
Type N3 ship

Type N3-S ships were a Maritime Commission small coastal cargo ship design to meet urgent World War II shipping needs, with the first of the 109 N3, both steam and diesel, type hulls delivered in December 1942. 
A total of 109 N3 ship were built by:
Design.
The N3-S, with "S" designating "steam," came in two versions patterned on and sometimes themselves termed Baltic Coasters. One, the N3-S-A1 was coal fired reciprocating steam powered at British request with the N3-S-A2 variant being oil fired and both types intended largely for wartime lend lease.
The basic design characteristics were:
However, as the built dimensions and tonnage of the two N3-S types varied somewhat from the basic design and each other. The fourteen Penn-Jersey N3-M-A1 vessels had a different profile in addition to being diesel powered.
N3-S-A1.
All of the 36 N3-S-A1 vessels, 2,800 DWT, delivered from December 1942 through May 1945, went to Britain and those surviving the war tended to be sold commercial but one; built as the "Freeman Hatch" and lastly named "Houston", gaining some notoriety being sunk during the failed Bay of Pigs invasion in 1961. Nine built by Leathem D. Smith Ship Building & Coal Company in Stureon Bay, Wisconsin. Nine built by Pacific Bridge Company of San Francisco, California. Walter Butler Shipbuilders Inc. of Superior, Wisconsin built 18.
N3-S-A2.
Of the 76 proposed N3-S-A2, 2,757 DWT, vessels 59 were built with the first delivered March 1944 and the last after the war in November 1945 with 17 scheduled ships canceled. All were operated by commercial firms with some going to Poland, Greece and Britain. Twenty-three were allocated by the War Shipping Administration to the Army for use as transports. Of those, 19 were operated in the Southwest Pacific Area as part of the Army's permanent local fleet with the first arriving 5 September 1944 and the last in December 1945. A few found their way into non-commissioned U.S. Naval service by way of Army as postwar auxiliaries with at least some leased to Korea: "Alchiba" (AK-261), "Algorab" (AK-262), "Aquarius" (AK-263), "Centaurus" (AK-264), "Cepheus" (AK-265) and "Serpens" (AK-266). Avondale Marine Ways Inc. of Westwego, Louisiana built 14. Ingalls Shipbuilding Corporation of Decatur, Alabama built 9. McCloskey & Company of Tampa, Florida built 15. Pendleton ShipYard Company of New Orleans, Louisiana built 4. Pennsylvania ShipYard Inc. of Beaumont, Texas built 9. Walter Butler ShipYeard Inc. of Duluth, Minnesota built 2. Walter Butler ShipYard Inc. built 6.
N3-M-A1.
A third variant, the N3-M-A1, at 2,900 DWT, was a very limited design with diesel-powered ships with superstructure aft instead of amidships. Fourteen built at Penn-Jersey Shipbuilding Co. of Camden, New Jersey. Barnes-Duluth shipyard built 12. The N3-M-A1 were 2,483 gross tons with a length of 291 feet by beam of 42 feet. Number one and two holds were 56 feet long with number three being 28 feet in length. An example is the "Junior N. Van Noy".
The ships were constructed under U.S. Navy supervision as Navy had assumed the Maritime Commission contracts for the Penn-Jersey yard and was allocating vessels of this type for its own and British use. Four of the fourteen ships of this type retained the original form and were transferred to Britain as BAK-1, BAK-2, BAK-3 and BAK-4 and operated by Currie Line for the Ministry of War Transport as "Asa Lothrop", "Lauchlan McKay", "John L. Manson" and "Nathaniel Mathews". 
 One was retained by the U.S. Navy as the with the remaining nine transferred to the U.S. Army to be converted to U.S. Army Engineer Port Repair ships. The conversion placed machine, welding and carpenter shops in number two hold along with generators and air compressors supporting engineering work. Number one hold was reserved for construction machinery with number three containing repair stock, portable generators, refrigerated stores and quarters. The ships also carried portable salvage equipment, including diver support, five ton capacity crawler crane, other lifting equipment and a pontoon barge. The most notable feature was addition of a forty-ton cathead derrick for heavy salvage.