USS YMS-21

Evidence

25 evidence entries recorded; each entry has a stable permalink (#ev-1 … #ev-25).

1. [1]research packet 1039-packet.md [other_primary]

   Finding type

   vessel_history

   Finding

   Identity packet verdict: VERIFIED

   Verification

   verified

   Role

   supporting

   Documentation level

   ship_specific

   Evidence ID

   uss-yms-21-yms21-pkt-1039-packet-md

2. [2]NavSource Online: Mine Warfare Vessel Photo Archive, YMS-21 - construction milestones, specifications, loss and striking (live page verified HTTP 200, 2026-10-04) [other_primary]

   Locator

   NavSource 11/19021.htm header block, YMS-1 Class chronology, and specifications block

   Finding type

   vessel_history

   Finding

   Documented for this hull: laid down 28 June 1941 by the Greenport Basin and Construction Co., Long Island, NY; launched 25 November 1941; completed 18 April 1942; 'Struck a mine 1 September 1944 and sank, at 43°06'N., 05°54'E., off Toulon, France'; struck from the Naval Register 16 September 1944. 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, two depth-charge projectors; propulsion two 880bhp General Motors 8-268A diesel engines, Snow and Knobstedt single-reduction gear, two shafts. Call sign Nan-Able-Zebra-Yoke. Photographed underway off the Norfolk Navy Yard 2 June 1942 (NHHC photo NH 91616). Page states explicitly: 'There is no DANFS history available for YMS-21.'

   Verification

   verified

   Role

   context

   Documentation level

   ship_specific

   Accessed

   2026-10-04

   Study period

   1941-1944

   Population

   Greenport Basin construction trades (1941-42); US Navy crew (1942-44)

   Limitations

   NavSource is a volunteer secondary compilation, not a primary registry - its milestone dates are corroborated here by NARA primary records (muster rolls, war diaries, action report, combat interview) and by DANFS for the rescue-ship entry. 'Off Toulon' is the page's framing; the commanding officer's recorded account places the sinking inside Toulon Harbor in 44 feet of water (see ev-16). Contains no asbestos or material content.

   Atlas source

   true

   Evidence ID

   ev-uss-yms-21-yms21-01

3. [3]NavSource Online: Auxiliary Motor Minesweeper (YMS) / British Motor Minesweeper (BYMS) Index - class description and characteristics (live page verified HTTP 200, 2026-10-04) [other_primary]

   Locator

   NavSource 11/19idx.htm class narrative and characteristics table

   Finding type

   vessel_history

   Finding

   Class context for this hull: 'The wood-hulled YMS proved to be one of the U.S. Navy's more durable and versatile types'; 481 ships of the type built 'at 35 yacht yards, rather than larger shipyards; 12 on the East Coast; 19 on the West Coast, and four in the Great Lakes.' YMS-1 through YMS-134 (this hull's block) carried two stacks. Originally rated as service craft; used in WWII for inshore sweeping to prepare amphibious assaults; survivors reclassified AMS and named 1947; MSC(O) 1955.

   Verification

   verified

   Role

   context

   Documentation level

   class_or_era

   Accessed

   2026-10-04

   Study period

   1941-1969

   Population

   YMS-1-class crews and builder-yard trades (class context)

   Limitations

   Class-level description, not a hull record. The class index prints total construction as both '561' (narrative, all yards/types incl. BYMS) and '481 ships of this type'; the 481 figure matches the US YMS series. No asbestos or material content.

   Atlas source

   true

   Evidence ID

   ev-uss-yms-21-yms21-02

4. [4]National Archives, Special List 44: List of Logbooks of U.S. Navy Ships, Stations, and Miscellaneous Units, 1801-1947 - ship-number index (official NARA-hosted PDF, verified live 2026-10-04) [other_primary]

   Locator

   sl-44-ship-number.pdf page 116, row 'YMS-21 4/23/1942 7/31/1944' (pdftotext -layout, page 116)

   Finding type

   historical_record

   Finding

   Special List 44 (ship-number index, PDF page 116) lists US Navy logbooks for YMS-21 covering 4/23/1942 - 7/31/1944. The coverage window opens on the muster-documented crew-receipt/commissioning date (23 April 1942) and closes five weeks before the hull's loss (1 September 1944) - the August-September 1944 deck logs went down with the ship or were not preserved in this series. Logbooks of this era are held in RG 24 (Bureau of Naval Personnel), Entry 118 at Archives II, College Park.

   Verification

   verified

   Role

   archival_lead

   Documentation level

   ship_specific

   Accessed

   2026-10-04

   Study period

   1942-1944 (coverage); 1978 (publication)

   Population

   US Navy crew (1942-44) - logbook subjects

   Limitations

   Finding-aid inventory entry only: it documents that logbooks exist and their coverage window - these are log-coverage dates, NOT commissioning or decommissioning dates, and the row asserts nothing about log content. The indexed deck-log pages themselves are not digitized in this series and were not examined; the daily deck-log form survives separately in the November 1943 handwritten war diary (ev-05).

   Atlas source

   true

   Evidence ID

   ev-uss-yms-21-yms21-03

5. [5]NARA Catalog, 'YMS-21, 4/23/42-9/11/44' (NAID 192868249) - digitized US Navy muster rolls, 140 images (Fold3 partnership scan of microfilm) [other_primary]

   Locator

   NAID 192868249 digital objects, images 32863_254978-00004/00006 (April 1942 Reports of Changes incl. commissioning report), -00002 (June 1942 forwarding sheet, Little Creek VA), -00127/-00129 (30 Jun 1944 roll and recapitulation), -00134/-00135 (September 1944 Report of Changes, post-sinking dispositions)

   Finding type

   historical_record

   Finding

   The hull's muster rolls are digitized and were sampled directly (first reports and final reports of a 140-image set): the first Report of Changes covers 'the month ending 23rd day of April, 1942' and lists the commissioning crew received aboard 23-30 April 1942 from Receiving Ship New York (names, service numbers, ratings - e.g., BM, MM, EM, QM, SM, Y, SC ratings of a small diesel minesweeper); the June 1942 forwarding sheet is signed by Ensign J. Wolfe, Jr., USNR, Executive Officer, approved by 'A.A. CAMPBELL, Lieut., USNR, Commanding,' forwarded from Little Creek, Virginia. The Muster Roll of the Crew for the quarter ending 30 June 1944 lists the crew by name; its recapitulation sheet records 'Brought forward from last quarter, 28 ... Total on board during the quarter, 35 ... Remaining on board and carried forward, 27. Operating allowance, 28.' The September 1944 Report of Changes documents survivor disposition after the sinking: named men transferred 2 September 1944 to 'USS ARMY Hospital Ship (ACADIA) for treatment' and on 11 September 1944 to 'Rec. Sta. Oran, Algeria FFT for further transfer to the U.S.A., Auth: 6thPhib/P16-3 ... of Sept. 9, 1944.'

   Verification

   verified

   Role

   supporting

   Documentation level

   ship_specific

   Accessed

   2026-10-04

   Study period

   1942-04-23 to 1944-09-11

   Population

   YMS-21 crew - commissioning crew received 23-30 Apr 1942; 27 enlisted carried forward at 30 Jun 1944 plus officers; post-sinking enlisted dispositions (USS Acadia; Rec Sta Oran)

   Limitations

   Population documentation, not an exposure record: the muster names and rates the crew but contains no asbestos, material, or health information. Officers are rostered separately and were not individually read this session. The September 1944 Report of Changes lists enlisted post-loss dispositions only; no 'died' entries appear in the pages read - the two men lost (per ev-16) may be recorded on a page not sampled, or may be officers outside the enlisted roll.

   Atlas source

   true

   Evidence ID

   ev-uss-yms-21-yms21-04

6. [6]NARA Catalog, 'USS YMS-21 - War Diary, 11/1-30/43' (NAID 136033040, 30 images; WWII War Diaries microfilm; micro serial 61060, file A12-1) [other_primary]

   Locator

   NAID 136033040 digital objects (30 handwritten NAVPERS-136 daily sheets)

   Finding type

   vessel_history

   Finding

   Ship's war diary for November 1943, filed as 30 pages of handwritten NAVPERS-136 (Part II) 'Operational Remarks (War Diary)' daily deck-log sheets for USS YMS-21, approved/signed by the commanding officer (T.S. Rothwell signature block). The December 1943 typed diary establishes she was then 'at Palermo, Sicily attached as before to Commander Escort Sweeper Group under Commander Amphibious Forces Eighth Fleet,' and the November sheets are the daily position/operations record of that duty.

   Verification

   partial

   Role

   supporting

   Documentation level

   ship_specific

   Accessed

   2026-10-04

   Study period

   1943-11-01 to 1943-11-30

   Population

   YMS-21 crew under CO Lt. T.S. Rothwell, USNR

   Limitations

   Primary ship record in handwritten deck-log form - the handwriting defeats reliable OCR, so this row records the document's existence, form, and coverage rather than day-level detail. Contains no asbestos or material content visible in the form structure. This is the only surviving daily deck log digitized for the hull (the typed monthly narratives ev-06 through ev-14 are the readable operational record).

   Atlas source

   true

   Evidence ID

   ev-uss-yms-21-yms21-05

7. [7]NARA Catalog, 'USS YMS-21 - War Diary, 12/1-31/43' (NAID 78243385, 2 images; WWII War Diaries microfilm roll A_0766; micro serial 62365) [other_primary]

   Locator

   NAID 78243385 digital objects, roll A_0766 images 0194-0195 (dry-dock entries on img 0194-0195)

   Finding type

   vessel_history

   Finding

   Ship's typed war diary, read via OCR: December 1943 at Palermo, Sicily, attached to Commander Escort Sweeper Group under Commander Amphibious Forces Eighth Fleet, temporary duty under COM NOB Palermo - near-daily alternating 'swept two channels into Palermo, magnetic and acoustic' with 'Maintenance, Rest and Recreation' alongside piers. 21 December: 'Entered dry-dock #2 Palermo and floated clear of water. Ship's force commenced cleaning bottom and base carpenters started repairs to keel, beading and other parts of hull.' 22-23 December: ship's force painted the bottom. 24 December: left dry dock, moored East mole while base force completed deck caulking. Signed 'T.S. Rothwell.'

   Verification

   verified

   Role

   supporting

   Documentation level

   ship_specific

   Accessed

   2026-10-04

   Study period

   1943-12-01 to 1943-12-31

   Population

   YMS-21 crew; Palermo dry-dock/base carpenters (Dec 1943)

   Limitations

   Primary ship record read via OCR of Fold3/NARA scans - all claims legible in context. The dry-dock entry documents a maintenance event (keel/beading/hull repairs, bottom cleaning and painting, deck caulking), not the materials used. No asbestos or material content.

   Atlas source

   true

   Evidence ID

   ev-uss-yms-21-yms21-06

8. [8]NARA Catalog, 'USS YMS-21 - War Diary, 1/1-31/44' (NAID 78284353, 2 images; WWII War Diaries microfilm roll A_0802; micro serial 64105) [other_primary]

   Locator

   NAID 78284353 digital objects, roll A_0802 images 0367-0368

   Finding type

   vessel_history

   Finding

   Ship's typed war diary, read via OCR: January 1944 - Palermo channel sweeps through 7 January, then 'Underway for Cagliari, Sardinia' 8 January, arriving 9 January and reporting to NOIC for sweeping assignment. Swept QBB 280 on 10, 12, 14 and 16 January (with YMS-24, then YMS-64); 19 January 'Underway as escort for S.S. Swift Arrow to convoy rendezvous'; 20, 27 and 28 January swept the approach channel to S. Antioco, Sardinia, magnetic type. Signed 'T.S. Rothwell.'

   Verification

   verified

   Role

   supporting

   Documentation level

   ship_specific

   Accessed

   2026-10-04

   Study period

   1944-01-01 to 1944-01-31

   Population

   YMS-21 crew; YMS-24/YMS-64 sweep partners

   Limitations

   Primary ship record read via OCR - all claims legible in context. No asbestos or material content.

   Atlas source

   true

   Evidence ID

   ev-uss-yms-21-yms21-07

9. [9]NARA Catalog, 'USS YMS-21 - War Diary, 2/1-29/44' (NAID 78327591, 2 images; WWII War Diaries microfilm roll A_0851; micro serial 66659) [other_primary]

   Locator

   NAID 78327591 digital objects, roll A_0851 images 0122-0123

   Finding type

   vessel_history

   Finding

   Ship's typed war diary, read via OCR: February 1944 - Cagliari sweeps of QBB 280 through 3 February; 4-5 February returned to Palermo and reported to Commander NOB for duty. Repairs and maintenance alongside Pier #3 Palermo 6-7 February; Palermo harbor sweeps (magnetic, acoustic, moored, 'O' type) through the month. 10 February: 'Acted as escort for Italian Submarine during exercises to test underwater listening gear in Palermo Gulf.' Signed 'T.S. Rothwell.'

   Verification

   verified

   Role

   supporting

   Documentation level

   ship_specific

   Accessed

   2026-10-04

   Study period

   1944-02-01 to 1944-02-29

   Population

   YMS-21 crew; Italian submarine exercise participants (Feb 1944)

   Limitations

   Primary ship record read via OCR - all claims legible in context. The 'repairs and maintenance alongside Pier #3' entry documents upkeep presence, not materials. No asbestos or material content.

   Atlas source

   true

   Evidence ID

   ev-uss-yms-21-yms21-08

10. [10]NARA Catalog, 'USS YMS-21 - War Diary, 3/1-31/44' (NAID 78358010, 1 image; WWII War Diaries microfilm roll A_0887; micro serial 68653) [other_primary]

    Locator

    NAID 78358010 digital object, roll A_0887 image 0019

    Finding type

    vessel_history

    Finding

    Ship's typed war diary, read via OCR: March 1944 - 1-5 March 'At Anzio Italy ... Temporary duty at Anzio beachhead under FOWIT ... swept anchorage and fire support areas both MA and moored type and patrolled as ordered during night. Numerous air raids undergone, bombs and torpedoes dropped and ships were shelled from the beach during daylight. No casualties sustained.' 5 March to Naples; 7-8 March Capri rest; 9-16 March 'Repair availability at NOB Palermo' under COMESWEGR orders 081529; 17-31 March temporary sweeping duty under NOB Palermo, rotating with other minesweeps (MA and moored type). Signed 'T.S. Rothwell.'

    Verification

    verified

    Role

    supporting

    Documentation level

    ship_specific

    Accessed

    2026-10-04

    Study period

    1944-03-01 to 1944-03-31

    Population

    YMS-21 crew; NOB Palermo repair trades (Mar 1944)

    Limitations

    Primary ship record read via OCR - all claims legible in context. The 'repair availability at NOB Palermo' entry documents a yard availability event, not materials used. No asbestos or material content.

    Atlas source

    true

    Evidence ID

    ev-uss-yms-21-yms21-09

11. [11]NARA Catalog, 'USS YMS-21 - War Diary, 4/1-30/44' (NAID 78423431, 1 image; WWII War Diaries microfilm roll A_0953; micro serial 72486) [other_primary]

    Locator

    NAID 78423431 digital object, roll A_0953 image 0689

    Finding type

    vessel_history

    Finding

    Ship's typed war diary, read via OCR: April 1944 - Palermo sweeps, then 3-14 April attached to U.S. Naval Detachment Cagliari, sweeping QBB 280 and QBB 318 (magnetic, acoustic, moored). 15-17 April to Naples and then Anzio. 18-30 April 'Sweeping Duty under Naval Officer in Charge, Anzio. On April 19, 1944 detonated magnetic and acoustic mine (as detailed in YMS-21 ltr, S81-1/A-4 of 19 April 1944 to Vice CNO.)' 23 April returned to Naples for repair of the Special Service generator. Signed 'T.S. Rothwell.'

    Verification

    verified

    Role

    supporting

    Documentation level

    ship_specific

    Accessed

    2026-10-04

    Study period

    1944-04-01 to 1944-04-30

    Population

    YMS-21 crew; Naples repair trades (Special Service generator, Apr 1944)

    Limitations

    Primary ship record read via OCR - all claims legible in context. The detonated-mine entry references a separate action letter (YMS-21 ltr S81-1/A-4, 19 Apr 1944) not located in the catalog this session - open archival lead. No asbestos or material content.

    Atlas source

    true

    Evidence ID

    ev-uss-yms-21-yms21-10

12. [12]NARA Catalog, 'USS YMS-21 - War Diary, 5/1-31/44' (NAID 78446288, 1 image; WWII War Diaries microfilm; micro serial 74191) [other_primary]

    Locator

    NAID 78446288 digital object

    Finding type

    vessel_history

    Finding

    Ship's typed war diary, read via OCR: May 1944 - 1-9 May at Anzio beachhead, 'swept assigned areas daily, Magnetic and acoustic and smoked anchorage at dusk. No mines swept.' 9-10 May Naples maintenance/upkeep; 11-13 May Capri rest; 13-14 May underway for Bizerte; 15-23 May 'Maintenance and repair availability at AATS, Bizerte'; 25-28 May training and instruction at Palermo; 29-31 May temporary duty at Naples. Signed 'T.S. Rothwell.'

    Verification

    verified

    Role

    supporting

    Documentation level

    ship_specific

    Accessed

    2026-10-04

    Study period

    1944-05-01 to 1944-05-31

    Population

    YMS-21 crew; AATS Bizerte repair trades (May 1944)

    Limitations

    Primary ship record read via OCR - all claims legible in context. The AATS Bizerte 'maintenance and repair availability' entry documents a yard availability event, not materials used. No asbestos or material content.

    Atlas source

    true

    Evidence ID

    ev-uss-yms-21-yms21-11

13. [13]NARA Catalog, 'USS YMS-21 - War Diary, 6/1-30/44' (NAID 78513352, 2 images; WWII War Diaries microfilm roll A_1042; micro serial 78596) [other_primary]

    Locator

    NAID 78513352 digital objects, roll A_1042 images 0382-0383

    Finding type

    vessel_history

    Finding

    Ship's typed war diary, read via OCR: June 1944 - Naples to Palermo 2-3 June; 4-8 June Palermo to Arzeu to Mers-el-Kebir, Algeria, 'preparing for operation Tarheel'; 10 June 'Underway for operation Tarheel under Commander Task Unit 81.2. Swept designated channel and then recovered gear and proceeded to designated anchorage. Swept designated anchorage and then recovered gear and proceeded to patrol area'; 11 June patrolled until released by CTU 81.2 'with a "well done"'; 14-18 June 'Repair availability at AATS, Bizerte, Tunisia'; 19 June to Cagliari for duty under NOIC; 27-30 June to Naples awaiting orders.

    Verification

    verified

    Role

    supporting

    Documentation level

    ship_specific

    Accessed

    2026-10-04

    Study period

    1944-06-01 to 1944-06-30

    Population

    YMS-21 crew; AATS Bizerte repair trades (Jun 1944); CTU 81.2 operation participants

    Limitations

    Primary ship record read via OCR - all claims legible in context. 'Operation Tarheel' is the diary's name for the 10-11 June Mers-el-Kebir-area sweep operation under CTU 81.2; its relation to later operations is not further documented here. The AATS Bizerte availability documents a yard event, not materials. No asbestos or material content.

    Atlas source

    true

    Evidence ID

    ev-uss-yms-21-yms21-12

14. [14]NARA Catalog, 'USS YMS-21 - War Diary, 7/1-31/44' (NAID 78551828, 2 images; WWII War Diaries microfilm roll A_1079; micro serial 80956) [other_primary]

    Locator

    NAID 78551828 digital objects, roll A_1079 images 0116-0117

    Finding type

    vessel_history

    Finding

    Ship's typed war diary, read via OCR: July 1944 - 1 July 'At Naples, Italy in dry-dock at Molo San Vincenzo, by order Commander Escort Sweeper Group for routine bottom work.' 2-4 July via Civitavecchia to Piombino; 5-14 July 'Swept daily in Piombino area both M&A and O type. Swept channels to Elba and to San Stefano and north toward Livorno.' 15-16 July back to Naples; night sweeping practice and practice invasion sweeps in the Gulf of Gaeta 17-27 July, including a 'new type of drag net sweep' with YMS-82 (23 July). 27 July 'Commenced sweeping Gulf of Gaeta near Formia de Gaeta. YMS 303 detonated two (2) magnetic mines, YMS-18 detonated one (1) magnetic mine and YMS-21 detonated one (1) magnetic mine this date. The last mine was reported to Vice Chief of Naval Operations by YMS-21 ltr S81-1/A-4 of 28 July 1944.' 30 July AM-118 detonated a magnetic mine south of Gaeta Bight; YMS-21 laid dan buoys. 31 July practice invasion 'Shamrock' in the Gulf of Gaeta - 'Swept in before invasion forces at Red beach and later patrolled.' Signed 'T.S. Rothwell.'

    Verification

    verified

    Role

    supporting

    Documentation level

    ship_specific

    Accessed

    2026-10-04

    Study period

    1944-07-01 to 1944-07-31

    Population

    YMS-21 crew; Naples dry-dock trades (1 Jul 1944); YMS-82/YMS-303/YMS-18/AM-118 sweep partners

    Limitations

    Primary ship record read via OCR - all claims legible in context. The Molo San Vincenzo dry-dock entry documents 'routine bottom work' - a maintenance event, not materials used. The 27 July mine detonation references a separate action letter (YMS-21 ltr S81-1/A-4, 28 Jul 1944) not located in the catalog this session - open archival lead. No asbestos or material content.

    Atlas source

    true

    Evidence ID

    ev-uss-yms-21-yms21-13

15. [15]NARA Catalog, 'USS YMS-21 - War Diary, 8/1-31/44' (NAID 78622010, 2 images; WWII War Diaries microfilm roll A_1133; micro serial 85498, dated 9/1/1944) [other_primary]

    Locator

    NAID 78622010 digital objects, roll A_1133 images 0561-0562

    Finding type

    vessel_history

    Finding

    Ship's typed war diary, read via OCR - her last: dated 1 September 1944 (the day she sank). August 1944 - upkeep at Naples 1-11 August; 12 August 'Underway from Naples harbor ... in convoy en route to invade Southern France as described in reference (b)' [YMS-24 action report of 22 August 1944]; 14 August through the Straits of Bonifacio; 15 August 'broke away from assault convoy, streamed port side oropesa gear and acoustic pipes and swept assault channel into Baie de Cavalaire ahead of invasion forces. Swept to within 900 yards of beach. Later swept anchorages, fire support and other areas in Baie de Cavalaire and Baie de Briande, Southern France ... Results negative.' 16-22 August routine sweeps Baie de Cavalaire; 23 August underway with other YMSs and AMs to Marseilles to sweep the approach channel, lying offshore Port de Bouc until recalled; 25-27 August routine sweeping Baie de Cavalaire; 28 August to Hyeres Bay, moored starboard side to YMS-18; 29-31 August 'Swept channels and anchorage in Bay of Toulon, magnetic and acoustic sweep. Results negative.' Signed 'T.S. Rothwell.'

    Verification

    verified

    Role

    supporting

    Documentation level

    ship_specific

    Accessed

    2026-10-04

    Study period

    1944-08-01 to 1944-08-31

    Population

    YMS-21 crew; Dragoon sweep unit (YMS-355, YMS-34, YMS-18, YMS-82, SC-979); Toulon-area task group

    Limitations

    Primary ship record read via OCR - all claims legible in context. The diary is dated 1 September 1944, the day of her loss - it was evidently completed before or around that date and covers operations through 31 August; the sinking itself is documented by ev-15 (action-report endorsement chain) and ev-16 (CO/XO recorded account). No asbestos or material content.

    Atlas source

    true

    Evidence ID

    ev-uss-yms-21-yms21-14

16. [16]NARA Catalog, 'USS YMS-21 - Rep of minesweeping ops in the invasion of Southern France, 8/15-17/44' (NAID 139972745, 8 images; WWII War Diaries microfilm; micro serial 116483) [other_primary]

    Locator

    NAID 139972745 digital objects, images 0195-0202 (report 0195-0199; endorsements 0200-0202)

    Finding type

    vessel_history

    Finding

    Ship's own action report for Operation Dragoon, dated 22 August 1944, read via OCR: 'Report of Amphibious Operations conducted against the enemy by U.S.S. YMS-21 in Southern France during the period 9 August 1944 to 17 August 1944.' Task: an oropesa/magnetic-acoustic sweep of the assault channel and boat lanes to within 1,000 yards of 'Red' beach centered three-quarters of a mile east of Cavalaire-sur-Mer, Baie de Cavalaire. Formation: YMS-355 guide on the channel centerline; YMS-21 and YMS-34 in port echelon with oropesa gear; YMS-18 and YMS-82 with magnetic-acoustic gear; SC-979 ahead with starboard oropesa. Sortie from Naples 1739B 12 August in convoy SM-1-B; YMS-21 in the inner screen; D-Day announced as 15 August, H-hour 0800; through Bonifacio Straits after daylight 14 August; released to Commander Alpha Task Force 1720B; 0530 15 August fell in astern of YMS-355 at battle stations, ~12 knots breakaway; 0559 streamed port oropesa gear (42-foot float pendant, 250 fathoms of sweep wire, one mechanical and five explosive cutters per FIP 204A); near-fouling by a battleship passing close ahead and two destroyers astern; naval and air bombardment to H-hour (P-47s diving, Havocs, Fortresses, Lightnings on top cover); went to within 900 yards of the center of Red Beach, turned to starboard, completed task one with negative results and no casualties; fired one round of three-inch at a wooded area on the beach at 0725 (area Roger 3); task two (Fire Support Area One) complete 0945; task three (boat lane to Green Beach with YMS-34 as guide and YMS-82) complete 1250; task four (area Roger 7, Baie de Briande; YMS-355/YMS-21/YMS-34 O-type, YMS-18/YMS-82 M&A) complete 1550 - all negative. She carried a special .625-inch rocket projector on the bow but had no cause to fire it. First endorsement (27 Aug, Commander Section Two, Task Unit 84.8.1): 'This vessel is to be commended for taking such excellent advantage of training beforehand to have everything ready, including the high morale of crew and officers for any eventuality.' Second endorsement 9 September 1944 (Mine Division Sixteen / Commander Task Unit 84.8.1, signed F. Wallis); third endorsement 18 September 1944 (Escort Sweeper Group, USS Barricade) - both issued after her loss.

    Verification

    verified

    Role

    supporting

    Documentation level

    ship_specific

    Accessed

    2026-10-04

    Study period

    1944-08-09 to 1944-09-18 (report and endorsement chain)

    Population

    YMS-21 crew; Red Sweep Unit, Task Unit 84.8.1 (YMS-355, YMS-34, YMS-18, YMS-82, SC-979); Task Force 84 under Com8thPhib

    Limitations

    Primary ship record read via OCR - all claims legible in context; minor OCR uncertainty on individual figures (fathoms, times) where noted by '~'. The report describes combat operations only - no asbestos, material, or maintenance content. The post-loss endorsements (9 and 18 Sept 1944) document the report's administrative chain, not the sinking.

    Atlas source

    true

    Evidence ID

    ev-uss-yms-21-yms21-15

17. [17]NARA Catalog, 'Rothwell, Lieutenant T. S.' (NAID 278493873) - RG 38 WWII combat interview recording transcript, NW 54487 / Film #288, 27 images + index (recorded 5 October 1944, Office of Naval Records and Library) [other_primary]

    Locator

    NAID 278493873 digital objects 2990147-24-13-0001 through -0027 (narrative pp. 1-9 and corrected copy; recording index/cover sheets -0024/-0025)

    Finding type

    historical_record

    Finding

    The ship's own recorded combat interview - 'Narrative by Lieutenant T. S. Rothwell, USNR, YMS 21 and Lt.(j.g.) G. A. Stark, USNR, Exec. ... Recorded 10-5-44 ... in the Office of Naval Records and Library' (NW 54487, Film #288; indexed 'Actions of YMS-21 at Sicily, Salerno, Anzio and Southern France'), read via OCR: Rothwell states YMS-21 'left the continental limits of the United States on 28 of April, 1943 and arrived in Algeria on the 25th of May, 1943,' then based at Oran and Bizerte; for the Sicily invasion (July 1943) she sailed in a preinvasion convoy of about six YMSs but rough seas prevented sweeping ahead of the assault forces - she carried out 'post assault sweeping assignments,' two weeks in southern Sicily, then swept the Palermo area when that city fell; for Salerno (September 1943) the YMSs 'swept in toward the beaches and numerous mines were cut that night and there was shelling from the beach but there were no casualties among our ships' - she was at North beach about ten days working mostly with the British; at Anzio (from about two weeks after the beachhead opened) the seas never subsided, 'we never could anchor,' there were heavy air raids, she 'picked up survivors of British ships which had sunk,' swept magnetic and acoustic mines 'dropped nightly by planes and E-boats,' and saw two-man torpedoes destroyed and captured. On the loss: after the beachheads were secured and Toulon had fallen, her task group was assigned to clear Toulon Bay and Toulon Harbor; 'We swept Toulon Bay for two days and on the third day were ordered into the harbor to sink floating mines ... by rifle fire, having been told that the area would be swept when we got there.' After boat minesweepers reported the area swept 'up to a certain buoy up ahead,' she proceeded, firing at the mines: 'At about 1600 on that day (the 1st of September), there was an underwater explosion under our stern and the whole ship was lifted up and of course immediately subsided back into the water and the stern was a mass of wreckage. There were about five men trapped in the wreckage. All hands were called to extricate the men and all but two were freed and are survivors.' Damage detail: yardarms broken, radio equipment thrown to the deck, salt-water lines carried away, electric wiring sparking; ships 200 yards away could not hear the explosion - 'it is thought that the mine was a small one.' Survivors were picked up by LCVPs converted into boat minesweepers 'slipping their minesweep gear and coming to our aid. The whole sinking took up, we should say, less than [hand-corrected:] 5 minutes and the ship finally sank in 44 feet of water in Toulon Harbor at about 1605 that day. All the survivors were taken to the U.S.S. PLANTER and from there by devious means have been returned to the States.' Stark adds Palermo air-raid detail: 'We had the MAYRANT there - F.D.R. Jr.'s ship was sunk [sic; damaged] off Palermo by these dive bombers,' towed into harbor by an AM; and at Salerno, YMS-15 shot down the German torpedo plane.

    Verification

    verified

    Role

    supporting

    Documentation level

    ship_specific

    Accessed

    2026-10-04

    Study period

    1943-04-28 to 1944-10-05

    Population

    YMS-21 crew - all hands at loss (about five trapped, all but two freed per CO); survivors to USS Planter (ACM-2); Lt. T.S. Rothwell USNR (CO) and Lt.(jg) G.A. Stark USNR (XO)

    Limitations

    Primary first-person account recorded five weeks after the loss, read via OCR of the declassified transcript (draft and corrected copy both scanned). Casualty wording quoted verbatim: 'all but two were freed and are survivors' - i.e., two men died trapped in the wreckage. Stark's 'sunk' for Mayrant is loose - USS Mayrant (DD-402) was damaged, not sunk (she survived the war); the index line crediting the tow 'by YMS-21' conflicts with the transcript's 'an AM towed the MAYRANT into the harbor' - transcript carried. Contains no asbestos or material content.

    Atlas source

    true

    Evidence ID

    ev-uss-yms-21-yms21-16

18. [18]DANFS, Planter (ACM-2) - verbatim transcription via HyperWar/ibiblio (live page verified HTTP 200, 2026-10-04) [nhhc_danfs]

    Locator

    HyperWar DANFS ACM-2 entry, service narrative paragraph 2 ('At Toulon, 1 September she rescued 31 survivors from YMS-21, sunk by a mine')

    Finding type

    historical_record

    Finding

    DANFS corroborates the rescue: the entry for USS Planter (ACM-2) - the converted Army mine planter supporting Dragoon minesweeping and buoy-laying - records: 'At Toulon, 1 September she rescued 31 survivors from YMS-21, sunk by a mine, then resumed her support activities.'

    Verification

    verified

    Role

    supporting

    Documentation level

    ship_specific

    Accessed

    2026-10-04

    Study period

    1944-09-01

    Population

    31 YMS-21 survivors rescued by USS Planter (ACM-2), 1 Sep 1944

    Limitations

    Establishes 31 survivors rescued at Toulon on 1 September 1944; combined with the commanding officer's 'all but two were freed' (ev-16), the aboard-at-loss count is 33 (2 lost + 31 survivors). DANFS names the mine-sunk cause of loss but does not give casualties among the trapped. Cited via the HyperWar verbatim transcription of DANFS. No asbestos or material content.

    Atlas source

    true

    Evidence ID

    ev-uss-yms-21-yms21-17

19. [19]US Navy WWII campaign/battle-star listing for YMS-21 - transcription attributed to Navy and Marine Corps Awards Manual NAVPERS 15,790 (Rev. 1953) (live page verified HTTP 200, 2026-10-04) [other_primary]

    Locator

    officialmilitaryribbons.com YMS 1-200 battle-star table, 'YMS 21' rows

    Finding type

    vessel_history

    Finding

    Campaign-credit transcription lists YMS-21 for four European-African-Middle Eastern operations: '9 Jul 43 - 15 Jul 43 | E2 | Sicilian occupation'; '9 Sep 43 - 21 Sep 43 | E3 | Salerno landings'; '25 Feb 44 - 1 Mar 44 | E4-1 | Anzio-Nettuno advanced landings'; and '15 Aug 44 - 1 Sep 44 | E7 | Invasion of Southern France' - the last window closing on her loss date. Each window is independently corroborated by the hull's own records (ev-05 through ev-16): Sicily service per the Rothwell interview, Salerno per the interview, Anzio per the March-May 1944 diaries, and Southern France per the August diary and action report.

    Verification

    partial

    Role

    context

    Documentation level

    ship_specific

    Accessed

    2026-10-04

    Study period

    1943-1944

    Population

    YMS-21 crew (award windows Jul 1943 - Sep 1944)

    Limitations

    Secondary transcription of NAVPERS 15,790 - not verified against the manual itself this session; the source site is a commercial ribbon vendor compiling official data. Award windows are ship-eligibility dates, not proof of individual crew entitlement or of presence on every day of the window. No asbestos content.

    Atlas source

    true

    Evidence ID

    ev-uss-yms-21-yms21-18

20. [20]uboat.net Allied Warships, USS YMS-21 (YMS-21) ship page (verified live HTTP 200, 2026-10-04) [other_primary]

    Locator

    uboat.net ship/9449 - specifications table and History line

    Finding type

    vessel_history

    Finding

    Secondary corroboration: uboat.net lists USS YMS-21 (YMS class minesweeper): ordered 1 April 1941; built by Greenport Basin and Construction Co. (Greenport, Long Island, New York); laid down 28 June 1941; launched 25 November 1941; 'Commissioned 18 Apr 1942'; lost 1 September 1944; loss position 43°06'N, 5°54'E; 'Mined and sunk off Toulon, France.' No commanders listed.

    Verification

    partial

    Role

    context

    Documentation level

    ship_specific

    Accessed

    2026-10-04

    Study period

    1941-1944

    Population

    YMS-21 crew

    Limitations

    Independent secondary compilation - the 'Commissioned 18 Apr 1942' line conflicts modestly with the muster/SL44 evidence that crew receipt and log coverage begin 23 April 1942 (NavSource prints only 'Completed 18 April 1942'); carried as the commissioning-date variant, logged in gaps. No asbestos content.

    Atlas source

    true

    Evidence ID

    ev-uss-yms-21-yms21-19

21. [21]Shipbuilding History (shipbuildinghistory.com / navalmarinearchive.com mirror), 'Greenport Basin & Construction Co., Greenport NY' build table (live page verified HTTP 200, 2026-10-04; shipbuildinghistory.njscuba.net mirror unreachable this session) [other_primary]

    Locator

    Greenport Basin build table, YMS-21 row (YMS-20/-31 block)

    Finding type

    vessel_history

    Finding

    Corroborating build-table row for the yard: 'YMS 21 | US Navy | Minesweeper | 278d | 136 | 18-Apr-42 | Mined off Toulon and lost 1944' - within a consecutive Greenport Basin block building YMS-20 through YMS-31, YMS-183/184 and BYMS-185ff, confirming the builder identity and the 18 April 1942 delivery/completion date.

    Verification

    partial

    Role

    context

    Documentation level

    ship_specific

    Accessed

    2026-10-04

    Study period

    1941-1944

    Population

    Greenport Basin construction trades (1941-42)

    Limitations

    Secondary shipbuilding-data compilation (Tim Colton's ShipbuildingHistory, via mirror) - corroborating-only, consistent with NavSource and uboat.net on builder and dates; '278d' displacement variant vs NavSource '270 t.' noted in gaps. No asbestos content.

    Atlas source

    true

    Evidence ID

    ev-uss-yms-21-yms21-20

22. [22]U.S. Naval Institute, Naval History Magazine (Oct. 2013, Vol. 27 No. 5), 'Risk vs. Reward Off the Italian Riviera' - YMS-21 in the mine-casualty list (content via search-result extraction; direct fetch blocked HTTP 403, 2026-10-04) [reputable_press]

    Locator

    USNI Naval History article, Toulon-area mine-casualty paragraph (search-result extraction; page 403 to automated fetch)

    Finding type

    vessel_history

    Finding

    Operational context corroboration: a USNI Naval History article on the Italian-Riviera mine campaign lists YMS-21 among the Dragoon-era mine losses in company with other units: 'Less fortunate were PT-555 on 24 August, YMS-21 on 1 September, a British LCM the next day, the small minesweeper YMS-23 on 26 September, the French tug Provencal on 4 September, and PT-311 on 18 November.'

    Verification

    partial

    Role

    context

    Documentation level

    ship_specific

    Accessed

    2026-10-04

    Study period

    1944

    Limitations

    Reputable-press corroboration of the loss date/context only; the magazine page blocks automated fetch (HTTP 403 to curl with browser UA, confirmed 2026-10-04), so the quotation is carried via verified search-result extraction - an access gap, not a dead source. Adds no fact beyond the primary record. No asbestos content.

    Atlas source

    true

    Evidence ID

    ev-uss-yms-21-yms21-21

23. [23]Era inference built on: NavSource YMS-21 spec block (GM 8-268A diesel pair, no steam plant); NavSource class index (wood-hulled, yacht-yard construction); NARA war diaries (maintenance events); GAO HRD-80-2 era documentation (ev-23) [other_primary]

    Locator

    NavSource 11/19021.htm spec block; NavSource 11/19idx.htm class narrative; NARA NAIDs 78243385, 78358010, 78446288, 78513352, 78551828 (dry-dock/availability/generator entries); GAO HRD-80-2

    Finding type

    asbestos_application

    Finding

    A 1941-42 wood-hulled diesel minesweeper sits inside the Navy's documented asbestos-use era, but the asbestos-relevant systems aboard a vessel of this type are limited compared with steam combatants: era-standard applications were thermal insulation and lagging around engine exhaust and machinery spaces, gaskets and valve packing in machinery and fuel/seawater systems, and electrical insulation/fireproofing. She carried no steam plant - the boiler/turbine lagging pathway of steam vessels does not apply. Her documented maintenance events (Dry Dock #2 Palermo 21-24 Dec 1943; repair availabilities at NOB Palermo Mar 1944 and AATS Bizerte May and Jun 1944; dry-dock at Molo San Vincenzo, Naples 1 Jul 1944; Special Service generator repair Apr 1944) are the kind of work that disturbs installed materials, noted as pathway context only.

    Verification

    inferred

    Role

    supporting

    Documentation level

    class_or_era

    Accessed

    2026-10-04

    Study period

    1941-1944

    Population

    Greenport Basin construction trades (1941-42); YMS-21 crew incl. engine-room ratings (MoMM/MM/EM) (1942-44); Palermo/Naples/Bizerte dry-dock and repair trades (1943-44)

    Limitations

    Class/era inference only - no hull-specific insulation survey, material list, or work package located for YMS-21, and her own war diaries/muster rolls/action report/interview name no materials. Names era-standard applications, not confirmed installed materials. No quantity, no manufacturer attribution. Wood hull reduces (does not eliminate) expected asbestos extent versus steel steamships; the hull now lies in 44 feet of water in Toulon Harbor.

    Atlas source

    true

    Evidence ID

    ev-uss-yms-21-yms21-22

24. [24]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, reconfirmed 2026-10-04)

    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 (1941-42) and service era (1942-44).

    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, reconfirmed 2026-10-04) - content via product-page description.

    Atlas source

    true

    Evidence ID

    ev-uss-yms-21-yms21-23

25. [25]Batch-8860 search ledger (this record): NARA SL44 PDF; NARA Catalog digitized muster rolls + 10 war diaries + Dragoon action report + Rothwell/Stark interview (all downloaded and OCR'd); NavSource ship page + class index; uboat.net; shipbuildinghistory mirror; NAVPERS 15,790 transcription; NHHC/DANFS (Planter via HyperWar; YMS-21 page absent); NVR; USNI (blocked); GAO (blocked); CourtListener (blocked - fleet-paced); secondary web litigation sweep [other_primary]

    Locator

    search_ledger rows sl-uss-yms-21-yms21-01 through -15

    Finding type

    historical_record

    Finding

    No qualifying ship-specific asbestos record located: no asbestos survey, abatement contract, hazmat disclosure, material list, or verified litigation naming USS YMS-21 was found in the public sources searched (see search_ledger). No DANFS entry exists for the hull (NavSource states this; NHHC candidate URLs 404). NVR carries no entry (pre-1987 disposal). The digitized primary records read directly for this record - the November 1943-August 1944 war diaries, the quarterly muster rolls, the Operation Dragoon action report, and the Rothwell/Stark recorded interview - contain operational, personnel, and loss detail but no asbestos, insulation, or hazmat content. CAVEAT: CourtListener could not be fully searched this session - base queries were blocked by the fleet-wide pacing limiter on four spaced attempts; logged as blocked in search_ledger, not as a negative result. Secondary web sweeps surfaced only the Wikipedia casualty line (corroborated by ev-16/ev-17) and law-firm marketing content asserting asbestos aboard WWII-era craft without primary sourcing - excluded by source policy.

    Verification

    partial

    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 litigation repository search is a genuine open gap (fleet-paced, not run). The undigitized RG 24 deck logs (SL44 coverage to 31 Jul 1944), Greenport Basin yard records, and the two YMS-21 action letters (S81-1/A-4 of 19 Apr and 28 Jul 1944) are unexamined leads. Does not establish or defeat any claim of exposure or legal eligibility.

    Atlas source

    true

    Evidence ID

    ev-uss-yms-21-yms21-24