Originally Posted by GeorgeB
I could have sworn that calculating longitude at sea wasn’t possible until the advent of accurate chronometers in the 1800’s. A while back, I read the account of the whale ship Essex, and in it, most captains couldn’t calculate longitude until their second or third voyages (if at all) and some captains left on their first voyage without the skills to accurately determine latitude. No real knowledge of global weather or current patterns, primitive navigation tools, quill pen and long division for calculations… Yes, I think that 17th and 18th century navigation is fascinating.
Well.. If that were true, Captain Cook, for example, would never have found Tahiti (and he wasn't the first there) and could never have accurately charted New Zealand and the east coast of Oz - in 1770/1771.
You probably quite correct that most captains couldn't calculate longitude correctly and hence approached a lee shore at their peril - but that's only because they couldn't do the math, not because the knowledge wasn't there.
It's extraordinarily easy for us thesedays to just decide "I'm going to take a few weeks off and sail across the Pacific", forgetting just how much heavy duty research over hundreds of years has gone into making it a safe trip.