In one game I had it give me dozens (maybe hundreds, I didn't count) of covette class precursor ships. They all sucked, have something like 2 hp beam damage. I started trying to sell them... select, sell, confirm, select, sell, confirm... after 10 mins or so I gave up and just loaded the last save game.
A much easier way to get rid of them, and it will gain you some brownie points, is to simply give them away.
Since they didn't cost you anything in the first place... and they will improve your relations with anyone you give them to...
Seems like a win-win situation.
And if you give them to a race that you will be going to war with, you stick them with all those little 'nits for ships'.