The coastline gave some security in Europe until Portuguese and Spanish threw caution to the winds in 15th cent. For Cook with no chronometer in 1770 , Lunar Distances were the go but it kept him busy doing sums. Then it's surprising that Greeks from Egypt went across the Indian Ocean in Roman times. And boats reached the Maldives at 900km W from Sri Lanka , with some 'Indonesians' settling in Maldives. There were no 'Indonesian' trading ports along African coast but they also settled in Madagascar around 8th cent. , 3200km W from Maldives. Portuguese texts report that Javanese also sailed to south Africa and in one case , sailed WSW 4000km into the Atlantic , by count of days. Texts say southern Javanese in 1505 said they had reached the "coldest place on earth", an island with 4 hour day. The Atlantic bearing of WSW would be the way to find the S America coast and then Antarctic peninsula.

At the tip of the peninsula the day is 4 hours in midwinter (as at James Ross island) and ships can't readily go further south then. Days north of there are longer than 4 hours so the geography, ice and sun-elevation are uniquely correct. It suggests they went to check the winter-solstice polar night like Cook doing the transit of Venus.

The first Australians at Macquarie island in 1810 found a "ship of ancient design" (per Aust Antarctic Division). I will give web refs later if the Forum allows it. But it seems that much was happening before Cook rolled into Botany Bay and asked for a drink.

Have you read "1421 When China Discovered the World"

For Cook with no chronometer in 1770 ,

He may not have had a chronometer in 1770, but he certainly had one in 1772

And a beauty is was too.
www.kendallwatches.com/the-world-of-kendall/l-kendall-k1-and-captain-cook

I was under the impression pre accurate time pieces, the MO was to sail along a latitude for X amount of days or until land fall then turn north or south to the desired destination a pilot on board that had knowledge of the coast line was also essential

fouled said..
So the question is , if Cook needed the Lunar Distances and then chronometer , was it likely that a place in Antactica could be reached just by star navigation? A uni prof tells me early ships couldn't return to a given position of longitude without a chronometer.

Long before Lunar Distance calculations, and even in the present day there is DR. The magnetic compass was introduced a thousand years ago; ideas brought back by sailing crews from China, so they were Arabs. The Vikings had a 'sun traverse board' (I think it's called) which was like pocket sundial, with a small gnomon.
With magnetic compasses you can follow directions, you can record directions, and match that with your speed, allowance for drift, etc. So on the vacant expanse of the sea you can plot how far and in which direction. Then when the Portuguese had the monopoly on trade on the west coast (of Africa) instead of heading into the headwinds, they had to tack out and then back in again, zig-zag fashion. Rather than be too close to dangerous shores, you tack on long tacks, and Lo and Behold they discovered Brazil. With repeated trips the estimates of distances become more accurate.
The Arabs crossed from Oman/Yemen and further south all the way to the Indian cities, Sri Lanka, and then further offshore trips to the Spice Islands, etc. The Vikings crossed open oceans, and the English, Bretons and Galicians crossed to the banks of Newfoundland, from which Columbus learned the Viking stories and descriptions of the land just beyond.
A place in Antarctica could just as easily/painstakingly be recorded by these dead reckoning and using the stars. About 40 years ago Dr David Lewis sailed from Tahiti? to NZ just following the setting stars, then the next setting constellation, etc.
And you can do it too.

I imagine that the hour glass along with the log line would have been employed for ded reckoning

shaggybaxter said..
I lived in Greenwich for a couple of years, so on weekends I used to wander down to the Royal Observatory and Maritime Museum and get lost amongst the exhibits, like John Harrison first marine clocks. Incredibly, they had all four iterations (H1 to H4) of Harrison's clocks s and still working, which I found pretty impressive considering the H1 was built in roughly 1735?
You used to wander out of the Royal Observatory just prior to 1pm and find a patch of grass to watch the Time Ball mounted on the roof. At precisely 1pm every day it would reach its zenith then drop, allowing all the ships moored in the lower reaches of the Thames to be able to synchronise their clocks. First used in 1833 and still operating today, the time ball and Harrison's clocks were so instrumental in the successes behind early navigation, it's quite humbling when looking at these pre-that era seafarers achievements and what they managed to do.

Hi Shaggy,
If I remember correctly H1 ,2,3 and 4 all work but only H1 ,2 and 3 are seen working as the wheels
(Cogs) are made of wood and replaced with new ones as they wear out over time whereas H4 is all metal .