Suddenly all were startled by a cry from their host.
“Go ahead! go ahead!” he shouted down the hatchway. “That other fellow has launched a torpedo at us!”
“Let go the line, then!” urged Ned. “We’ll have to run for it! Full speed, Jimmie!” he added.
Mackinder was casting off the hawser with rapid motions. Jimmie, in response to Ned’s command, threw the switch over. The “U-13” began to gather headway.
All were startled to hear the report of a cannon shot. This was followed almost instantly by a shriek from the man on deck.
“Mackinder’s hit!” gasped Ned, turning a blanched face to his chums. “What shall we do?”
As if in answer to his query, the voice of Mackinder reached the ears of the lads.
“Bring an axe!” he shouted. “I’m fast in the bight!”
Wrenching an axe from its pocket on the bulkhead, Ned sprang up the ladder at his best speed. On deck he found Mackinder caught in a bight of the hawser by which the other vessel had been towed. His leg was jammed against the fairleader. Only one glance was required to show the boy that serious injury had been done.
Without waiting for words, the lad stepped to the side of the fallen man. Swinging his axe quickly, he struck at the taut bond of hemp. A shower of sparks followed the ringing thud of the axe upon the steel deck.