USS Constant (AM-427)

Evidence

12 evidence entries recorded; each entry has a stable permalink (#ev-1 … #ev-12).

1. [1]DANFS, 'Constant II (AM-427)' - official NHHC entry (published 30 Jun 2015), verified verbatim from Wayback capture 2025-01-20 (live history.navy.mil page returns 404 this session - standing link rot, same as BATCH-01/1135/1339); verbatim mirror transcription at hazegray.org/danfs/mine/am427.htm via Wayback capture 2024-06-18 [nhhc_danfs]

   Locator

   DANFS 'Constant II (AM-427)' entry, specifications block + service narrative (Wayback capture 20250120194301 of history.navy.mil/.../constant-ii.html; mirror Wayback 20240618214243 of hazegray.org/danfs/mine/am427.htm)

   Finding type

   vessel_history

   Finding

   Official DANFS record for this hull: spec block 'AM-427: dp. 620; l. 172'; b. 36'; dr. 10'; s. 15 k.; cpl. 74; a. 1 40mm.; cl. Agile.' 'The second Constant (AM-427) was launched 14 February 1953 by Fulton Shipyard, Antioch, Calif.; sponsored by Mrs. D. A. Webster; commissioned 8 September 1954, Lieutenant Commander R. M. Weymer in command; and reported to the Pacific Fleet.' Reclassified MSO-427 on 7 February 1955. West coast operations until clearing Long Beach 4 January 1956 for Pearl Harbor and Yokosuka (arriving 4 February): amphibious exercises at Iwo Jima, cable repairs, minesweeping and local operations from Sasebo to 28 March; training exercises with Republic of China naval forces based on Kaohsiung, Taiwan (2 April - 19 May); returned via Yokosuka to Long Beach, arriving 15 June. After overhaul and west coast operations, sailed from Long Beach 2 June 1958 for Sasebo; minesweeping off Okinawa 3 July - 30 August; stood by at Taiwan 2 September - 27 October during the Quemoy Crisis; called at Hong Kong; cleared Yokosuka 12 December for Long Beach, arriving 6 January 1959. Local operations from Long Beach through the remainder of 1959 and first half of 1960; sailed 31 August for Far East duty, where she remained into 1961.

   Verification

   verified

   Role

   supporting

   Documentation level

   ship_specific

   Accessed

   2026-09-22

   Study period

   1953-1961 (DANFS narrative coverage)

   Population

   Fulton Shipyard construction trades (Antioch, 1951-54); commissioned crew (DANFS complement 74), 1954-1992

   Limitations

   DANFS documents identity, builder, dates, and service narrative - not materials or asbestos content. No laid-down date is given (NVR supplies 16 August 1951 keel). The published entry's narrative ends in 1961 - it does not cover the 1960s-70s Vietnam-era deployments, the 1970s rehabilitation, the 1980s San Diego reserve-era service, the 1992 decommissioning, or the 1999-2001 disposal - those rest on NVR, NavSource, and secondary compilations (see ev-02/03/05/06). Live NHHC URL 404s; the 2025-01-20 Wayback capture of the official page is cited and the hazegray mirror transcription agrees verbatim.

   Atlas source

   true

   Evidence ID

   ev-uss-constant-am427-01

2. [2]Naval Vessel Register (NAVSEA), ship detail page for CONSTANT (MSO 427) ex-AM 427 - official inventory record (live nvr.navy.mil detail page renders only its navigation shell this session; cited via Wayback capture 2024-08-09) [marad_nrc]

   Locator

   NVR SHIPSDETAIL_MSO_427 (Wayback capture 20240809075607) - vessel status block, milestone dates, physical characteristics block

   Finding type

   vessel_history

   Finding

   Official NVR record for this hull: 'CONSTANT (MSO 427) (ex - AM 427) MINESWEEPER,OCEAN'; Class: MSO 422; UIC 07957. Milestones: award 27 January 1951; keel 16 August 1951; launch 14 February 1952; delivery 7 September 1954; commission 8 September 1954; decommission 30 September 1992; stricken 9 March 1994; status 'Disposed of by Dismantling (Scrapping/Recycling)', date status changed 04/01/2001 (April 1, 2001 - matching the documented scrapping completion). Physical characteristics: overall length 173 ft; light displacement 746 tons; 'Hull Material: Wood hull, (except engines and equipment)'; propulsion type Diesel; 2 propellers. Custodian: 'SCHOOLS, ORGANIZATIONS AND PRIVATE ENTERPRISES' - the private-sale disposal path consistent with the documented Crowley Marine scrapping sale.

   Verification

   verified

   Role

   supporting

   Documentation level

   ship_specific

   Accessed

   2026-09-22

   Study period

   1951-2001

   Population

   Navy inventory/disposal administrative record; disposal custodian (private-enterprise scrapping path)

   Limitations

   Official NAVSEA inventory record - the strongest single source for this hull. Its launch year (14 February 1952) conflicts with DANFS/NavSource/Wikipedia (14 February 1953) - flagged in correction row ev-11, not silently merged. NVR gives no homeport, operational, or materials detail; it documents registry milestones and construction type only. Contains no asbestos information; 'wood hull' confirms the non-steel construction but establishes nothing about insulation materials aboard.

   Atlas source

   true

   Evidence ID

   ev-uss-constant-am427-02

3. [3]NavSource Online: Mine Warfare Vessel Photo Archive - Constant (MSO-427) ex-AM-427, file 11/02427 (page by Gary P. Priolo / Joseph M. Radigan / David Wright) [other_primary]

   Locator

   NavSource 11/02427 - chronology block, spec block, propulsion line, CO roster (24 COs), photo captions/credits

   Finding type

   vessel_history

   Finding

   NavSource per-hull record: 'Aggressive Class Minesweeper'; laid down 16 August 1951 at Fulton Shipyard, Antioch, CA; launched 14 February 1953; commissioned USS Constant (AM-427) 8 September 1954; 'Reclassified as an Ocean Minesweeper, MSO-427, 7 February 1955'; decommissioned 30 September 1992; 'Struck from the Navy Register 9 March 1994'; 'Sold for scrap to Crowley Marine, removal date 29 September 1999'; 'Scrapped 1 April 2001.' Spec block: 630 t light / 755 t full load; 172'; 35' beam; 10' draft; 14 kts; complement 80; armament as built one 40mm mount and two .50-cal. machine guns, final configuration bow gun replaced by one twin 20mm mount. Propulsion: 'Four Packard ID1700 diesel engines, two shafts, two controllable pitch propellers.' Commanding-officer roster of 24 runs LCDR Raymond Merritt Weimer (8 Sep 1954) through LCDR Leviticus A. Lewis (to 30 September 1992). Photo captions document: Golden Gate c.October 1957; leading sister ships c.1960 (DANFS-credited USN photo); Vancouver BC 9 August 1965 and c.1987; 'c. April 1967 Off the coast of Vietnam' (taken from USS Caliente AO-53); Campbell Shipyard, San Diego between September 1987 and January 1988; Naval Base San Diego 1 July 1988 (USN photo DN-ST-89-09594); and 'c. 1999 At Mare Island Naval Shipyard being stripped of useful equipment prior to scrapping.' Call sign November-Delta-Alpha-Delta.

   Verification

   partial

   Role

   supporting

   Documentation level

   ship_specific

   Accessed

   2026-09-22

   Study period

   1951-2001

   Population

   Fulton Shipyard trades (1951-54); crew (74-80) 1954-1992; Campbell Shipyard workers (San Diego, 1987-88); stripping/scrapping workforce 1999-2001

   Limitations

   Specialist secondary compilation - detailed but non-official. Its complement (80) conflicts with DANFS's 74, its beam (35') with DANFS's 36', its speed (14 kts) with DANFS's 15 k, and its launch year (1953) with NVR's 1952 - flagged in ev-11, not silently merged. The c.1999 Mare Island caption places the hull at the former naval shipyard site during stripping - Mare Island NSY closed in 1996, so the stripping was a post-closure private operation at the site; single-source caption, not corroborated. Contains no asbestos information; supports no asbestos claim.

   Atlas source

   true

   Evidence ID

   ev-uss-constant-am427-03

4. [4]Shipbuilding History (Tim Colton compilation), 'Fulton Shipyard' Antioch CA yard table - Constant (AM 427) row + sister Conflict row + yard history header [other_primary]

   Locator

   shipbuildinghistory.com/shipyards/small/fulton.htm - Constant (AM 427) row, Conflict (AM 426) row, AMc/APc blocks, yard-history header

   Finding type

   vessel_history

   Finding

   Yard-table row for this hull: 'Constant (AM 427) | US Navy | Minesweeper | 780 | 8-Sep-54 | Later MSO 427, scrapped 2001'; adjacent sister row 'Conflict (AM 426) | US Navy | Minesweeper | 780 | 23-Mar-54 | Later MSO 426, scrapped 1973' - the two Aggressive-series hulls Fulton built. Yard history header: Fulton Shipyard was started in 1924 by Frank Fulton and Angeline Fulton Fredericks on a San Joaquin River site first developed as a shipyard in 1918 by Jarvis Bros.; the yard sat at the foot of Fulton Shipyard Road in downtown Antioch and closed in 1999. The table also carries the yard's WWII coastal-minesweeper block (AMc-86 through AMc-91) and APc-23-series transports.

   Verification

   verified

   Role

   supporting

   Documentation level

   ship_specific

   Accessed

   2026-09-22

   Study period

   1924-1999 (yard history); 1951-2001 (this hull's rows)

   Population

   Fulton Shipyard workforce (Antioch, CA, 1951-54)

   Limitations

   Compiler's yard table, secondary - corroborates builder, type, delivery (8-Sep-54 = commissioning date), and scrapping year (2001). Its '780' displacement conflicts with DANFS's 620 / NavSource's 630 lt - 755 fl / NVR's 746 light - flagged in ev-11. A yard table does not carry keel/launch dates or hull numbers. Contains no asbestos information; supports no asbestos claim.

   Atlas source

   true

   Evidence ID

   ev-uss-constant-am427-04

5. [5]Combat Fleets of the World (naval almanac transcript, jwilliamcupp.name mirror) - MSO 427 Constant line + Agile/Aggressive class table + MSO modernization notes [other_primary]

   Locator

   CombFlt.htm - MSO 427 CONSTANT row; 'AGILE Class, 421' + 'AGGRESSIVE Class, 422-427...' class table; MSO modernization paragraph

   Finding type

   vessel_history

   Finding

   Almanac line for this hull: 'MSO 427 CONSTANT - Fulton SY - 16AUG51 - 14FEB52 - 8SEP54 - 30SEP92 decomm; 1APR01 disposed.' The 14FEB52 launch year agrees with the official NVR record (14 February 1952) against DANFS/NavSource's 1953 - flagged in ev-11. Class table carries 'AGILE Class, 421' as a single hull and 'AGGRESSIVE Class, 422-427, 432-449, 455-474, 488-496' - placing this hull in the Aggressive block (427 is the last hull of the 422-427 group). Modernization notes: the 1968 plan to re-engine Agile/Aggressive/Acme-class MSOs with Waukesha diesels and SQQ-14 minehunting sonar was partly cancelled in 1970; MSO-427 is listed among the survivors that 'retained Packard lD1700 diesels, totaling 2,280 hp' while receiving 'very thorough rehabilitations during early to mid-1970s, receiving semi-enclosed bridges, and an enlarged superstructures abaft the bridge, SQQ-14 minehunting sonars, new communications gear, and upgraded accommodations.'

   Verification

   partial

   Role

   supporting

   Documentation level

   ship_specific

   Accessed

   2026-09-22

   Study period

   1951-2001

   Population

   1970s rehabilitation yard workforce (yard unnamed); crew 1970s-1992

   Limitations

   Secondary almanac transcript - supplies the 1970s rehabilitation scope (bridge/superstructure/sonar/comms/accommodations) that no other located source details; rehabilitation work of that scope on a 1950s hull is the classic insulation-disturbance context, but no asbestos scope is stated by the source. Its launch year (1952) agrees with NVR against DANFS - discrepancy carried open in ev-11. Contains no asbestos information; supports no asbestos claim.

   Atlas source

   true

   Evidence ID

   ev-uss-constant-am427-05

6. [6]Vietnam-era service documentation - NavSource photo caption (c. April 1967 off Vietnam, taken from USS Caliente AO-53); USS Mansfield (DD-728) deck-log transcription at ussmansfield.com; unofficial VA-ships compilation (E. Ball) citing MACV/NavForV Monthly Historical Summary July 1966 (DTIC ADA954001) [other_primary]

   Locator

   navsource.net/archives/11/02427.htm photo captions; ussmansfield.com/logmap/ '3 October 1966 ... 0851 USS Constant MSO-427'; scribd.com/doc/180764851 (unofficial Vietnam ship list); apps.dtic.mil/sti/tr/pdf/ADA954001.pdf (403 this session)

   Finding type

   vessel_history

   Finding

   Documented Vietnam-era operations beyond the DANFS narrative cutoff (1961): (a) NavSource photo 'c. April 1967 Off the coast of Vietnam - photo taken from USS Caliente (AO 53)'; (b) the USS Mansfield deck-log transcription records '0851 USS Constant MSO-427 Stbd' in the 3 October 1966 underway-replenishment sequence during Mansfield's Vietnam deployment, alongside USS Energy MSO-436 and fleet units; (c) an unofficial Vietnam ships compilation records 'USS Constant MSO-427 Coastal Patrol unit ref MACV Monthly Summary July 1966 pg 14' - referencing the U.S. Naval Forces Vietnam monthly historical summary (DTIC accession ADA954001, retrieval blocked this session); (d) secondary deployment lists (hullnumber.com) record WestPac/Vietnam windows including 1964-65, 1968-69, and 1970-72.

   Verification

   partial

   Role

   supporting

   Documentation level

   ship_specific

   Accessed

   2026-09-22

   Study period

   1964-1972 (documented Vietnam-era windows)

   Population

   Crew aboard during 1960s-70s WestPac/Vietnam deployments (complement ~74-80)

   Limitations

   Establishes the hull operated in the Vietnam theater (coastal patrol/Market Time-type MSO operations) - it is operational documentation, not a materials or asbestos record. Items (a) and (b) are photo-caption and deck-log-transcription level; (c) is an unofficial compilation citing a primary source not itself retrieved (DTIC returns 403 to automated fetch); (d) is an unreviewed secondary list. The hull does not appear in the VA herbicide-exposure ships list in the copies checked - offshore/coastal operations, not the inland-waterway category that list certifies.

   Atlas source

   true

   Evidence ID

   ev-uss-constant-am427-06

7. [7]Consolidated era/design inference - documented construction and machinery (NVR hull material 'Wood hull, (except engines and equipment)'; NavSource class index: 1950s MSO program 'built primarily of wood, with bronze and stainless (non-magnetic) steel fittings'; four Packard ID1700 diesels, two shafts, two CPPs per NavSource spec block and Combat Fleets class table) + documented builder and construction era (DANFS; NVR award 27 Jan 1951; Colton Fulton table) [other_primary]

   Locator

   NVR MSO-427 physical-characteristics block ('Wood hull'); NavSource 11/02idx class header + 11/02427 propulsion line; Combat Fleets class table; DANFS AM-427 entry

   Finding type

   asbestos_application

   Finding

   Era/design inference: this hull is a 1951-54-built wooden-hulled non-magnetic ocean minesweeper with a diesel direct-drive plant (four Packard ID1700 diesels, two shafts, two controllable-pitch propellers) - no steel hull to insulate, no boilers, no steam distribution. Its insulation load was materially lighter than a steam combatant's and lighter even than a steel-hulled diesel minesweeper's. Era-typical asbestos applications for a 1950s naval vessel of this type: exhaust-system and muffler lagging on the diesel plant and generators; machinery gaskets and packing; electrical-cable insulation; accommodation and galley joiner materials; deck coverings/floor tile; winch and windlass brake linings. Exposure-relevant populations if any material was present: Fulton Shipyard construction trades (Antioch, 1951-54); the commissioned crew (~74-80) across 1954-1992; yard workers during overhauls and the documented 1987-88 Campbell Shipyard availability; the early-to-mid-1970s rehabilitation workforce (bridge/superstructure rebuild documented per Combat Fleets); and the 1999-2001 stripping/scrapping workforce.

   Verification

   inferred

   Role

   supporting

   Documentation level

   class_or_era

   Accessed

   2026-09-22

   Study period

   1951-2001

   Population

   Fulton trades (1951-54); crew 1954-1992; yard workers (overhauls, 1970s rehabilitation, 1987-88 Campbell Shipyard); scrapping workforce 1999-2001

   Limitations

   Inference from documented design, machinery type, and construction era - NOT a hull materials record. No survey, specification, or material schedule naming AM-427/MSO-427 was located; establishes no asbestos content, quantity, location, condition, individual exposure, or causation. The wooden hull and diesel (non-steam) plant make even era-level inference weaker than for steel or steam vessels of the same era.

   Atlas source

   true

   Evidence ID

   ev-uss-constant-am427-07

8. [8]GAO HRD-80-2, 'Navy Efforts To Protect Workers From Asbestos Exposure' (1979-80); and T.J. Bigley (Navy) letter to GAO, 5 Jan 1979, as quoted in 'The Asbestos Health Hazards Compensation Act,' Journal of Legislation (Notre Dame) 10(1) [gao]

   Locator

   GAO HRD-80-2 product/PDF (gao.gov/assets/hrd-80-2.pdf); Notre Dame J. Legislation 10(1), 'The Asbestos Health Hazards Compensation Act' (scholarship.law.nd.edu/jleg/vol10/iss1/3) quoting Bigley letter of 5 Jan 1979

   Finding type

   gov_survey

   Finding

   Program-level documentation of the asbestos window this hull's entire career falls inside: GAO HRD-80-2 records that the Navy's product specifications for thermal insulation were changed in 1973 to specify asbestos-free materials, but asbestos materials already purchased were still installed - 'some ships were delivered with asbestos insulation as late as May 1978'; the Navy's elimination policy issued October 1975. A Navy letter to GAO dated 5 January 1979 (T.J. Bigley to Robert F. Hughes, quoted in the Notre Dame Journal of Legislation) states: 'all ships presently in service contain some quantity of asbestos.' Constant was built 1951-54 and in commission 1954-1992 - built entirely within the pre-1973 as-built asbestos era and serving through the 1979 all-ships statement's window.

   Verification

   verified

   Role

   context

   Documentation level

   class_or_era

   Accessed

   2026-09-22

   Study period

   1973-1979 policy window documented; hull era 1951-2001

   Population

   Navy personnel and shipyard workers, service-wide (era context)

   Limitations

   Program/era-level documentation; neither source names this vessel, class, or builder. GAO's fieldwork concerned shipyard workers (Long Beach, Norfolk). The 'all ships ... contain some quantity of asbestos' statement is quoted from a primary letter via a law-review source - the letter itself was not retrieved. gao.gov returns HTTP 403 to automated fetch (standing, same as BATCH-01); the PDF text was confirmed via search-snippet extraction, not full-text pull. Establishes nothing about this hull's materials, condition, or any individual exposure - and for a wooden-hulled diesel ship the proposition applies with materially reduced scope.

   Atlas source

   true

   Evidence ID

   ev-uss-constant-am427-08

9. [9]Wineland v. Air & Liquid Sys. Corp., 539 F. Supp. 3d 1149 (W.D. Wash. 2021), Cause No. C19-0793RSL (Judge Lasnik) - order granting Crane Co.'s motion for summary judgment (Dkt. #304); companion orders grant other defendants' MSJs [court_record]

   Locator

   539 F. Supp. 3d 1149 (W.D. Wash. 2021); docket 2:19-cv-00793-RSL (W.D. Wash.); order PDF mirrors brownsims.com (Dkts. 302, 304, 309, 313, 427, 550)

   Finding type

   litigation_documented

   Finding

   Class-adjacent asbestos litigation exists for this vessel type: plaintiffs alleged decedent John Dale Wineland was exposed to asbestos-containing products while working engine rooms aboard Navy ships 1963-1984, including Agile/Aggressive-series ocean minesweepers USS Dynamic (MSO-432, 1963-66), USS Pledge (MSO-492, 1966-67), USS Loyalty (MSO-457, 1970-72), and USS Esteem (MSO-438, 1978-80) - sisters of this hull in the same wooden-hulled, diesel-engined MSO design family. The opinions record machinery-space work on 'diesel engines, pumps, air compressors, and valves' and litigation-stage product-identification evidence (e.g., Alfa Laval purifiers and DeLaval lube-oil pumps in the aft engine rooms of Dynamic, Loyalty, Esteem, Pledge). Disposition per litigation-stage discipline: the located rulings are summary-judgment-stage defense wins (Crane Co. MSJ granted, 539 F. Supp. 3d 1149; companion MSJs granted) - merits-level negatives for that plaintiff, not exposure findings; the vessel/product allegations are pleadings and motion-stage record assertions, not adjudicated facts. No appellate disposition was located.

   Verification

   verified

   Role

   context

   Documentation level

   class_or_era

   Accessed

   2026-09-22

   Study period

   2019-2021 litigation; exposure period alleged 1963-1980

   Population

   MSO engine-room sailors (class context), 1963-1980

   Limitations

   Context only - the cited case does not name or involve USS Constant/AM-427/MSO-427, and its sister-ship allegations never reached a merits finding on exposure. It establishes only that asbestos claims were litigated at the pleading/SJ stage for the same MSO type and diesel machinery spaces. Does not establish or defeat any exposure claim or legal eligibility for this hull. CourtListener API was quota-blocked at session time; the reporter citation and docket are verified via vLex metadata and the order PDFs mirrored at brownsims.com (defense firm); a CourtListener opinion URL was not resolved.

   Atlas source

   true

   Evidence ID

   ev-uss-constant-am427-09

10. [10]Batch-1340 search ledger (this record): DANFS via Wayback capture of the NHHC page + hazegray mirror; NVR MSO-427 detail via Wayback; NavSource 11/02427 + 11/02idx class index; Shipbuilding History Fulton yard table; Combat Fleets transcript; ussmansfield.com deck-log transcription; NARA catalog API; VA BVA index; site-scoped and general web litigation queries for AM-427/MSO-427/USS Constant; CourtListener API v4 (throttled) [other_primary]

    Locator

    search_ledger rows sl-uss-constant-am427-01 through sl-uss-constant-am427-15

    Finding type

    historical_record

    Finding

    No qualifying ship-specific asbestos record located for USS Constant / AM-427 / MSO-427: no asbestos survey, abatement contract, hazmat disclosure, preservation record, court finding, VA decision, or docketed asbestos case naming this hull was found in the public sources searched (see search_ledger). CourtListener's authenticated API returned HTTP 429 (shared 2,800/day quota exhausted by prior batch work; reset ~7.7h) - no unauthenticated queries were run, and the opinion/RECAP sweeps are logged as blocked. Site-scoped web search of courtlistener.com and general-web litigation queries surfaced no vessel association; the only federal administrative hit - a 2017 BVA asbestos decision - names USS Constellation (CV-64), a name collision excluded on review. Non-authoritative marketing rosters carry the name in generic ship tables (mesothelioma.com minesweepers table: 'USS Constant | AM-427 | Aggressive | 9/8/1954 | Scrapped, 2001'; mesotheliomahelp.org, freeasbestostesting.com, and navyshipexposure.com minesweeper lists name the hull; navyshipexposure's per-hull page presents a class-pattern 'equipment manifest' assembled from sister ships) - excluded per source rules; they carry no hull-specific evidence.

    Verification

    verified

    Role

    negative_finding

    Documentation level

    ship_specific

    Accessed

    2026-09-22

    Study period

    2026-09-22

    Limitations

    Absence of a located public record does not prove absence of asbestos aboard - a 1951-54 naval vessel is era-consistent with asbestos-containing materials even accounting for its wooden hull and lighter diesel insulation load. The hull was scrapped in the U.S. in 2001, so no present-day survey pathway exists. The CourtListener sweep is incomplete (quota) - residual risk that a differently-phrased hull reference exists is logged as a gap. Does not establish presence or absence; does not establish or defeat any exposure claim or legal eligibility.

    Atlas source

    true

    Evidence ID

    ev-uss-constant-am427-10

11. [11]Source-discrepancy resolution - official NHHC DANFS text (Wayback 2025-01-20) vs NVR MSO-427 record (Wayback 2024-08-09) vs NavSource 11/02427 vs Colton Fulton yard table vs Combat Fleets transcript vs historycentral/Wikipedia derivatives [other_primary]

    Locator

    Wayback 20250120194301 NHHC DANFS 'Constant II' entry; Wayback 20240809075607 NVR MSO-427; navsource.net 11/02427; shipbuildinghistory.com/shipyards/small/fulton.htm; jwilliamcupp.name/Story/CombFlt.htm; historycentral.com/navy/Minelayer/Constant2.html; en.wikipedia.org/wiki/USS_Constant_(AM-427)

    Finding type

    historical_record

    Finding

    Source discrepancies logged, not silently merged: (a) Launch year - official DANFS and NavSource read 14 February 1953; the official NVR record and the Combat Fleets almanac both read 14 February 1952. Two official sources conflict; DANFS (1953) is carried in the launched field and the conflict is flagged - keel 16 Aug 1951 makes either plausible, though 1952 (six-month build) is the more typical interval for a 172-ft wooden MSO. (b) Complement - DANFS 'cpl. 74' vs NavSource '80' vs Wikipedia '6 officers, 74 enlisted' - unresolved; DANFS carried. (c) Displacement - DANFS '620' vs NavSource '630 lt / 755 fl' vs NVR '746' light vs Colton '780' vs Wikipedia '775' - conventions differ (light/full), not reconciled. (d) Beam - DANFS '36'' vs NavSource '35'' - DANFS carried. (e) Length - DANFS/NavSource '172'' vs NVR '173 ft' overall - not reconciled. (f) Speed - DANFS '15 k.' vs NavSource/Combat Fleets '14 kts' - DANFS carried. (g) Class grouping - DANFS spec block 'cl. Agile' vs NVR 'Class: MSO 422' vs NavSource 'Aggressive Class' header vs Combat Fleets 'AGILE Class, 421' + 'AGGRESSIVE Class, 422-427...' - recorded as Agile/Aggressive series, Aggressive block; AM-427 is the last hull of the 422-427 group. (h) First CO - DANFS 'Lieutenant Commander R. M. Weymer' vs NavSource 'LCDR Raymond Merritt Weimer' - spelling conflict, unresolved. (i) Stricken date - NVR/NavSource 9 March 1994; a Wikipedia-language edition prints 9 May 1994 - March carried per official NVR. (j) historycentral.com's DANFS transcription misprints 'sailed from Long Beach 2 June 1955' where the official text and hazegray mirror read 2 June 1958 - mirror transcription error flagged, official text carried.

    Verification

    partial

    Role

    correction

    Documentation level

    ship_specific

    Accessed

    2026-09-22

    Study period

    1951-2001

    Limitations

    Resolves publication-level discrepancies among the official DANFS text, the official NVR record, and secondary compilations, adopting the better-supported values and flagging the rest. The 1953-vs-1952 launch-year conflict is a genuine official-source split (DANFS vs NVR), not a transcription error - both years are carried in their respective rows. No asbestos content in any of these sources.

    Atlas source

    true

    Evidence ID

    ev-uss-constant-am427-11

12. [12]Archival leads - NARA catalog (verified via catalog API this session): RG 24 'Logbooks of U.S. Navy Ships and Stations' file units for Constant (MSO-427), ~19 digitized monthly logbooks spanning February 1956 - November 1977 (e.g., NAIDs 213005256 Feb 1956, 214338619 Sep 1960, 175446656/175446854 Sep/Dec 1967, 631844381 Mar 1972, 649736590-649736912 Jan-Jun 1974, 665672789 Mar 1977, 665673519 Nov 1977); RG 19 Bureau of Ships 'Photographs of U.S. and Foreign Naval Vessels' - 12 digitized photo items for 'AM-427 Constant' (NAID series 6932606-6932629, Box 1551, local IDs 19-NN-AM-427 Constant-*); NARA RG 19 hull files / Entry P-11 minesweeper GIBs / S39-S103 engineering drawings per the asbestos guided-topic page; MACV/NavForV monthly summaries at DTIC; Navy disposal file for the 1999 Crowley Marine sale [other_primary]

    Locator

    catalog.archives.gov search 'Constant (MSO-427)' - RG 24 logbook file units (NAIDs 213005256, 213006402, 217588490, 217589698, 217589766, 217589834, 217590176, 214338619, 175446656, 175446854, 634577834, 634577964, 631844381, 649736590, 649736656, 649736846, 649736912, 665671659, 665671959, 665672789, 665673519); RG 19 photo items NAIDs 6932606-6932629; archives.gov/research/military/navy guided-topics; DTIC ADA954001

    Finding type

    historical_record

    Finding

    Archival leads: (a) NARA's digitized deck-log coverage for this hull is CONFIRMED via the catalog API - at least 19 monthly file units in RG 24 'Logbooks of U.S. Navy Ships and Stations' spanning Feb 1956 through Nov 1977, each with scanned images (65-127+ objects per unit) - the documentary base for the Vietnam-era windows, overhauls, and the 1970s rehabilitation; (b) 12 digitized Bureau of Ships photographs of 'AM-427 Constant' exist in RG 19 (Still Pictures, College Park) - construction/early-service photography is the closest existing thing to a material record for this hull; (c) NARA RG 19 BuShips records per the asbestos guided-topic page - hull-designation correspondence ('AM427'/'MSO427'), class correspondence under the namesake ('AM421 Class' - Agile), builder contract files ('QM/Fulton Shipyard'), Entry P-11 'Minesweeper and Minelayer General Information Books' (Item S-68), and hull-number-arranged Ship Engineering Drawings (S39 Insulation and Lagging, S48 Piping, S103 Booklets of General Plans) - the plausible home of hull-level material schedules; (d) the U.S. Naval Forces Vietnam Monthly Historical Summary for July 1966 (DTIC ADA954001) - the cited source for the 'coastal patrol unit' reference, retrieval blocked this session (HTTP 403); (e) Campbell Shipyard, San Diego records for the documented Sep 1987-Jan 1988 availability; (f) the Navy/MARAD disposal file for the 1999 sale to Crowley Marine (removal 29 Sep 1999) and the 1999-2001 stripping/scrapping chain.

    Verification

    unverified

    Role

    archival_lead

    Documentation level

    context_only

    Accessed

    2026-09-22

    Study period

    1951-2001 records

    Limitations

    Record-group mapping plus confirmed catalog hits - the deck-log and photo items exist digitized, but no page-level review was performed (research-room/reproduction scope; no spend authorized). Deck logs are operations records, not materials documentation; the BuShips design file is the best candidate for a material schedule. Existence of asbestos-specific documents for AM-427/MSO-427 is unknown until surveyed. Nothing in this row is an asbestos finding.

    Atlas source

    true

    Evidence ID

    ev-uss-constant-am427-12