Questions re: Underbelly, A.C., Tub replacement, etc.

[Hot Florida]

I am moving into a 1978 Modular home owned by my Daughter for 17 yrs. as a rental. Till now, all that had been done was roof and A.C. work. She recently had a real tub put in after replacing floor under it with plywood. I am concerned about the weight when filled with water. Any thoughts?
Also, the repairman could stand on dirt (under the home) while adjusting the tub. Isn't there supposed to be an Underbelly? (Whatever that is).
If he was standing on dirt, that means there is no plastic moisture barrier? The house is on blocks, not concrete slab.
Then the A.C., the last renters complained it was too hot in there. I turned on the A.C., and the fan you can see, stopped turning after about 30 min. The fan or motor that is housed (that you can't see) was still running. Is that normal? It had not reached the 75 degrees I had set the theromstat at.
Thank you for any explanations and tips.

[admin]

I would not worry too much about the tub... the floor should hold it and the water with no problems. Most manufactured home floors are framed just like those on any framed home.

There should be a plastic type barrier under the floor which serves to hold the floor insulation place and prevent moisture from entering the home from below.

The fan on the AC will stop when it has reached the temp that it is set for. Your thermostat my need to be recalibrated. You probably need to call in an AC repair guy to check this out.