AT 7:40 P.M., TUESDAY, SCHWIEGER AT LAST SIGHTED the coast of Ireland. A lighthouse lay on the horizon, barely visible in the rising mist.
The day had been a disappointment. Strong swells had made the going uncomfortable for the crew below, and Schwieger had found no targets worthy of attack. An armed trawler briefly had come into view, but he realized its draft was so shallow that a torpedo would likely run underneath its keel. Visibility had been poor for most of the day, though by evening it improved to the point where he could see distant objects. The gathering haze, however, foretold a night of fog.
Fifteen minutes later, a steamship appeared, heading in U-20’s direction. It was still far off but looked to be a vessel of significant tonnage. Schwieger ordered a dive to periscope depth and prepared his attack. He placed U-20 at a 90-degree angle to the ship’s course, to set up what he called a “clean bow shot,” and once again selected a bronze torpedo.
As the ship approached, however, it seemed to shrink in size. Something about the fading light and mist had produced an optical illusion that made the vessel at first look large, but the closer it got, the smaller it got. Schwieger estimated its tonnage at a mere 1,500 tons. Still, it was something. He maneuvered so that when the ship’s course intersected his, he would be just 300 meters away. The target was still a mile off.
And then, as he watched through the periscope, the ship sheered from its course. At that distance, there was no chance for him to catch up.
Even in the spare prose of his log, Schwieger’s frustration was evident. “It was impossible that the steamer could have seen us,” he wrote. He identified the ship as a Swedish vessel, the Hibernia, “with neutral signs, without flag.”
Schwieger brought U-20 back to the surface, and continued south, through a night he described as being exceptionally dark.