Bill
Like 99.99% of all multi-channel radio sets the T5 was designed for model aircraft. The fifth channel is intended for either rectracting the undercarriage or lowering flaps, neither of which require anything but Up or Down. On a model boat you can use it to switch a lighting circuit or raise and lower a door, loading deck, boat etc.
Perhaps if you tell us exactly what you wish to control with the radio in addition to steering and motor speed then someone might be able to suggest a way of doing it. I know that you have five channels available and you want to raise and lower the bridge as well as switching some lights. That's dead easy even with just four channels, so what else is it that's creating the problem?
DM