ROV moves like a snake instead of straight line

We have a ROV (boat) that when we write a mission to it it travels like a snake rather then in straight lines. We get some support to fix but not really sure what was done to correct the issue. So when we have another project 400 km away and load a mission it does the same thing travels like a snake and not in straight lines. Could someone tell me what is going on and how to correct this issue for good or is it something that needs to be done every time we relocate a distance. I know with our drone we always calibrated the compass. This could be the issue here but any help would be welcome.

This is usually just poor tuning of the L1 navigation controller (navigation tuning).
You don’t need to re-calibrate the compass when moving locations. This is what Auto Declination does. Calibration is for local (on vehicle) interference not global (geographic) effects.

Thank you for your comment. We are really new to this, could you send me a screen shot of where we
need to go to correct this problem. Would be much appreciated. We have a project tomorrow and would really like to have a fix if this happens.

Well, its a process:
https://ardupilot.org/rover/docs/rover-tuning-navigation.html
And it assumes you did the lower level tuning 1st.