To Mr Varley I doff my hat.
He summarises matters that
Exceed all learning ever mine,
Since Galileo, Maskelyne…… etc!
My apologies, Chris, - Any familiarity of mine with electronic navigation came to its end in 1988.
As to ECDIS?:-
Early Closing Day Is Saturday?
Every Convivial Drink is Special?
EC Directives Invite Screams?
Has anybody yet solved the problem of what happens when the electrics pack up?
Speaking of Ushant, I have a vivid recollection of boarding a small Danish ship off Point Lynas one winter morning - and learning that she had lost all of her electronic navigation equipment and her magnetic compass too, heading north in a violent Biscay storm. She had come from Punta Arenas, of all places. A thing which did survive was his radio reception - and a key aid to navigation became the weather forecaste. The master's own experience of reading the sea and sky (and matching it up to the forecaste weather) were enough to enable him to find his way up St George's Channel. We dismiss the Mark-one Eyeball at our own peril!