Theres just been a post about altitude.

Anyway Debs was saying a minute or two ago.

We must go twice as far as the chart says, going up and down all the time. So how much difference does it make. The wibbly wobbly way,has to be nearly twice as far as dead flat.

Is this why the GPS never agrees with the log, even more than the tidal situation. Or does it compensate for it in some way.

It's a gludy sort of question, sorry.