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

Three minute introduction only. WP limits videos to 32mB

This movie, The Small Boat Navy, was sent to me by a shipmate in 2013. It appears to be a very well done documentary, post 1968, regarding Vietnam Naval Coastal Surveillance and Riverine Warfare. There is a section devoted to minesweeping the Long Tau Shipping Channel (Saigon River Complex)using 57′ Mine Sweeping Boats – MSB’s. Nothing is mentioned regarding the 36′ Mine Sweeping Launches – MSL’s of Mine Division – 33 transported by the USS Epping Forest MCS-7 Who arrived in July 1964 for the  check sweeping of Cam Ranh Bay, Nha Trang Harbor, and Da Nang Harbor. The EF MCS-7 transported our ten MSL’s to Vietnam eighteen times through 1968. Our XO of MinDiv – 33 said he attended a meeting in early 1966 in Saigon, where MACV was considering our 36′ Mine Sweeping Launches for the Long Tau Shipping Channel minesweeping effort. MSL’s were eliminated in favor of the 57′ MSB’s due to the MSB’s larger size, pilot house, bunk arrangements, head facilities, and general sea worthiness. Also, the MSB was fitted with ceramic armor, and had a small crane for deploying oropesa minesweeping gear, and the newly designed chain drag sweep gear, for clearing command detonated mine wires from river shorelines to mines planted in the river.

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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.

Since two brutal recessions have interfered with my ability to finish researching and writing more of the book (I needed to find employment as a result) the book research and writing have been limited, but I am still gaining more information as people read this article. I am planning on starting with a website which gives me the ability to share thousands of items that cannot be included in a book.

I may be contacted for information, or unique contributions of photos, memorabilia, documents, or any anecdotes you would feel worthy – in telling the history of small boat minesweeping.

Ed Sinclair – 2011