Any idea how to get underneath a bathtub in a mobile home?

i've got a 1990 Fleetwood with a garden tub that has a crack in it.I'm going to use Marine Tex to repair the crack, but i would like to repair on the top and bottom, but i can't figure out how to get to the underside of the tub. Has anybody had this problem before that can give me some advice? any help at all would be welcome. Thanks!!