Compass error with our ROV (boat)

Hello i am new to the group and need some help.
We have a ROV Boat that we use for mapping of water bodies. it appears that every time we move to a different location we have issues with the boat after loading a mission from Mission Planer and start the mission the boat travels like a snake rather in straight lines. We have had some support on this to correct the problem but need to figure it out for ourselves why this happens every time. We think it is a compass error. We have drones that we always calibrate the compass so I don’t think this is any different.
If anyone can help us with this or lead us in the right direction we would really appreciate it.

Hi @fisheye amd welcome.
You might have better luck on the Mission Planner forum: