Thanks everyone. The paper was onion skin, and is very creased and yellowed, and the pencil lines were all quite faded. I had to process them all in Photoshop for them to be legible. I have hundreds of these old blueprints, I'm posting one of the old drawings a day to http://starshipdesigns.tumblr.com/
. Check them out for a taste of '70s fan nostalgia. Maybe sometime soon I'll pull out the old t-square and angles again and see if the old version of myself can do better than my kid self.
Very fun to look at... It's funny how much they Remind me of my old drawings from the late 70s and onward. I had most of mine until just a few years ago when there was a flood at my grandparent's.