They thought it was a big ocean.

A British and a French submarine collided in mid ocean. While it's surprising that they accidentally found each other, it's not surprising that neither could detect the other. After all, they're Boomers (ICBM carrying subs), their job is to not be found. But, as I found out once, they are sometimes found.

I was on a patrol in my trusty HH-3F Pelican one day off the coast of San Diego. We spotted a target on radar about 20 miles away and headed towards it. As we got closer, we looked and looked, but couldn't see a vessel. When we got very close, there still wasn't a boat in sight. Finally we saw something in the water right in front of us. "Is that a...periscope?" Yes, it sure was. We came into a hover right next to it. When it turned to where we would be visible, we waved. And it disappeared under the water. You can bet that was embarrassing.

I can imagine the words in the control room.

"$%&!"
"What sir?"
"Uhh...nothing. Just a #$@& Pelican. Down periscope."