I’m new to the world of ROV’s and after many days of building we finally got our Blue ROV in the water. Unfortunately when we try to make it go straight it seems to want to spin in circles, in the stablize mode it does flips. It is happy to go left or right when we direct it to and we were sure to check that all the motors were spinning in the correct direction.
Does anyone have any suggestions on what I should look at first to try to fix this issue?
Many thanks!
MC
Hi @Mary-Claire, congratulations on completing your ROV build! 
If this is in manual mode, that sounds likely to be a motor configuration issue - either due to one or more thrusters with reversed directions, or connected to the wrong input. I’d suggest you use the QGroundControl Motors Setup Page to confirm that each control slider corresponds to the correct thruster in the frame, and once that’s confirmed you can run the automatic motor direction detection to fix the control for any of the thrusters that have their coils reversed.
It’s also worth checking that all the thrusters are oriented correctly, have the expected clockwise or counter-clockwise propeller, and can be spun freely by hand while off (ie don’t have anything stuck in them).
I’m assuming this is due to the same issue as above, but it could also conceivably be due to an uncalibrated or faulty sensor. It may be worth using the Sensors Setup Page to calibrate the sensors