive 02 (2016-12-04), 'Engineering Dive Site 3, South of Oahu' (live PDF retrieved 2026-10-04) [other_primary]

    Locator

    Dive summary 'Description of the Dive' section; name 'Royal Taipan' visible on stern in representative photos

    Finding type

    vessel_history

    Finding

    NOAA Ocean Exploration documentation establishes this hull's present disposition: Okeanos Explorer cruise EX-16-08, ROV Dive 2 (Deep Discoverer + Seirios, engineering dive site south of Oahu, December 2016) investigated a multibeam sonar target and identified the wooden motor vessel Royal Taipan out of Seattle on the bottom with a starboard list, ~41 m x 8 m by scanning sonar - dimensions consistent with the 136 ft YMS-1 hull. The dive team's identification research ties Royal Taipan to this vessel: commissioned as the auxiliary minesweeper USS Swan in 1944, in military service until 1959, purchased by General Motors Defense Research Laboratories and converted to a research vessel, operated by Windjammer Cruises in the 1980s-90s, last registered in Portland, Oregon, documentation ending 1996. The wreck's bridge equipment was removed, an open trunk penetrates the deck into the engine spaces, and a tow bridle on the bow confirms the vessel was stripped and towed to deep water and scuttled; the wooden hull shows substantial worm damage.

    Verification

    verified

    Role

    supporting

    Documentation level

    ship_specific

    Accessed

    2026-10-04

    Study period

    2016-12 (survey); scuttling window c.1990s

    Population

    None aboard at sinking; salvage/stripping crews pre-scuttling (dates undocumented)

    Limitations

    Federal wreck-survey record. The NOAA summary compresses the ship's naming history ('commissioned as ... USS Swan in 1944' - she was commissioned as YMS-470 and named Swan in 1947), but the stern name and the stated ownership chain identify this hull. The wreck position is redacted in the public document. No hazardous-material or asbestos assessment was performed; stripping/scuttling noted only.

    Atlas source

    true

    Evidence ID

    ev-uss-yms-470-09

11. [11]Cal State ScholarWorks reprint (marine-science journal article on borderland midwater fishes), UCSB/NSF grant acknowledgment: 'GB-2867 to the University of California, Santa Barbara, for charter of the General Motors Research Vessel Swan' (PDF retrieved live 2026-10-04) [other_primary]

    Locator

    Acknowledgments/methods section, p. 185 of the reprint

    Finding type

    vessel_history

    Finding

    A contemporaneous oceanographic publication documents the research-vessel career: the University of California, Santa Barbara deep-sea sampling program chartered 'the General Motors Research Vessel Swan' beginning in 1964 for discrete-depth plankton sampling in the Santa Barbara and Santa Cruz basins - corroborating the DANFS-recorded sale to General Motors Defense Research Laboratories for conversion to a research vessel.

    Verification

    verified

    Role

    supporting

    Documentation level

    ship_specific

    Accessed

    2026-10-04

    Study period

    1964 (program initiation; publication c.1966-70)

    Population

    R/V Swan operating crew and UCSB science parties (1964 onward, per this source)

    Limitations

    Establishes the vessel's post-Navy research employment in 1964+ under the name Swan. Contains no information on conversion work, material condition, or asbestos; the journal context is midwater-trawl ecology.

    Atlas source

    true

    Evidence ID

    ev-uss-yms-470-10

12. [12]ShipbuildingHistory, 'Yard Minesweepers YMS BYMS' production table (YMS-470 row) and 'Gibbs Gas Engine, Aerojet-General, Jacksonville Shipyards' yard page (both live 2026-10-04) [other_primary]

    Locator

    ym.htm YMS-470 table row; shipyards/small/gibbs.htm yard history

    Finding type

    vessel_history

    Finding

    ShipbuildingHistory (Tim Colton's shipbuilding reference) lists the production-table row 'YMS 470 | Gibbs Gas Engine | Jacksonville FL | 136 | 320 | 14-Oct-44 | Reclassified as Swan (AMS 37)' in the yard minesweeper table, and the companion Gibbs yard page records the builder's history: Gibbs Gas Engine Works, founded 1911, prolific builder of gas engines and small wooden and steel vessels in both World Wars; renamed Gibbs Corporation after WWII; sold to Aerojet-General Shipyards Corporation in 1964, then merged into Jacksonville Shipyards (1969, Fruehauf), with all three yards closed in 1992.

    Verification

    partial

    Role

    supporting

    Documentation level

    ship_specific

    Accessed

    2026-10-04

    Study period

    1943-1944 (build); yard history 1911-1992

    Population

    Gibbs Gas Engine wartime workforce (Jacksonville FL)

    Limitations

    Reputable secondary compilation (Colton), not a primary registry. Corroborates builder and delivery date; contains no asbestos information. The successor Jacksonville Shipyards entity has its own litigation history - not attributed to the wartime Gibbs yard or this hull.

    Atlas source

    true

    Evidence ID

    ev-uss-yms-470-11

13. [13]Era inference built on: NavSource YMS-1-class specification block and YMS-470 page (two GM 8-268A diesels, wooden hull class design); ShipbuildingHistory YMS/BYMS production narrative (561 wooden-hulled sweepers, 35 boatyards); GAO HRD-80-2 Navy-wide asbestos-era context (see ev-uss-yms-470-13) [other_primary]

    Locator

    NavSource YMS-1 class page specification block; shipbuildinghistory.com/smallships/ym.htm

    Finding type

    asbestos_application

    Finding

    A wooden-hulled diesel motor minesweeper of the YMS-1 class (built at one of 35 small yacht yards, 1942-45) carries the era-standard small-vessel asbestos applications rather than the steam-plant pathway: engine and exhaust thermal insulation, machinery gaskets and valve packing, electrical insulation in switchboards/panels, and brake linings on the sweep-winch and windlass. Her two GM 8-268A diesel engines drove shafts through a Snow and Knobstedt single reduction gear - no boilers, no steam lines, no turbine lagging. Hull construction was wood (non-magnetic service requirement).

    Verification

    inferred

    Role

    supporting

    Documentation level

    class_or_era

    Accessed

    2026-10-04

    Study period

    1943-1959

    Population

    Gibbs construction trades (1943-44); engine-room crews (1944-46, 1950-55); Bethlehem-Pacific recommissioning trades (1950); post-Navy conversion/salvage crews (1959-60, c.1990s)

    Limitations

    Class/era inference only - no hull-specific insulation survey, material list, or work package was located for YMS-470. Names era-standard applications, not confirmed installed materials; no quantity and no manufacturer attribution for this hull. A wooden diesel sweeper's asbestos inventory was materially lighter than a steam combatant's.

    Atlas source

    true

    Evidence ID

    ev-uss-yms-470-12

14. [14]U.S. Government Accountability Office, Navy Efforts To Protect Workers From Asbestos Exposure, HRD-80-2 (1979) [gao]

    Locator

    GAO product record HRD-80-2; direct product and PDF requests returned HTTP 403 during this pass

    Finding type

    gov_survey

    Finding

    GAO's 1979 report Navy Efforts To Protect Workers From Asbestos Exposure is Navy-wide historical context for asbestos use and worker-protection efforts; it is retained only as class/era context for a Navy vessel constructed in 1943-44 and in service through 1955.

    Verification

    partial

    Role

    context

    Documentation level

    class_or_era

    Accessed

    2026-10-04

    Study period

    1979 report; vessel service 1944-1955

    Population

    Navy asbestos program and workers (program-level context)

    Limitations

    The report was not retrievable live because GAO returned HTTP 403, so no detailed report proposition is attributed here. Navy-wide context cannot establish asbestos installation, product identity, quantity, condition, exposure, or causation aboard this hull.

    Atlas source

    true

    Evidence ID

    ev-uss-yms-470-13

15. [15]Identity disambiguation: mesothelioma.com minesweepers list displays 'USS Swan AM-34' (Lapwing class), not AMS-37; DANFS Swan entries distinguish Swan I (AM-34/AVP-7 era hull) and Swan II (YMS-470) [other_primary]

    Locator

    mesothelioma.com/asbestos-exposure/jobsites/ships/minesweepers/ ('USS Swan AM-34 Lapwing' row); DANFS Swan II header numbering

    Finding type

    historical_record

    Finding

    CORRECTION: asbestos-marketing ship lists that carry a 'USS Swan' entry refer to USS Swan (AM-34), the Lapwing-class minesweeper commissioned 1919 and transferred to the Maritime Commission in 1946 - a different, earlier hull. This vessel (YMS-470/AMS-37) is not the Swan in those lists; no authoritative source places asbestos documentation on either hull by name.

    Verification

    verified

    Role

    correction

    Documentation level

    ship_specific

    Accessed

    2026-10-04

    Study period

    2026-10-04 (collision documented)

    Limitations

    Corrects a name-collision risk between two USS Swans (AM-34 vs this hull). The marketing list is a banned-class source cited here only to document the collision, not as evidence; neither hull has a qualifying asbestos record in the sources searched.

    Atlas source

    true

    Evidence ID

    ev-uss-yms-470-14

16. [16]Research result for this batch; see search ledger and access gaps [other_primary]

    Locator

    Searches documented in search_ledger

    Finding type

    asbestos_application

    Finding

    No ship-specific asbestos survey, abatement record, hazmat disclosure, product identification, or museum/scrapping material record was located in the sources reviewed for this batch. Ship-specific asbestos documentation is unknown.

    Verification

    partial

    Role

    negative_finding

    Documentation level

    ship_specific

    Accessed

    2026-10-04

    Study period

    2026-10-04

    Limitations

    A bounded search result, not proof that records do not exist. NARA deck logs (indexed span ends 30 June 1945), muster rolls, and any Gibbs work packages were not reviewed at page/box level; whether they contain material specifications or asbestos information is unknown.

    Atlas source

    true

    Evidence ID

    ev-uss-yms-470-15

17. [17]CourtListener authenticated API v4 helper sweep (cl-auth-search.py), 2026-10-04 [other_primary]

    Locator

    search_ledger rows sl-uss-yms-470-08 through sl-uss-yms-470-11

    Finding type

    litigation_documented

    Finding

    No qualifying ship-specific asbestos litigation was located in this pass. Of the four mandatory authenticated CourtListener base searches, three completed: 'YMS-470' opinions (type=o, limit 20) returned count 53 - all hits were OCR-noise token collisions in unrelated criminal and commercial opinions, no qualifying case; 'YMS-470' dockets (type=r, limit 20) returned count 4,775 - raw token noise (immigration file numbers, dollar amounts), no qualifying case; 'USS Swan' opinions (type=o, limit 20) returned count 11 - all name collisions (e.g., United States v. Swan, a 1996 NMCCA court-martial; the maritime Douglass v. Nippon Yusen series), no qualifying case. The 'USS Swan' docket query was repeatedly declined by the authenticated helper's fleet-wide pacing gate; that is an access gap, not a zero-result finding.

    Verification

    partial

    Role

    negative_finding

    Documentation level

    ship_specific

    Accessed

    2026-10-04

    Study period

    2026-10-04

    Limitations

    Three completed base searches surface only collisions, not asbestos cases - but they do not prove no litigation exists; coverage is limited to the opinion and RECAP docket indexes under the exact strings searched. One of four base queries remained blocked by the fleet pacing gate at research time. No asbestos-qualified variants were run: the completed hull-number queries returned only non-case token noise (nothing resembling a qualifying case within the first page), so a variant could not have isolated anything the base query missed.

    Atlas source

    true

    Evidence ID

    ev-uss-yms-470-16