The barrage was completed October 26th, almost coincident with Germany's recall of its U-boats, which practically ended submarine warfare. Some of those recalled did not reach these waters until the armistice had been signed, hostilities were over, and they were immune from attack. Some "ran" the barrage, and several met the fate of the U-156, one of the undersea cruisers which operated off our own coasts. Attempting to get through the barrier, she struck a mine and went down. So far as known, only 21 of her crew were saved. The Northern Barrage cost us approximately $80,000,000. Shipping sunk by submarines averaged, for a long period, over $70,000,000 a month, at times ran over $80,000,000, in actual monetary value, not counting the resultant military effect of its loss. Admiral Sims estimates that the war cost the Allies $100,000,000 a day. Thus, if the Northern Barrage shortened the war one day, it more than repaid its cost. Our mining projects were not confined to the North Sea. Plans had been accepted and mines were in process of manufacture for a like barrage across the Straits of Otranto, from Brindisi, the heel of Italy, to Saseno Island. This would have effectually shut up German and Austrian submarines in the Adriatic. We had also agreed to undertake to provide and lay 26,800 mines for a barrage in the Aegean Sea from Euboea Island to Cape Kanaptitza, except for the part resting on Turkish territorial waters, which was to be established by Great Britain, since the United States was not at war with Turkey. The armistice made these barrages unnecessary. But our mining operations were by no means concluded with the cessation of hostilities. Clearing the seas was our next duty, for navigation would not be safe until the many thousands of mines were removed. This work was divided among the various nations. The United States volunteered to remove all the mines we had laid. Admiral Strauss, in charge of these operations, had his base at Kirkwall, and his force comprised 34 mine-sweepers, 24 sub-chasers, two tugs, two tenders and 20 British trawlers, which were also manned by U. S. naval personnel: Repair Ships and Force Auxiliaries--_Black Hawk_ (flagship); _Panther_, _Seneca_, _Chesapeake_, _Aspenleaf_, _Crenella_, and the British vessels _Hickorol_, _Petronel_ and _Hopkiln_. Submarine Chasers--Numbers 37, 38, 40, 44, 45, 46, 47, 48, 95, 110, 164, 178, 181, 182, 206, 207, 208, 254, 256, 259, 272, 329, 354, and 356. Mine-Sweepers--_Auk_, _Avocet_, _Bobolink_, _Chewink_, _Cormorant_, _Curlew_, _Eider_, _Falcon_, _Finch_, _Flamingo_, _Grebe_, _Heron_, _Kingfisher_, _Lapwing_, _Lark_, _Mallard_, _Oriole_, _Osprey_, _Pelican_, _Penguin_, _Quail_, _Rail_, _Robin_, _Sanderling_, _Seagull_, _Swallow_, _Swan_, _Tanager_, _Teal_, _Thrush_, _Turkey_, _Whippoorwill_, _Widgeon_, _Woodcock_, _Patapsco_, _Patuxent_.