The captain came to the bridge and just stood there not saying much, and the OOD just made small talk with him. All of a sudden there came a terrific bang, jarring, vibrating noise from the sail and superstructure and the boat shook and trembled. 

We were all scared and were wondering what had happened. Words of wisdom like "we hit a submerged submarine, we hit a whale, we've had an explosion somewhere, or hit underdermined sea debris" filled the air. The captain just stood there, doing nothing. 

The OOD sprang into action, wounded the collision alarm, set condition Baker, all stop, all compartments report damage, etc.. Expletives filled the air, and I was seriously considering jumping overboard! The boat just kept shaking and vibrating and losing way. 

After a time the OOD was assured by reports that all below was OK and that we had power, control, steerageway, no apparent damage or flooding or anything. Here's what had happened. 

The CO had gone to maneuvering and told them to give him a couple of minutes then put the boat into all back full, and then went to the bridge to see what was going to happen. We began suspecting something was funny when he just stood there and watched it all without saying a word. 

Later on the OOD was mad because he had been had and we were relieved that we didn't have to jump overboard or sink. Of course our language was salty and appropriate to the occasion, as I have neither seen nor heard anyone of any service who could use words to express themselves like a sailor. We can all be proud of our heritage. Diesel Boats Forever!