Very cool. Having done a little navigation myself I am simply astounded at that feat of seamanship - these guys had no means of determining longitude and they still managed to end up pretty much where they intended. Once might be accident, twice luck, but four times is just amazing.
They used a knotted rope to determine their speed at any given moment and so were able to roughly calculate distance gone.....................
I'm particularly impressed with Wm Bligh's awesome trek taking the small boat he was kicked onto after the mutiny of The Bounty.
from wiki: The mutineers provided Bligh and eighteen loyal crewmen with a 23-foot (7 m) launch (so heavily loaded that the gunwales were only a few inches above the water). They were allowed four cutlasses, food and water for perhaps a week, a quadrant and a compass, but no charts, or Marine chronometer. Most of these were obtained by the clerk, Mr. Samuel, who acted with great calm and resolution, despite threats from the mutineers.
The launch could not hold all the loyal crew members, so four were detained on the Bounty for their useful skills; they were later released in Tahiti.
Tahiti was upwind from Bligh's initial position, and was the obvious destination of the mutineers. Many of the loyalists claimed to have heard the mutineers cry "Huzzah for Otaheite!" as the Bounty pulled away.
Timor was the nearest European outpost, 3,618 miles away. Bligh and his crew first made for Tofua, only a few leagues distant, to obtain supplies. However, they were attacked by hostile natives and John Norton, a quartermaster, was killed.[4] Fleeing from Tofua, Bligh did not dare to stop at the next islands (the Fiji islands), as he had no weapons for defence and expected hostile receptions. He did, however, make use of a small notebook to sketch a rough map of his discoveries.
Thus, he undertook the seemingly impossible 3,618 nautical miles (6,701 km; 4,164 mi) voyage to Timor, the nearest European settlement. In this remarkable act of seamanship, Bligh succeeded in reaching Timor after a 47-day voyage, the only casualty being the crewman killed on Tofua.