Succeeding them following the Korean Armistice was Mine Division – 111 which had almost totally converted to 50′ Motor Launch Minesweepers, heavily modified by Ship Repair Depot in Sasebo with decks, some with enclosed pilot houses and masts. They were forced by Navy wisdom to relinquish their MSB designations (Mine Sweeping Boats) and reclassify their boats as Motor Launch Mine Sweepers – MLMS. This was due to BuShips having given the MSB designation to a new 57′ minesweeper class they were developing.

In 1958 these boats were replaced by newly built 36′ Mine Sweeping Launches (MSL’s), powered by Boeing Gas Turbine Type 502-10C. Twenty MSL’s were delivered to WestPAC split between Sasebo and Long Beach, CA. Following this re-organization their LCVP’s and MLMS’s were given to Taiwan, Korea, and Vietnam. The Division was re-named Mine Division – 33, and in 1961 the USS Epping Forest LSD-4, was transferred to MinFlot 1 in Sasebo and re-designated MCS-7. Mine Countermeasures Support ship.

In August 1966 MinDiv – 33 was decommissioned and tranferred aboard the USS Epping Forest mCS-7 as the Boat Division. In Fall of 1968 the USS Epping Forest was de-commissioned. The Boat division was sent to the Sasebo Seawall for the winter. The following Spring the USS Catskill MCS-2 arrived in Sasebo as the new mothership. During which in the waning budgets due to Vietnam, the Catskill was decommissioned. Minesweeping Boat Divisions homeported in Sasebo no longer exist.

I think the Japanese perspective of what occurred with the Sasebo facilities post WWII is very interesting, Life in Base Town Sasebo

Ed Sinclair

W.J Miller QMC USN, a writer for the USN All Hands Magazine wrote a nice 6 page story on the AMS minesweepers (136″) and the CoMinRon 3 Boat Division sweepers (36′) - Which were later redesginated as Mine Sweeping Boat Division ONE for the remaider of the Korean War. Following the Korean Armistice in August 1953, the unit became Mine division – 111 homeported in Sasebo. In 1958 it was further redesignated Mine Division – 33 and reorganized to report to COMINRON THREE/MINFLOT 1 Sasebo.

Ed Sinclair

Seawall @ Jake (Juliet) Basin Sasebo, Japan

CLICK ON PHOTO TO ENLARGE – Again to enlarge More

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

A second major discovery in the use of Russian mines by the enemy in Vietnam, the North Vietnamese hauled segments of the more modern Russian ground mines, the 24″ cylindrical HAT II acoustic-magnetic bottom mines down the Ho Chi Minh Trail, to the Cua Viet River. These have modular sections, and are up to 6 ft long when assembled. One was believed to have exploded and capsized an LCU/YFU full of munitions, killing six of the seven sailors aboard, while traversing the Cua Viet River to the Dong Ha Marine Base upriver.

EOD Divers found another HAT II fully assembled and planted outside the bar at the mouth of the Cua Viet river, and rendered it safe. Luckily, no large USN ships could navigate the shallow Cua Viet River, and did not venture across the bar heading upriver.

It is believed that the North Vietnamese, or like during the Korean War, Russian advisors, assembled these mines, and tied a series of floation devices around or alongside them, swam into the river floating these mines, and deflating the flotation devices with knives to “plant” these ground mines on the river bottom. These mines were believed to have acoustic-magnetic trigger mechanisms.

During the Battle Of Dai Do Village, in the Sring of 1968, Naval forces battling the NVA north of the Cua Viet river spotted suspicious activity on the north bank during the battle, and sent ground troops to investigate later. They discovered segments of these HAT II cylindrical mines on the river bank. EOD divers from the Cua Viet Base discovered parts for eight complete mines, evidently hauled down the Ho Chi Minh Trail in peices by the North Vietnamese. This was the NVA attempt to close down the Dong Ha-Cua Viet ammo supply line, and overrun the USMC Base at Dong Ha. MSL’s from the USS Epping Forest left Da Nang the day this discovery was made, and sailed north to Cua Viet, prepared to sweep the river. This minesweeping unit consisting of ten 36′ Mine Sweeping Launches, now designated as the Epping Forest Boat Division, formerly Mine Division 33, had moved aboard the USS Epping Forest permanently in the summer of 1966. They allegedly towed a WWII “iron rail” magnetic sweep, believed to be a section of magnetized railroad track, packed inside a PVC pipe, behind their 36′ Mine Sweeping launch. No detonations resulted from their sweeps of the Cua Viet, the scene of the deadly LCU/YFU explosion days earlier.

Almost all remaining mine planting activity in Vietnam in Bays and Rivers consisted of home made explosive devices, manufactured in the jungle from unexploded US ordnance explosives, trash, and battlefield junk such as tin cans, shell casings, aircraft wing tanks, and various containers. The most frequent were command detonated explosives planted in the rivers, and detonated by an enemy fighter from a foxhole alongside the river, using dry cell batteries.

OPNAV 1650 Awards EPPING FOREST LSD 4-MCS 7

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.