Sinp’o (40°02'N 128°12'E) / Mayang Do Naval Base

Mayang Do is one of two North Korean submarine bases. It provides operation and logistical support for submarines, antisubmarine craft, and patrol craft.

The base is located in a natural harbor on the east coast, approx. 30 miles NE of Hamhung. The harbor is located on the north side of Mayang-do, an island that lies 1 mile of the mainland south of Sinp'o. The facilities are located in two bays with central depths of 48-59 feet, separated by a peninsula. There are two approaches: the western channel is 1/2 mile wide with a controlling depth of 30 ft.; the eastern channel is 1 mile wide with a controlling depth of 52 feet. Tides and currents are negligible, and ice does not interrupt navigation.

Anchorage in the strait provides many free-swinging berths over a mud and sand bottom, with depths of 20-60 ft. Berthing facilities alongside are provided by 1830 ft. of principal wharfage at 4 quays and one pier. Depths alongside range from 10 to 21 feet. A POL pier and supplemental wharfage for small craft are also present. There is extensive warehouse and POL storage present.

The shipyard is reported to have a 360 x 70 foot graving dock, a 270 foot marine railway, and other facilities for repair of sumbarines and patrol craft. Intelligence from the 1970s reported that the installation was being expanded with additional wharfage, storage, barracks, and shipyard facilities.

Sinp’o (40°02'N 128°12'E) stands at the head of Sinp’o Hang, the largest of the coves N of Mayang Do. The harbor, sheltered from all except S winds, is approached via the strait lying between Mayang Do and the mainland. The E entrance is free from dangers in the fairways; the W entrance is comparatively shallow and should not be used by large vessels.

In December and January, thin ice forms in the inlets on the coast of Mayang Do, but the strait is never icebound. Some fog, usually accompanied by E winds, occurs from April through June. The prevailing winds are from E to SE in spring and summer, S to SW from late summer to early autumn, and W to NW in winter. The E and recommended entrance of the strait is unobstructed over a width of about 0.8 mile between the reef extending about 183m off the NE point of Mayang Do and Taegu Do, close off the N side of the strait. The S side of this islet is cliffy and somewhat conspicuous. Sinp’o Hang has depths of 5.5 to 9.1m.

The E part of the mainland N of Mayang Do consists of spurs of hills which terminate in three small and rocky points. The W part, low and sandy, extends to Pongsu Pando which serves as a good mark for the W entrance of the strait. Landmarks for Sinp’o Hang include a black rock, 11.9m high, close off Saam Dan, the W entrance of the harbor and two chimneys, three radio masts, and a flag staff, all on the W side of the harbor. The above black rock can be identified from both the E and W entrances of the strait.

Putting forth the policy of "modernizing fishing with large-scale and highly efficient boats to suit the characteristics and situation of our country's fishery industry", the great leader Kim Il-sung helped build many large-size fishing boats, including 7,750-ton stern trawlers and 5,000-ton refrigeration vessels, during the Six-Year Plan period so as to help catch fish in deep waters under any weather conditions. Thanks to "the great leader's wise leadership and consideration", many large-size and small-size fishing boats were built, and "modern scientific techniques and equipment were extensively introduced into the fishery sector for fishing operations during the Six- Year Plan period". During the Six-Year Plan period the Sinpo and Kimchaek ports were built and expanded. In addition, fishing bases in Yanghwa and Hongwon districts were reorganized as deep-sea fishing bases.

South Hamgyong Province has many fishery stations ranking among the biggest ones in North Korea and scores of small and middle fishery cooperatives. The Sinpo Fishery Station, one of the dependable pelagic fishing bases, has factory mother ships of 10,000-ton class or more and other big vessels. It developed medium- and small-scale fisheries and improved their technical equipment.

The Agreed Framework defused tensions on the Korean Peninsula and resulted in various trade-offs between North Korea and the United States. the United States agreed, among other things, to create an international consortium of member countries to replace North Korea’s graphite-moderated reactors with two light-water reactors by a target date of 2003. The resulting consortium — established in March 1995 — was called the Korean Peninsula Energy Development Organization (KEDO). In August 1997, groundbreaking for the reactors occurred in the Kumho district of Sinpo — the port city on North Korea’s east coast. This scheme fell apart a few years later.