Reach in the inspection port with a sponge and get out as much water as you can that way. Blowing in a single port with a shop-vac will apply too much pressure and be bad for the hull. But if you have two ports in a hull, open both and blow in one. That will dry out the hull quickly.
If the boat has an inspection port(s), open them up and put the hull in a closed room/garage with a dehumidifier. It will dry right out and lighten right up.
tip the hulls way up to drain most of the water, then put them in the sun and open up the inspection ports, the hull will heat up enough to evaporate the remaining water slowly. Another method I used to dry the inside for a repair was put a drop light in there for about 1/2hr and that did the trick. You can put some paper towels inside the hull as well to suck up moisture.