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USS MONOB I (YAG 61) in September 1970.

USS MONOB I (YAG 61) in September 1970.
Click on this photograph for links to larger images of this class.

Class: MONOB I (YAG 61)
Design: Navy YW 83
Displacement (tons): 1,390 full
Dimensions (feet): 173.8' oa x 33.2' x 15.75'
Armament: none
Accommodations: 20 civilian
Speed (kts.): 11
Propulsion (HP): 850
Machinery: 1 diesel, 1 swiveling propeller

Construction:
YAGNameReclasBuilderKeelLaunchSvc
61MONOB IFeb 1969Zenith Dredge1 Dec 19423 Apr 19431 Oct 1960

Disposition:
YAGNameTInactStrikeDisposalFateMA Sale
61MONOB Ica 19922 Aug 19962 Aug 1996Trf--

Class Notes:
In the fall of 1959 BUSHIPS Code 310 (Director of Research and Development) informed Code 410 (Ship Design Division) that in support of the POLARIS program Code 345 (Ship Silencing Branch) was expediting planning to provide a barge suitably equipped to measure the radiated noise from submarines while operatieng either in the open ocean or in the Tongue of the Ocean (Caribbean area). The urgency of providing such a noise measuring barge was supported by the completion and nose ranging schedules of the POLARIS submarines. Existing noise measuring capabilities of BUSHIPS activities would be inadequate for accomplishing the required tests by September-October 1960. It was estimated that about nine months would be needed to secure long lead time items, prepare detailed conversion plans, and accomplish the actual conversion, indicating that the design study effort on this project should be initiated without delay. Code 310 therefore requested that Code 410 provide a design study for the conversion of a YW or YO to a mobile noise barge with a completion date of 15 December 1959.

Code 310 provided detailed characteristics for the barge. It was to be capable of operating as long as 30 days at sea with a total of 30 personnel on board. Its planned use as a noise measuring platform required noise isolation of all practicable machinery systems and operation at sea with minimum auxiliary equipment energized. Main propulsion equipment would not be required in the barge and would be replaced with an active rudder giving a speed of 3 knots and adequate to control the general movement and heading of the barge at sea. About 1,300 square feet of laboratory space would be added in the forward area of the barge, probably by modifying two existing tanks and adding decking to them. Two small generators were to be added in a new deckhouse in place of the present stack for quiet operation during noise trials, and for ultra-quiet operation and emergency use a battery was to be provided. All living and laboratory spaces were to be air conditioned, the equipment requiring special noise isolation. Hydrophones would normally be handled off the bow from a wooden grating deck to be established above the forecastle deck. A powered cable storage reel at about frame 14 and powered cable handling windlass (reversible) were required to handle a 4,000 foot length of 1.75" cable or 1,000 feet of a bundle of seven 1/2" cables lashed together. The barge would have a unit of BQS-3 and BQR-3A sonar arranged for overside operation and a fathometer for use in water depths to about 1000 fathoms. The barge was to be capable of being towed to and from operating areas (transits up to 1,000 miles) on a routine basis.

A hull study plan by the BUSHIPS Hull Design Branch for the conversion of a YW to a noise measuring barge was signed on 6 November 1959. On 15 December 1959 the type desk advised BUSHIPS that YW 98 had tentatively been selected for the conversion, but YW 87 was later substituted. On 21 December 1959 Code 300 (Research and Development Division) gave Code 400 (Ship Division) a list of requested changes to the original MONOB characteristics. The forecastle hydrophone handling platform along with the hydrophone and line stowage reels were to be deleted. A raised platform was to be added permitting the installation of winches and reels having a maximum combined static pull of 10 tons in any direction. An expanded metal, folding walkway was to be fitted extending around the stern along with a de-mountable "A" frame containing a fairlead similar to that shown on the hydrophone platform and capable of supporting a vertical load. The BQS-3 sonar was to be replaced with a "Sea Scanner" transducer. On 23 December 1959 Code 440 informed Code 345 that the basic design for MONOB for its prime mission of FBM noise ranging was scheduled for completion on 18 January 1960.

The former World War II water barge YW 87 was converted by the Norfolk Naval Shipyard between 1 July and 1 October 1960 to a "Mobile Noise Barge" (MONOB) for use in the Navy's ship-silencing program. She was designed to be towed to her operating area by a tug and would then use a 220 horsepower outboard unit to maneuver at about four knots within that area. (She later got a 850 BHP Caterpillar diesel and a swiveling propeller for independent mobility.) She was first used in January 1961 in the acoustic trials of a submarine in the deep (over 400 fathoms) and acoustically quiet waters in the Key West area.

In around 1966 the AUTEC (Atlantic Undersea Test and Evaluation Center) and TOTO (Tongue of the Ocean) acoustic ranges in the Bahamas entered service. MONOB I (MONOB ONE) operated from Port Everglades, Port Canaveral, and the US Naval Mine Defense Laboratory at Panama City, and was under the technical cognizance of the David Taylor Model Basin in Carderock, Md. and its successors. MONOB I was reinstated on the Naval Vessel Register in early 1969 as IX 309, probably at the same time as NEW BEDFORD (IX 308), and on 1 July 1970 was redesignated YAG 61. According to an unofficial insignia probably dating from the 1980s (see it HERE) "MONOB" (YAG 61) "sailed the triangle" between Florida, Exuma Sound, and the TOTO range, one of her functions being to tend large buoys. She later served in the Carderock Acoustic Trials Detachment to support the ballistic missile submarine silencing program. DEER ISLAND (YAG 62) was employed from 1982 in similar underwater sound programs. In 1992 MONOB I was scheduled to be replaced by HAYES (AG 195), which returned to service on 19 June 1992 after conversion from AGOR 16. She and DEER ISLAND were both transferred to Mexico on 2 August 1996.

Ship Notes:
YAGNameMANotes
61MONOB I(ex-IX 309 1 Jul 1970, ex-YW 87, compl. 17 Oct 1943). Trf. to Mexico 2 Aug 1996 as ARM RIO SUCHIATE (BI 05). (ARM = Mexican Navy ship, BI = Buque investigacion, or surveying ship)

Page Notes:
Compiled: 21 Oct 2021
© Stephen S. Roberts, 2021
Special sources: NARA: RG 19 Entry P 62 Box 98.