[tbontob]

Originally posted by Suicide Junkie:
Designs that you have marked obsolete will be deleted from your list of ships when all of the following are true:

1) There are no surviving ships of that class. This includes ships that have been captured or gifted to an alien race.
2) You are not building more of those ships.
3) The year is xxxx.9
4) You have just pressed the end turn button to take you to year xxxx.0

Your points #3 and #4 clears up a question in my mind as to when obsolete ships were deleted. Before your explanation, it just seemed random.