How to enable servo output on Pixhawk 3 Pro

Hi. I’m turning my sea kayak into a USV Hydrographic Survey Boat. The autopilot is a Pixhawk 3 Pro. I have a PC onboard running Hypack to collect the hydrographic data. I have used MissionPlanner to calibrate the radio (Taranis X9D Plus/X8R). I have calibrated the radio channels, and have channel1 enabled as Rudder and channel 3 as Throttle (in Config/Tuning/Standard Params). But when I go to Initial Setup/Servo Output, nothing happens.

How do I enable the Servo Outputs ?

Best Regards

What firmware are you using?

Hi. I have found and downloaded this APMrover2-v4pro.px4

Ah. Ok.
A couple of options. To use that firmware, have a read of then wander over to for assistance if you need it.
Alternatively, you could try px4 and set up as a rover (look in @Chris_Anderson is pretty involved with rovers so may be able to advise a bit more specifically (sorry Chris) if one has an advantage over the other. Surface vehicles (rover and boats) are probably the least mature (and hence least documented) in both codebases.