Might be better to think of the truck as the vehicle that allows you and your crew to carry all the supplies such as food, water, fuel, clothes, etc that you will need during your rescue operations, all while towing the boat(s) needed for the actual rescues. If that truck and its fording gear can get you a few miles closer to where the boats are needed, it saves precious minutes on each round trip the boat has to make.
Be sure to consider the fording height of the boat trailer as well. Might be bad if the truck in doing fine in 18" of water but the boat is lifting the 8" high trailer off the road.