I just launched a big attack to conquer an enemy planet. I was sure to have enough minesweepers with me, but out of stupidity I had built minelayer components on most of them.
I lost 10 ships, most others were crippled. My only luck was, I could still conquer the planet, and it had a space yard on it.

My enemy now either thinks I'm a complete idiot, or that I have mined his territory big time.
Gorgo