you can synchronize GoPro with the phone via. Wi-Fi just before the race. GoPro loosing 20 sec per day, so you will need to re-sync each time your going out on the water. The other option is to use geovids time offset function and adjust your video timing. The best way to do it is to find a tack on the GPS track and stop the replay as soon as the boat is head to wind (use the VMG dispay). Move the video footage back or forward as needed to align the video with the track. If you are tacking port to starboard and the video is still on port move it forward and if the video on Starboard move it backward.