Sweeping the Northern Barrage
Like many of the most prominent military tactics employed during the First World War, the use of mines represented a new technology that had received little interest or priority before the war, only to become a major component of wartime strategy during it. For the United States Navy, the first minelayer was not commissioned until 1912. With the advent of war in 1914, the Navy began converting tugs to minesweepers to combat the growing menace, but only envisioned these vessels as mere components of the Atlantic Fleet, rather forming their own discrete force. Following the entrance of the United States into the war in 1917, the Navy began to realize the threat posed by the pervasive presence of enemy mines and rapidly embraced the use of mines as a tool of war. The navy department readily seized upon the tools and tactics the British developed to combat the “pills of perdition”, equipping its fastest destroyers with minesweeping gear.
In 1916, the General Board had recommended-and Congress approved-the construction of twelve minesweepers, whose construction began in earnest; the total constructed would number over fifty by the end of the war. 180-feet long with steel hulls, these vessels came to be known as the Bird class, and served as United States Navy’s main minesweeping force during and after the war. The first of these ships, Lapwing, launched in March 1918, with the other Bird vessels joining it soon thereafter. Despite the rapid construction of these vessels, however, Admiral William S. Benson, Chief of Naval Operations, hesitated to send them the European Waters. Benson believed that, if he dispatched the minesweepers to the war zone, then the Germans would take the opportunity to blockade the Atlantic Fleet by mining the coastal waters where it was stationed. Consequently, the United States Navy relied upon several converted wooden fishing trawlers to aid in keeping French coastal waters free of mines in order to protect troop transport convoys, a task at which these vessels succeeded admirably.
One of the Navy’s greatest achievements in fighting the war at sea was the creation of the North Sea Mine Barrage, or Northern Barrage. Conceived as an offensive means of containing the German High Seas Fleet and making it difficult for German U-Boats to act with impunity in targeting Allied shipping in the North Sea, the North Sea Mine Barrage was the “most extensive minefield ever planted—more than six thousand square miles, some 260 miles long, stretching from the Orkney Islands to the Norwegian coast.” Working with the British Navy, the American mine force laid over 70,000 mines, 56,000 of which were the newly-designed American Mark VI mine, before war’s end.
Given both the extent of the barrage-its size, depth of water, and number of mines laid-as well as the nature of the Mark VI mine, the sweeping of the barrage proved a unique challenge. As opposed to being a contact mine such as the ones employed by the other belligerent powers, the American mine was an “influence” weapon, which required only the tiniest bit of metal to pass near an antenna connected to the mine in order to create an electrical charge that would cause the mine to explode. Consequently, even before the signing of the Armistice in November 1918, naval leaders had begun considering how best to remove the mines so that they would not be a threat to peacetime sailing. In October 1918, Rear Admiral Joseph Strauss, the commander of the Mine Force, asked his officers to consider the problem and suggest methods in which the mines could be swept up safely. At the end of the month, the Allied Naval Council met in London to discuss the overall problem of the tens of thousands of mines laid by both allies and enemies that were now scattered throughout European Waters. Overall, the Allied Naval Council agreed that the best solution was to leave it to each of the belligerent powers to clear the mines from their respective territorial waters. The major exception to this consensus was the Northern Mine Barrage, the removal of which would fall to the United States and Great Britain. Benson delegated this task to Strauss and the mine force, which began its work in earnest.
Already aware of the difficulties that sweeping the Northern Barrage presented, Strauss and the officers in the mine force recognized that they first had to determine how they could remove the mines with the greatest safety and efficiency. Without a known method as to how to sweep the Mark VI mine, the leaders of the mine force consulted with both British and American experts, only to find no ready answers. Due to the sensitivity of the mine antennae to metal, using the new steel-hulled Bird sweepers was out of the question unless and until some method could be developed to foil the mines and prevent a dangerous chain-reaction of exploding countermines. After Strauss convened a board to consider the various recommendations and reports on the removal of the Mark VI mines, the board advised using shallow-draft wooden minesweepers (with all metal fittings and fixtures covered and protected) to detonate the mines closest to the surface and then employing larger sweepers to remove the two layers of mines deeper below.
With a plan of attack for clearing the Barrage, the next task for Strauss and his force was to ascertain how many mines remained, if they were still located where they were placed, and in what state they now were. In late December, Lieutenant Noel Davis, Strauss’ Chief of Staff, conducted a test sweep of a small portion of the field, commanding two wooden sailing vessels, Red Fern and Red Rose. Despite careful measures to cover every piece of exposed metal-including nail heads-with wood to protect them, the vessels detonated six mines, confirming both the location and deadliness of the mines.
Although Red Fern and Red Rose handled the test sweep well, Strauss recognized that he would need larger and stronger vessels to tackle the entirety of the Barrage and handle the rough weather and waters of the North Sea. Nevertheless, Strauss found the mine force in something of a bind: large wooden vessels would take too long to build, and the steel Lapwing ships were highly vulnerable. Strauss’ initial solution was to borrow sixty wooden-hulled steam trawlers from the Admiralty once the stormy winter weather had ended (a loan the British were reluctant to grant), but this plan proved unnecessary. One of Strauss’ junior staff officers, Naval Reserve Ensign D. A. Nichols, came up with device that would, by reversing the polarity of the field, prevent the mines from exploding as steel ships passed over them, and thus detonating the mines electrically within a safe radius of the minesweeper.
Obtaining the requisite number of vessels to clear the Northern Barrage during the spring and summer months of 1919 before the stormy months returned proved difficult for Strauss. Early in December 1918, Strauss requested 90 vessels, including 14 of the Lapwing sweepers, be deployed for clearing the Barrage, a plan at which Admiral Benson balked, citing concerns about the need to ensure no mines were left in American coastal waters first. Strauss, with the support of Admiral William S. Sims, Commander, United States Naval Forces Operating in European Waters, continued to push for as many vessels as he could get and, ultimately, thirty-six sweepers total were deployed to assist in clearing the Northern Barrage. In addition to the Lapwing sweepers, the minesweeping force consisted of 20 trawlers, 24 submarine chasers and 9 various support vessels (store ships, barges, an oiler, two repair ships, a salvage ship, and four tugs).
Once the winter storms calmed and the Nichols’ experimental protective equipment could be refined and constructed, on 20 March 1919, Strauss dispatched the minesweeping tugs Patapsco and Patuxent (both part of the original minelaying force) on another test sweep. Nichols’ device worked exceedingly well, although the overall results in terms of number of mines destroyed were less than expected. The test sweep also revealed two problems that would persist throughout the operation. First, mines would become tangled in the sweep wires and detonate before they could be safely discharged on the surface. Secondly, countermining-whereby a deliberately exploded mine caused a chain reaction of explosions of other undetected mines up to one mile away-posed a real danger to the minesweepers that could not be easily prevented, if at all.
Nonetheless, the results of the test sweep proved satisfactory, particularly in terms of confirming the relatively safety in which the minesweepers would be able to clear the mine barrage. Consequently, on 29 April 1919, six sweepers, accompanied by six sub chasers, embarked on the first minesweeping expedition, sweeping the passage area from Inverness, where the Mine Force had been based during the war and the minesweepers were initially located, to Kirkwall, the new base of operations for the sweeping operation. Over the course of two days, the minesweeping detachment, under the commander of Commander Roscoe C. Bulmer, cleared 225 mines, representing roughly twenty-five percent of the mines originally laid in that area.
Over the course of successive operations, Strauss and the American minesweeping force experimented with different tools and methods to mitigate the problems revealed in the test sweeps, reduce the risk of danger to the minesweeping vessels and their crews, and increase the speed and efficiency of each minesweeping operation. The addition of explosive cutters to the wires in front of the underwater kites (a device used to keep the sweep wire at its desired depth) on the second sweeping expedition, for example, reduced accidents by nearly fifty percent.
Despite such improvements in safety and the caution and vigilance of the crews on the minesweepers, the threat of considerable danger remained, and unexpected counter-mining and accidents still claimed their share of victims. On 12 May, the first day of the second sweeping expedition, an unexploded mine that had fouled in Patuxent’s kite detonated unexpectedly after it had been hauled on board damaging the ship and costing the ship’s commanding officer his thumb. Two days later, Bobolink suffered the most devastating casualty of the entire sweeping operation occurred when, similar to the accident that befell Patuxent, a fouled mine exploded near the vessel, killing its commanding officer, Lieutenant Frank Bruce. Although it was saved from sinking, Bobolink was so severely damaged that it remained out of commission for the remainder of the entire mine-clearing mission. The deadliest accident to occur during the sweeping of the Northern Barrage took place on 12 July during the fourth minesweeping expedition, when the trawler Richard Bulkeley struck a mine, sinking in seven minutes and claiming the lives of seven crew members, including its commanding officer.
Accidents and difficulties aside, he sweeping of the Northern Barrage continued apace throughout the summer months. As the ships and crews of the minesweeping force learned from their experiences, they grew more confident and efficient in clearing the mines. By September, the force was prepared to make its seventh, and hopefully, final expedition to clear the last of the American mines. Nevertheless, the fierce storms of the Fall and Winter had already begun, forcing Strauss and his men into a race against time and the elements to clear the final thirty-five percent of mines. On 30 September, however, the minesweeping force completed its mission, leaving no mines left unexploded or unaccounted for.
The clearing of the Northern Barrage represented one of the monumental achievements of the United States Navy both during and after the war. Indeed, “no other operation [was] of such scale and with such an element of danger.” Eighty-four vessels participated in this operation, destroying a total of 20, 711 mines, roughly forty percent of all the mines that made up the barrage. Two officers and nine enlisted men lost their lives, and twenty-three ships were damaged or destroyed. Despite the casualties, the sweeping of the North Sea Mine Barrage was a remarkable feat, particularly in light of the many challenges, problems (both known and unknown), and hazards this mission posed. The navy still had much to do before it could consider its role in European Waters completely finished, but the removal of the “pills of perdition” was a major milestone that brought the United States Naval Forces Operating in European Waters one step closer to this goal.