In really high seas one night, I was setting up an intercept on a Large Modern Tanker. I was stoked about the heavy tonnage headed my way, only 3000 yards away, steady at 9 knots. The seas were pretty high, and it was pretty dark, so I left my periscope up (this was also my first planned intercept, so I was not confident of my measurements).
Suddenly, the ship slows. 6 knots. Has it seen me? Surely not, we're 3000 yards away. And wouldn't he speed up if he saw a periscope staring back at him from the depths? No mind, keep watching. Legion's noob guide says to be patient, I'm not going to ruin my shot at... looks like 1200 yards because of impatience. 4 knots now, something odd is going on. She's stopped at 2600 yards. Flood tube 1, just in case. "Enemy Unit Destroyed!" What!? *Checks ships log* I didn't get credit for it, darn it. I had him! This close, THIIIIS close!
I can only assume that I watched him founder in high seas, presumably the waves breaking over his deck flooded his forward compartments (They didn't know how to batten down the hatches, I guess), as he went down by the bow.
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*While troubleshooting a printer at work
Me: "Do you want me to run the copies through again?"
Boss: "Hold on, let me go get the alcohol first.
Me: