My AC unit is one that blows from the outside in instead of going to a blower inside the house. All the ductwork is in the crawlspace of the house and the ductwork is starting to leak. Can you give me an idea of how to fix it?

Does a crawlspace need more then one vent? Or does it need any at all?

"Starting to leak"-Air leakage, water dripping? Give us better detail