The German Sub That Sank Itself by Flushing the Toilet The U-1206 was a Type VIIC submarine, fitted with a new high-pressure toilet designed for use at great depths. This system was so complex it required a specially trained technician to operate its sequence of valves. During its first combat patrol, a mistake in this procedure unleashed a torrent of seawater and waste into the forward section of the sub. The immediate flooding was not the fatal blow; the disaster escalated when the water casca