We had advanced a hundred yards, perhaps, when our first danger confronted us. Just ahead was a sharp right-angle turn in the tunnel. I could see the river's flotsam hurtling against the rocky wall upon the left as it was driven on by the mighty current, and I feared for the safety of the U-33 in making so sharp a turn under such adverse conditions; but there was nothing for it but to try. I didn't warn my fellows of the danger--it could have but caused them useless apprehension, for if we were to be smashed against the rocky wall, no power on earth could avert the quick end that would come to us. I gave the command full speed ahead and went charging toward the menace. I was forced to approach the dangerous left-hand wall in order to make the turn, and I depended upon the power of the motors to carry us through the surging waters in safety.