Journal of a Seaplane Cruise Around The World
Monday, August 27
Up at 5:15, small breakfast from Mrs. Pettin who stayed up all night with the baby (temp. 102.5° last night, and Hap. Told them to keep him warm, so they simply sat by the fire!) and walked to the pier, where Harold rowed us to the ship. Stowed the luggage away, and laid a new course to Nunarsuit Isl, 60 m. north of Julianehaab. Also calculated distance, which is 515 m. nautical, and local time every 2° long. for taking sun's azimuth and checking compass. Then, in quiet water, we tried a take off: air-speed showed 46, rpm. 1800-1900, the water flew by, the engine smelled hot, we pulled and pushed and shouted, but we did not get on the step, and hence at 8:15 local, 7:25 sun local, 11:15 Greenwich, and 7:15 Rod's time, we are still here floating about the bay.
Figure it this way: we carry 14 hours of gas, so should start that many hours ahead of darkness as to use the gas, case of coming back, i.e., 7:00 a.m. start. The Julianehaab weather is not given until 9:30 (our local) so we cannot know anyway until then how it is there; also had no forecast yesterday - Sunday. So we must get underway and make final decision two hours after leaving land. Still, it should be good by noon in Greenland, if the low moved on normally.
8:47 - Taxiing again. Slight breeze from S.E. This will be 5th or 6th try. Just sighted 2 more porpoise! Must have come in with the tide. Strong tide up here, and we must go against it.
The Flight from Labrador to Greenland; A Review of the Problems of Navigation.
I had been somewhat uncertain about the possibility of recognizing our position on the coast of Greenland, from comparison with the charts which we carried, and it did not seem likely that we would navigate exactly "on course" over 600 miles of open water. To make matters easier therefore the course was laid directly to Julianehaab, but to a headland (Nunarsuit) 60 miles northwest of the village, an intentional error of 6° to the left. Our accuracy of navigation in practice flights had been better than this, and it could be expected that we would at least be correct in turning to the right after reaching the coast, in order to begin the search for Julianehaab.
Shortly after the Labrador Coast had disappeared behind we encountered a low fog, which blanketed the ocean for the next hour of flying. At first we stayed about this in bright sunlight, but later on higher clouds appeared and rain commenced to fall, so that visibility was greatly reduced. It did not seem wise to deviate from the course in search of better conditions so we continued on the course, but descended low to get drift readings from the surface of the water. By flying in fog at 250 feet it was occasionally possible to catch glimpses of the ocean, and Wilson obtained enough observations to correct our course for the sideways shift caused by the wind. Three hours offshore the fog disappeared and we had clear air beneath the clouds the rest of the way.
It is perhaps a worth while digression to mention that aerial navigation over water depends upon pointing the ship in the correct direction, and then changing this direction slightly to overcome the drift to the right or the left which may be given by local movements of the atmosphere. The direction is taken from a magnetic compass during the smoother intervals of flight, and is transferred to a gyroscope which is not affected by irregular movements of the ship. The amount of drift is determined by sighting the surface of the earth through a one-power telescope, which is mounted rigidly through the floor of the ship, and in which are built a set of parallel grid lines. The grid lines are shifted by the observer until the earth appears to pass directly along them, and the correction to the course is taken from a scale on the side of the instrument; a certain number of degrees is added to or subtracted from the compass heading. Once the airplane is driven into or above the clouds however, its tract along the earth becomes uncertain by the amount of the wind drift, which can no longer be determined.
It is occasionally useful to resort to observations of the celestial bodies, which may be employed in two ways: with a bearing place or pelorus the direction of flight can be ascertained, if there are indications that the magnetic compass is unreliable. With the bubble sextant one can locate his position somewhere along a line on the chart; - but is it the line that is established, and not the ship's position on that line. It is evident therefore that celestial observations are useful only at certain times, and that when one must make the choice between flying above clouds to use the sun, or remain underneath to observe the drift, it is wiser to remain below. The "dead reckoning course" can be followed with exceptionally good results.
The ocean crossing was not so dull as one might expect. Wilson kept up a continuous conversation (in code) with the radio operators at Cartwright, Resolution Island, and Julianehaab, and overhead signals from Grierson, the English flier, who was in the vicinity of Gotthaab. Some 300 miles from Greenland messages began to come in from officials at Julianehaab, among them two invitations for dinner, to which we optimistically replied! We also arranged for refueling the ship on arrival. Once, we passed over a dirty looking schooner, ploughing along on its rear and like a balky horse, and it made us appreciate for the first time the roughness of the sea beneath us.
Five hours and forty minutes after leaving Cartwright two icebergs appeared. Three minutes later we became aware of a dark mass ahead, and, as we watched, this gradually resolved itself into the shapes of mountains. At the same time the curtain of clouds terminated overhead, and we came out into warm sunshine, with the magnificent coast of Greenland spread out in front. It was a thrilling sight; nearby, the coastal islands, rising steeply to nearly 4,000 feet; behind and higher, rows of indistinct mountain masses with jagged tops; finally, at great distance, a soft mantle of white, the unique Greenland ice cap.
The problem of identifying our position was immediately at hand. Directional radio would have been of great help, but our instrument had never before given a satisfactory operation, and it seemed hopeless to experiment now. Had the hour been nearer to noon, a sextant line-of-position would have intersected the coast and afforded a definite fix, but the sun was now astern and quite useless. While examining the land we climbed to 5,000 feet and turned to the right to follow the coast toward Cape Farewell. There appeared to be no ready means of identifying either the islands or the fjords; a great many of both were seen, and they failed to fit any groups shown on the charts. One bold headland stood further out to sea than the others, and this may have been Nunarsuit, but we had not expected it to be so isolated. We saw no towns.
Exact identification was made finally by ascertaining the direction of the coastline, after setting the gyroscope from the sun's azimuth; the true bearing proved to be 102° and on the chart this line fitted the coast only between Nunarsuit and Julianehaab. Calculation now showed that landfall had been made 25 miles to the left of the course near Ivigtut, and that we were in fact proceeding toward our goal.