Joe wrote:
"One of the tests involves sitting at the chart table, with the ports
blacked out, and predicting your position to within a few metres.

In other words, you have to sail (and navigate) the boat "blind".

No external imput at all.

How can this be done?

If your starting position is known, one of those inertial gyroscope thingies
might work.


--
Wally
www.art-gallery.myby.co.uk