I'm assuming the crawl is enclosed. (If not, write back ...) No, don't add any fans or anything. The introduction of potentially warm, moist air into a cool crawlspace will create even MORE moisture and condensation. You solution may be simple.
You mentioned that the crawl got flooded. If it's a one-time flood, maybe you can't do anything permanent to 'fix' the problem (unless you build a moat or something around your home.) However, if it's a 'slooooow fill', then perhaps building a Dry Well with a Sump Pump is the answer. If the water is from the rain, then during the next storm, ... Put your boots and raincoat on and grab an umbrella (assuming no lightening) and do a COMPLETE perimeter walk around the ENTIRE house. Look UP as well as DOWN to see 1) where the water is coming from, and 2) where it's going. If you have gutters that are leaking, fix/replace them. If you have clogged gutters, clear them. If you have clogged OR missing downspouts, clear them too. If you DON'T have gutters where water is RUNNING off the roof, install gutters and downspouts at those locations. If water is running OVER or BEHIND your gutters, they need to be rehung. If you're downspout water is 'dumping' at the foundation, get 3' extensions (minimum), and put them on. If you have water that happens to 'run' back TOWARDS the foundation, you need to re-grade.
In short, you need to take all possible measures to keep water AWAY from the foundation. After doing all this, and you still get water under there in a rain, then it's time for a pit and a pump. Remember, MAKE SURE that the discharge water from the pump doesn't run BACK towards the house! (The pump might run a LOT more than it should.) Yes, you need to replace the insulation. You will need 'hangers' to hold the new insulation up (since I figure your current insulation is 'original'.) You can even hang some chicken wire under the joists to 'hold up' the new insulation (kraft side UP.) Use a good staple gun w/at least 3/4" staples. Or, nail in some 1" roofing nails and 'string' some wire or string back and forth to create a 'net' to hold up the insulation.
If I'm way off on my assumptions whereas my 'ideas' don't make sense, then come back w/more details. My best to ya and hope this helps.