how do navigators use to help plot their course?

I can't find that question either Nick!

For readings on the art of wayfinding, see the PVS website:

http://pvs.kcc.hawaii.edu/navigate/wayfind.html

the time table shows that the leg from Okinawa to Kumamoto is on a bearing of 309 degrees. Should be about 30 degrees or NNE?

ooops. that was an old bearing from Palau to Okinawa. I calculated NNE 21 degrees from Okinawa to Kumamoto. thanks for the correction.