USS Chimo(ACM-1) Class

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USS Barricade (ACM-3) circa 1945
Click on this photograph for links to larger images of this class.

Class:        CHIMO (ACM-1)
Design:        Army MP
Displacement (tons):        880 light, 1,320 full
Dimensions (feet):        188.2' oa, 168.7' wl x 37.0' e x 12.5' mn.
Original Armament:        1-40mmS 4-20mm (1944: ACM 1-3)
Later armaments:        1-40mmS 6-20mm (1945: all)
Complement:        69 (1944)
Speed (kts.):        12.5
Propulsion (HP):        1,200
Machinery:        Reciprocating (Skinner Unaflow), 2 screws

Construction:

ACM	Name	Acq.	Builder	Keel	Launch	Commiss.
1	CHIMO	7 Apr 44	Marietta Mfg	1942	1943	7 Apr 44
2	PLANTER	4 Apr 44	Marietta Mfg	1942	1943	4 Apr 44
3	BARRICADE	7 Apr 44	Marietta Mfg	10 Oct 41	1942	7 Apr 44
5	BARBICAN	6 Jan 45	Marietta Mfg	1941	1942	24 Mar 45
6	BASTION	4 Jan 45	Marietta Mfg	1941	1942	9 Apr 45
7	OBSTRUCTOR	4 Jan 45	Marietta Mfg	1941	1942	1 Apr 45
8	PICKET	2 Jan 45	Marietta Mfg	1941	1942	6 Mar 45
9	TRAPPER	2 Jan 45	Marietta Mfg	1941	1942	15 Mar 45

Disposition:

ACM	Name	Decomm.	Strike	Disposal	Fate	MA Sale
1	CHIMO	21 May 46	23 Dec 47	9 Apr 48	MC	18 Feb 48
2	PLANTER	22 May 46	23 Dec 47	9 Apr 48	MC	17 Feb 48
3	BARRICADE	28 Jun 46	19 Jul 46	28 Jun 46	USCG	--
5	BARBICAN	12 Jun 46	19 Jul 46	12 Jun 46	USCG	--
6	BASTION	18 Jun 46	19 Jul 46	18 Jun 46	USCG	--
7	OBSTRUCTOR	28 Jun 46	19 Jul 46	28 Jun 46	USCG	--
8	PICKET	24 Jun 46	19 Jul 46	24 Jun 46	USCG	--
9	TRAPPER	2 Jul 65	1 Jul 65	2 Jul 65	MA/D	18 Oct 67

Class Notes:
No FY (transferred). Until 1949 the Army's Coast Artillery Corps was responsible for maintaining minefields to protect American harbors and coastlines from hostile ships. These minefields consisted of controlled mines, which were linked by electrical cables to control stations ashore. The Army used mine planters to lay both the mines and their control cables. The Army had nine miscellaneous vessels of this type in November 1940 when it issued its first specifications for a new 188-foot twin-screw, steel, steam-propelled mine planter. It modified these specifications in May 1941 and in April 1944. Sixteen ships of this type were built by the Marietta Mfg. Co. at Point Pleasant, W.Va. as their hulls 474 to 489, twelve under a contract of 18 Jan 41 and four under a contract of 4 Aug 41. The Army designated them MP-1 to MP-16 respectively and named them after Army officers. MP 1-12 were accepted between April and December 1942 and MP 13-16 between February and May 1943. The Army's mine planters were unusual in having Skinner Unaflow engines, as did the Navy's LSD 1-8 and its CASABLANCA (CVE 55) class escort carriers. In a Unaflow or uniflow (generic name) engine, steam entered alternatively at the ends of the cylinder, which were always hot, and exhausted at the center, which was cooler, reducing the energy spent in a conventional reciprocating steam engine in alternatively heating and cooling the cylinder walls.

By 1944 it was clear that there was no longer any serious threat to American harbors and the Army began releasing its mine planters for other uses. The Navy received three of the new ships in 1944 and five more in 1945. (After World War II it acquired six of the remaining eight ships of the class, which will be listed here separately as the CAMANCHE, ACM-11 class.) The Army offered three to the Navy on 15 Mar 44 but withdrew the offer on 20 Mar 44 after it learned of a possible requirement to rehabilitate the controlled mine field in the Manila-Subic Bay area. The Navy had an urgent and immediate need for the three vessels to round out the combat minesweeping and disposal units in the Mediterranean and withdrew the Manila requirement, upon which the Army transferred the ships. Acceptance of the first three was directed by CNO on 30 Mar 44 and their names and classifications ACM 1-3 were approved on the same date. ACM-1 was sent to England to support the Normandy invasion and the other two were sent to the Mediterranean to support the landings in southern France, all after very brief conversions at Norfolk.

On 18 Aug 44 ComServRon 6 in the Pacific requested the conversion of some Liberty (EC-2) ships for the purpose of providing repair facilities and logistic support for minecraft. CominCh replied on 16 Sep 44 that such conversions were not then possible because of present needs for shipping and congestion of conversion facilities. He added that no vessels other than ACM 1-3 upon completion of their present duty in European waters were available for this purpose. These ships had been supporting YMS type minesweepers as tenders and flagships and their accommodations had been found to be excellent. In the meantime he suggested that two other ship types, the ARG and the CM, could be used for this purpose. (See the APB-45, AG-68, and AG-73 classes for responses to similar requirements.) On 30 Dec 44, however, CNO directed the acquisition of five more Army mine planters for conversion to minesweep gear and repair ships. Each was converted to a tender and flagship for a squadron of YMS minesweepers and carried stocks of YMS minesweeping gear and diesel engine and other spare parts. The facilities they provided for the YMS included medical and dental care, radio maintenance and repair work, handling of pay and pay accounts, radio guard services, furnishing of fresh water, cleaning of evaporators, furnishing of ice cream, movie entertainment, etc. ACM 1-3 returned from Europe in March, January, and June 1945 respectively, were sent to Charleston for conversions similar to ACM 5-9, and then joined their sisters in the Pacific.

Six of the eight ships were transferred to the Coast Guard after the war, including TRAPPER (ACM-9) which became the Navy's cable repair ship YAMACRAW (ARC-5) in 1959. The Navy took over six more ships of this class from the Army in 1949-1951 which are listed as the CAMANCHE (ACM-11) class in the postwar Supplement.

Ship Notes:

ACM	Name	Notes
1	CHIMO	Ex Army COL. CHARLES W. BUNDY (MP-15, completed Apr 43). Converted by the Norfolk Navy Yard 10-28 Apr 44. Sold (awarded) by MC to Foss Launch & Tug Co, Seattle, Wash. Merc. DAY ISLAND (fishing vessel) 1963. Sank 7 Dec 77 in the Caribbean.
2	PLANTER	Ex Army COL. GEORGE RICKER (MP-16, completed May 43). Converted by the Norfolk Navy Yard 4-27 (or 20) Apr 44. Sold (awarded) by MC to Foss Launch & Tug Co, Seattle, Wash. Merc. SAN JUAN (fishing vessel) 1963.
3	BARRICADE	Ex Army COL. JOHN STOREY (MP-8, commissioned 7 Nov 42). Converted by the Norfolk Navy Yard 11-29 Apr 44 . To USCG as buoy tender MAGNOLIA (WAGL/WLB-328, in commission 3 Sep 46-13 Aug 71). Sold 15 Nov 72.
5	BARBICAN	Ex Army COL. GEORGE ARMISTEAD (MP-3, completed 23 Aug 42). Converted by the Charleston, S.C. Navy Yard 6 Jan-25 Mar 45. To USCG as buoy tender IVY (WAGL/WLB-329, in commission 21 Apr 47-26 Nov 69). Merc. BALBOA (1977), SEA FOX (1981).
6	BASTION	Ex Army COL. HENRY J. HUNT (MP-2, completed 30 May 42). Converted by the Charleston, S.C. Navy Yard 4 Jan-14 Apr 45. To USCG as buoy tender JONQUIL (WAGL/WLB-330, in commission 29 Aug 46-15 Sep 69). Sold 6 May 70.
7	OBSTRUCTOR	Ex Army 1st LT. WILLIAM G. SYLVESTER (MP-5, completed 7 Sep 42). Substituted for BRIG. GEN. ROYAL T. FRANK (MP-12) as ACM-7 ca. 30 Dec 44. Converted by the Charleston, S.C. Navy Yard 4 Jan-4 Apr 45. To USCG as buoy tender HEATHER (WAGL/WLB-331, in commission 1 Feb 47-15 Dec 67). To Seattle Community College via Dept. of Health, Education & Welfare 12 Apr 68.
8	PICKET	Ex Army GEN. HENRY KNOX (MP-1, completed 15 Apr 42). Converted by the Charleston, S.C. Navy Yard 2 Jan-5 Mar 45. To USCG as buoy tender WILLOW (WAGL/WLB-332, in commission 20 Sep 47-10 Oct 69). Sold 22 Feb 72, later merc. KNOX and HENRY KNOX.
9	TRAPPER	Ex Army MAJ. GEN. ARTHUR MURRAY (MP-9, completed ca. Nov 42). Converted by the Charleston, S.C. Navy Yard 2 Jan-15 Mar 45. Decomm. and to USCG 20 Jun 46 as cable layer YAMACRAW (WARC-333), stk. 19 Jul 46. Loaned to Navy by USCG 16 Apr 59 (formally returned 1 Jun 59) and commissioned 30 Apr 59 as the cable repairing ship USS YAMACRAW (ARC-5). Administratively returned to USCG 1 Jul 65 and to MA for disposal. Scrapped by 1 May 68. For more on her postwar career with photographs see the YAMACRAW (ARC-5) class in the postwar Supplement.