How Did Sailors Know Where They Were? (No GPS, No Map Apps)

Six weeks at sea, no land in sight, rocks somewhere ahead — and no GPS, no radio, no little blue dot. So how did sailors on wooden ships know where they were? In this episode: dead reckoning and the log line (and why ships and planes still measure speed in knots), the traverse board, the leadsman's lead line with sticky tallow on the bottom (and where Mark Twain got his name), latitude from the noon Sun and the Pole Star, the cross-staff, backstaff, octant and sextant, "running down the latitude" — and the hard half: longitude. The 1707 Scilly disaster, Anson's missing island, the Longitude Act's £20,000 prize, the lunar distance method, John Harrison's H4 sea watch, Captain Cook's "trusty friend the Watch", the Bounty mutineers who took K2, and the Greenwich time ball that still drops every day at one o'clock. 0:00 Where are we? 0:54 Dead reckoning 1:10 The log: why speed is in knots 1:55 The traverse board 2:27 The lead line 3:01 Mark Twain 3:15 The secret in the tallow 3:43 Latitude: the easy half 4:05 Cross-staff, backstaff, octant, sextant 4:27 Running down the latitude 4:54 Why longitude was so hard 5:40 1707: disaster at the Isles of Scilly 6:12 Anson and the missing island 6:39 The Longitude Act: £20,000 6:56 The lunar distance method 7:25 John Harrison, the carpenter 7:45 H4 8:06 The fight for the prize 8:28 Captain Cook's watch 8:54 K2 and the Bounty mutiny 9:22 The Greenwich time ball 9:44 1884: longitude zero 9:56 So how did sailors know? Next episode: crossing the equator — and why King Neptune came aboard. #history #sailors #navalhistory