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The Northern Barrage: Taking Up the Mines 

Publication Number 4

The Historical Section of the Department of the Navy published seven monographs on the U.S. Navy and World War I between 1920 and 1923. The monograph The Northern Barrage: Taking up the Mines was the fourth in the series and was published in 1920. This 2017 essay from NHHC historian Chris Martin provides an introduction to the monograph as part of the centennial commemoration of World War I. The text of the monograph itself along with a downloadable PDF is available in the Navy Department Library Online Reading Room.


In 1920 the Navy published The Northern Barrage: Taking Up the Mines, which detailed how the U.S. Navy swept the North Sea of the mines the service had recently laid to create the North Sea Mine Barrage.

The narrative discusses the planning for the minesweeping operation in the North Sea and each of the Navy’s six minesweeping operations sequentially. Unlike many of the other publications in the series, subsequent research has not only shed more light on the Navy’s attempt to sweep the North Sea of American mines, it has also shown that some of the statements made in Publication No. 4 are wholly inaccurate. Perhaps the most egregious claim is that the Navy completely cleared the area in which it had sewn its mines. In fact, the minesweeping effort accounted for only 40 percent of the American mines. Rear Admiral Joseph Strauss, Commander Mine Force, U.S. Atlantic Fleet, assumed that the mines that were not swept had been destroyed. Many of the unswept mines eventually floated ashore over a period of years.[1] Another drawback that further historical research has exposed is that the publication’s focus on the North Sea Mine Barrage does not fully portray the Navy’s minesweeping efforts during World War I. Missing from the narrative is any discussion of Patrol Force Squadron 4, which swept mines off the coast of France and protected the vital transport of troops to the Western front.[2]

Watching the war in Europe develop, the Navy learned lessons that helped it prepare for the conflict it would later enter. The value of mine warfare became quickly apparent to Navy leadership and training commenced in earnest. In November 1916, the Atlantic Fleet conducted its first large-scale mine laying and minesweeping training operation 200 miles off Sandy Hook, New Jersey. The lessons learned in this exercise helped the Navy develop “general instructions and procedures” for the destruction or sweeping of enemy mines. This training enabled the Navy to quickly begin minesweeping operations after the United States entered the war on 6 April 1917.[3]

Because the United States had not developed its own technology to sweep or destroy German mines, the Navy borrowed what it needed from the Royal Navy, including a minesweeping device called the paravane. According to historian Tamara Moser Melia, paravanes were “torpedo-shaped floats that pulled out sharp wires from either side of a ship’s bow at the correct angle to cut mine moorings.”[4] The Navy’s extensive use of paravanes to sweep mines resulted in the creation of courses in paravane operation at the U.S. Naval Academy.[5]

The importance placed on minesweeping also influenced the structure of the fleet. In late 1916, the Office of the Chief of Naval Operations proposed the Navy construct “light draft” minesweepers that would be powerful enough to accompany the fleet and sweep mines at a speed of 10 knots.[6] Congress appropriated funds for 12 minesweepers in December 1916. The Bureau of Construction and Repair designed a steel-hull minesweeper with a 10-foot draft and a top speed of 14 knots. Put into production within weeks, the first of the 49 Lapwing­-class minesweepers built for the Navy between 1917 and 1920, Lapwing (Minesweeper No. 1) entered the fleet 12 June 1918.[7] After participating in multiple convoy escort cruises to Halifax, Nova Scotia, Canada, the Navy assigned her to the Mine Force on 7 May 1919.[8]

While Rear Admiral Strauss and the Mine Force Sailors may have been impressed by this new class of ship, Lapwing’s arrival presented a problem for the force. The MK 6 mine the Navy laid to create the Northern Barrage had a novel feature not seen in previous naval mines. It included a copper antenna that extended above the mine. The steel hull of a ship touching the antenna created an electrical connection that detonated the mine.[9] Because of the Lapwings’ draft, their steel hulls could have accidentally detonated mines laid close to the surface.[10]

Rather than attempt to solve this problem alone, the admiral created a board comprised of the minelayers’ commanding officers to determine the best strategy for sweeping all of the U.S.–laid mines.[11] The board recommended the use of a sweep wire attached to the stern of wooden “sweep vessels.” As the ship passed over or near a mine, the wire would come in contact with the mine’s antenna and detonate it. After all surface mines had been destroyed, heavier ships such as the Lapwing could then safely traverse the mine field and sweep mines laid well below the surface. This plan appeared to be the only viable option, therefore, the admiral began considering chartering wooden-hull vessels from the Admiralty.[12] Thankfully for the Mine Force Sailors, they were saved from this extremely dangerous undertaking by successful experiments instigated by a suggestion from a junior officer.

While the senior officers in the Mine Force endorsed extremely dangerous minesweeping tactics, Ensign D. A. Nichols, who had worked on the problem alone in parallel with the board, suggested the development of an electrical device that would automatically detonate any mine that came within a specific radius of the minesweeping vessel. Unfortunately, subsequent experiments determined that to produce the electrical charge necessary to detonate mines at a safe distance, the proposed device would be too large and elaborate for installation on the minesweepers.

Although the idea was not practicable, it was not a failure because the experiments undertaken to study it caused the ultimate solution to the problem to “automatically suggest itself.”[13] Instead of trying to clear the Northern Mine Barrage by detonating each mine, the Navy reversed the ensign’s idea and developed a method that prevented the mines from exploding when struck by a ship; the mines could then be plucked from the sea and taken ashore.[14]

After Ensign Nichols’s proposal, Navy engineers realized that if they raised the chemical potential of each ship’s hull to that of the mine’s copper antenna, the mine would not explode if touched by the steel hull. The reaction would be as if two pieces of copper touched each other. This method prevented electrical current from closing a circuit from the ship’s hull to the relay inside the mine. The mine, therefore, would not explode. To do this, several hundred feet of lead line was connected to the negative terminal of the ship’s electrical generator. The free end of the lengthy lead was towed behind the ship. Not only did this device prevent mines from exploding on contact with a steel hull, it also produced a “partial effect” on some mines within several hundred feet of the ship, making them less susceptible to accidental detonation.[15]  In addition to being much safer, this new method allowed the Americans to use their new steel-hull vessels for their intended purpose—sweeping mines.

The willingness of the senior officers of the Mine Force to examine Ensign Nichols’s suggestion offers an illustration of the importance of initiative, one of the four core attributes of the Navy identified by Chief of Naval Operations (CNO) Admiral John H. Richardson in his January 2016 publication, A Design for Maintaining Maritime Superiority.

In this, the CNO defines the meaning of initiative as something beyond “everybody strives to be the best they can be.” It also means that the Navy must “foster a questioning attitude and look at new ideas with an open mind. Our most junior teammate may have the best idea [and] we must be open to capturing that idea.”[16] While the Nichols suggestion was not practical, it did spur others to consider the possible existence of additional options for clearing the Northern Mine Barrage.

                -Chris Martin, NHHC Historian                                                    

[1] Tamara Moser Melia, “Damn the Torpedoes”: A Short History of US Naval Mine Countermeasures, 1777–1991 (Washington, DC: Naval Historical Center, 1991), 38.

[2] Cmdr. G. N. Hinkamp, “Pipe Sweepers,” Proceedings, Vol. 46, No. 9, (Sep 1920), 1477–84.

[3] Melia, “Damn the Torpedoes,” 29–30. 

[4] Melia, “Damn the Torpedoes,” 31.

[5] Melia, “Damn the Torpedoes,” 32.

[6] Melia, “Damn the Torpedoes,” 33–34. 

[7] Naval History and Heritage Command, Dictionary of American Naval Fighting Ships, s.v. “Lapwing I (Minesweeper No. 1),” (Washington, DC: Naval History and Heritage Command, n.d.),

[8] US Navy North Sea Minesweeping Detachment, Sweeping the North Sea Mine Barrage, 1919, (New York: The Press of Joseph D. McGuire, 1919), 136.

[9] Department of the Navy, The Northern Barrage and Other Mining Activities (Washington, DC: Government Printing Office, 1920), 105–120.

[10] Department of the Navy, The Northern Barrage: Taking Up the Mines (Washington, DC: Government Printing Office, 1920), 7.

[11] The Northern Barrage: Taking Up the Mines, 9.

[12] The Northern Barrage: Taking Up the Mines, 9.

[13] The Northern Barrage: Taking Up the Mines, 10.

[14] The Northern Barrage: Taking Up the Mines, 10.

[15] Harry C. Armstrong, “The Removal of the North Sea Mine Barrage,” Warship International, Vol. 25, No. 2 (June 1988), 140.

[16] Chief of Naval Operations Admiral John H. Richardson, A Design for Maintaining Maritime Superiority, (Washington, DC: Department of the Navy, 2016),

Published: Fri Oct 27 14:21:47 EDT 2017