Seawall @ Jake (Juliet) Basin Sasebo, Japan

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The Sasebo, Japan based mine sweeping boat division began as the COMinRon-3 Boat Division sometime following the outbreak of the Korean War in June 1950. In early 1951 it was commissioned as Mine Sweeping Boat Division ONE, still reporting to COMinRon-3, cosisting of two 40′ motor launches and a dozen or more LCVP’s as minesweepers. Conversion to mostly 50′ motor Launches (modified with decks and even cabins, before the end of the war. At the Korean Armistace, the Division was re-named Mine Division 111, reporting to MinRon 11 in Long Beach, CA. In 1958 their 50′ Motor Launch Minesweepers (MLMS) were replaced by newly built 36′ Mine Sweeping Launches (MSL’s) built bt Sagstad Shipyards in Seattle, and powered by Boeing 502-10-C Gas Turbine Engines.

Stroud, the SN on the bow, is reading the signalled semaphore message indicated by his raised arm. His semaphore flags are likely in his right hand. The Element Commander of five MSL’s is likely signalling an upcoming turn. The navigation “balls” indicate we are towing gear on both port and starboard sides, a signal for civilian traffic to stay clear. The main propulsion engine, a Boeing 502-10C gas turbine is in the foreground. At full power when towing, the 502-10C generates 110-130db of noise similar to any jet engine. The power package loaded forward, is a diesel powered generator powering our acoustic minesweeping hammer, a noisemaker when towed far behind, is intended to explode acoustic mines well aft of the boat. We are also streaming moored Oropesa sweep gear.

Ed Sinclair

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Edward Sinclair

View MSL video here produced by the USN in 1959. this is one of a series of four videos produced by the Navy covering 36′ Mine Sweeping Launches for assault minesweeping in Rivers, 57′ Mine Sweeping Boats as Harbor and Channel Minesweepers, 145′ Mine Sweeper Coastal, and 172′ Mine Sweeper Ocean. These are all wooden hulled vessels specifically designed from experiences in the Korean War losing steel-hulled minesweepers to Russian magnetic mines.

The first photo shows the 36′ MSL being tested following installation of Boeing Gas Turbine engines 502-10C and outfitted with all its gear at the Seattle shipyard in the mid-late 1950′s. Note the hull numbers have not been painted on the bow and stern yet. The photo below is a close up of the Boeing 502-10C main propulsion engine:

Sometime around 1958 twenty MSL’s were delivered to MINPAC Long Beach, CA for acceptance and eventually trans-shipped to Sasebo, Japan Mine Division 33.

Mine Division 33 was preceded by Mine Division 111 in Sasebo, Japan. Mine Division 111 in Sasebo, Japan was created on the date the Korean War ended in August 1953. Prior to the desgination as Mine Division 111 on that date, the division was designated as Mine Sweeping Boat Division ONE in Sasebo, Japan. In 1950 and into 1951 the boat division was born as COMINRON THREE Boat Division and operated in the early months of the Korean War under that designation. Originally, two 40′ Motor Launches shanghied from the U.S.S. Boxer, and fourteen LCVP’s delivered by the U.S.S. Catamount made up the complement of mine sweeping boats for most of the Korean War. 50′ motor launches that were highly modified by the Ship Repair Depot in Sasebo (decks and pilot houses added) in search of the ideal mine sweeping boat specifications, started arriving in 1953. These were designated as Mine Sweeping Motor Launch (MSML) and the hull designations were abbreviated MS.

This was edicted by the Navy brass, since BUSHIPS designed an entirely new craft 57′, in the early 1950′s designated as MSB’s and could not leave the Korean War boats, some of which actually swept as many as  84 mines in combat, with the combat earned designation of Mine Sweeping Boats! Stay tuned for the BUSHIPS debacle that was the 57′ MSB, which failed it primary mission as a Harbor and Channel Minesweeper, and failed the logistics of being carried to war on mine sweeping mother ships.

The MSL’s were delivered to Sasebo, Japan and were transported around SE Asia on LSD’s primarily, as they had been transported throughout the Korean War. Actually, early in the Korean War an LST had been modified as COMINRON THREE flagship, and carried the two motor launches and fourteen LCVP’s, but it was determined winching these in open seas up to the tank deck in the LST’s was too difficult, and next to impossible in stormy seas. So, they gravitated to using LSD’s, and hoisting them aboard with their cranes, placing the MSL’s on prefabricated wheeled skids in the well deck. The MSL’s lacked the flat bottoms of LCVP’s, and did not have skegs to protect their propellers, and therefore could not be turnbucled down directly on the well deck like the LCVP’s and motor launches were transported. BUSHPS made the same mistake with the 57′ MSB design a curved bottom.

MSL’s on wheeled skids in the well deck of U.S.S. Epping Forest. The Epping Forest, LSD-4 in Korea, re-designated MCS-7 in 1961 when she was transferred to MINPAC as Mine Countermeasures Support ship = MCS. The same mine sweeping mother ship duties that approximately17 LSD’s performed in Korea.

MSL-13 being hoisted aboard U.S.S. Epping Forest in Vietnam 1967

MSL’s maneuvering in harbor circa 1965 Sasebo or Subic Bay.