So great is the danger from mines, unless they are watched and tackled the whole time, that thousands of mine-sweeping vessels were always at work, manned by British fishermen who had been handling gigantic nets and mile-long steel hawsers (ropes) ever since they had gone afloat as boys. These North Sea fishermen, in whom the Viking blood runs strong, had always put in eleven months sea time every year of their lives. So storm and fog and clammy numbing cold had no terrors for them as they worked their "sweepers" to and fro, fishing for the deadly mines. Sometimes, for all their skill and care, a mine would foul their tackle and blow them to pieces. But usually they could "gentle" a mine to the surface and set it off by rifle shots at a safe distance. Sometimes, however, a hitch would happen and the mine would come close alongside. Once a mine actually came aboard, caught fast in the tackle. The skipper (captain) ordered all hands into the boats, and then himself cut it clear after a whole hour's work, during which one false touch or even the slightest jolt would have blown his ship to smithereens. The wonder of it is that more men were not killed in keeping the seaways so carefully swept, night and day, all the year round, for tens of thousands of miles, during the fifty-one months of the war. [Illustration: Minesweeper at work.] Still more dangerous was the fishing for those vilest of devil-fish, the German submarines. The fishermen "shot" enormous steel nets just as you shoot a fishing net, letting them hang a bit slack so as to be the more entangling. Then, just as you feel your rod quiver when a fish takes your fly, so these anglers for Germans would feel the quiver from a nosing submarine caught in the toils. Very few submarines ever escaped; for the slack of the waving net was apt to foul the screw, and there they were held till the last struggle ceased and the last man was smothered inside.