New build rover(boat) wobble

We recently completed our new rebuild of our boat got the steering and the throttle to work. We took it out to run a mission and we get a
Terrible wobble. Tried Randy’s tuning instructions but with no success. I will post a video of the boat shortly. Any suggestions or help would be appreciated.
https://drive.google.com/file/d/15b22Bwd9KMHixqw4RTLP-rG9aTpiUVDx/view?usp=sharing

We have just faced the same problem this week and it solved trying with reversing the servo output