“Curtin, we’re in for some work to-night, or else I have an attack of nerves. I feel it,” said Dave without taking his eyes from observation of the sea.

“So do I. Queer how a fellow can sense danger when he neither can hear, see, feel nor smell it,” said Mr. Curtin.

“Submarine hunting is hard on the nerves, but it’s worth while,” returned Dave. “I think that must be what makes life on a destroyer so attractive to us. It is the real sporting game. I—What’s that?”

“Yes, it’s——”

“Sh-h-h!” Dave suddenly stiffened, bringing his glasses quickly to his eyes. “Bow watch there, did you hail?” he demanded in a low, sharp voice.

“Aye, aye, sir,” came the prompt reply, also pitched in a low tone, though full of repressed excitement.

Whatever wind there had been in the cloud Dave had observed to the northeast, had passed. Only the gentlest of breezes blew, though the sky remained overcast, giving an almost ink-black night—a night for dark deeds.

So long did the “Logan” drift that probably every wakeful soul on board felt irritated by the monotony. Suddenly Dave stiffened, bringing his glass quickly to his eyes.

“Sounds and looks like a craft two points off starboard and about half a mile away, sir,” reported the bow watch.

“Aye,” Dave responded. “I see it. Mr. Curtin, pass the word for all hands to quarters.”