At 3 o’clock I got four more shots at the sun, now dead ahead, and behind the petrol tank between the top wings. I had to use the sextant fast, setting the seaplane into a dive so as to get the sun above the tank with the horizon below the wing beside the motor, and immediately I had the sun touching the horizon in the sextant I jogged back the control to climb, while I recorded the sextant, watch and altimeter readings. My handling of the Moth was already becoming automatic – I was getting the feel of her as a seaplane. I worked fast at the computing, and made it 127 miles from the turn-off point.
My brain felt over-stretched.
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With the two sets of drift readings, plotting them, and sending a wireless message every hour, I was being too hard-pressed. It would be no use getting an accurate position if I let the top tank run out of petrol, or something equally stupid. Suddenly I thought I could hear a muffled knocking in the motor; it must be that cursed No. 3 cylinder again.
If the motor failed, I must turn right about immediately to face into wind before the seaplane hit the water. I knew that I must not let myself get hustled, and I decided to cut out the next set of drift observations, and think instead. I relaxed for a while, and then reviewed everything: fuel gauge, oil pressure, engine revs, height, compass, chart. I was getting near the turn-off point. With the big lift I’d had from the tail wind, I might be ready to turn off earlier than anticipated, so I must make a fresh set of calculations for 4 o’clock instead of 5 o’clock. And I had to hurry, for I could see some fleecy clouds ahead, though not thick, thank heaven.
I worked out in advance the sun’s position, and how far I should be from it at 4 o’clock so that when the moment arrived I should have only to take the sights, and the results would tell me at once how far I was from where I expected to be. I was getting intensely excited, but it did me good by keying me up for the vital work ahead. At 4 o’clock I took four shots from between 100 and 150 feet up, turning the seaplane in a steep bank to the right, so as to catch the sun abeam between the wings. After each shot I turned on course again, while writing down the sextant and watch readings. I quickly plotted the result, which showed my dead reckoning to be 19 miles out. There must have been a mistake somewhere: where? If there was one mistake, why wouldn’t there be several? (My outboard air-speed indicator was over-reading by 5mph which had built up to 20 miles in the four hours of flying. )
But there was no time to worry about that; I had to put my faith in the sextant. According to that, I was only 45 miles short of the turn-off point. I still had the same strong tail wind, and as a result I was travelling faster than I had expected. I cut the seaplane’s speed back to 60mph, so that I should have half an hour before reaching the turn-off point, and hurriedly computed the work for another sextant sight at the end of that half hour. It would be the critical moment of the flight, for when I turned, it must be exactly towards the island.