To cross check means to verify figures or information by using an alternative source, which is what Pieter did by checking the direction with the large oil compass.
Context: "Pieter zoomed in on the gps chart to verify the course and verified the direction by using an alternative source, which was the large oil compass just behind the helm stand."
Hypothesis: Pieter zoomed in on the gps chart to verify the course and cross checked the direction with the large oil compass just behind the helm stand.
Based on the context, is the hypothesis true, false, or unknown?