If your lifeboat is without a navigator, these directions are for you. There is nothing difficult about them. They are as simple as the directions for a child's game. But they will provide you with the key to your own rescue.
Before leaving your home port, purchase a U.S. Hydrographic Office "Pilot Chart" covering the area of your ship's route. Pilot Charts cost ten cents a sheet, and are obtainable at any nautical store. If your are a soldier or sailor, and consequently do not know your route or destination, we suggest that you buy for sixty cents the six sections taking in the entire world.
Disregard the printed statement that the chart is not to be used for navigation. For your purposes it is entirely adequate. During the nineteen days in the Robin Moor lifeboat, Banigan daily plotted his position on a Pilot Chart.
If you have no chart, and do not know of any islands North or South of you, set your course as close to due East or due West as the winds will permit, and eventually you will sight land.
With a Pilot Chart and knowledge of your approximate position, you can plot the track or route you should take, simply by observing the nearest point of land from you.
Whether the average winds are in your favor can be readily seen by the wind roses on the chart along your chosen track. The chart provides adequate instructions regarding the wind roses.
If you are an untrained man, do not concern yourself with the set of the current. Your guess as to allowance will undoubtedly be out of proportion.
Obtain your true course -- the one you intend to steer by -- in this simple manner:
Note the compass rose -- the circle on the chart that is graduated from 0 to 360 degrees.
Take two stick or pieces of cardboard.Lay one on the proposed track.
Lay the second stick across the center of the compass rose parallel to the first stick. Use the stick in the same way you would use a ruler.
Read off the course indicated by the stick on the compass rose in the direction of the proposed track.
Note the lines of variation plainly indicated as to the amount and direction, East or West.Variation is the difference between the true or geographical North and the magnetic North.
NOTE ON CHART (see opposite page)
On the opposite page is reproduced the photograph of a section of the Pilot Chart on which John J. Banigan plotted the noon positions of his Robin Moor lifeboat. The oblique line shows the robin Moor's course and noon positions east of the Great Circle track, from May 19th, 1941, until the vessel was torpedoed and sunk by a Nazi U-boat on the morning of May 21st, 0805 Greenwich time. The jagged line, running from right to left, shows the route of Banigan's lifeboat, from setting sail on May 22nd to 10:00 the night of June 8th, when the eleven men were picked up by the Lloyd Brasileiro line Osario, Lat. 0°46'N, Long. 37°37W. Note that the boat was about 119 miles from St. Paul Rocks on May 27th, when it reached the southernmost limit of the NE trades. Note the two periods of doldrums -- calms -- from May 29th to June 1st and from June 4th to June 6th. Note that no positions were plotted for May 31st and June 3rd when overcast skies prevented the taking of sights. These positions were checked back in banigan's Work Book by Captain W.L. Pereira of the Osario. Navigators attempting to take sights in lifeboats have complained that they were unable to find the horizon. These checked positions offer documentary evidence that by standing on a thwart, supported by crewmen and resting against a makeshift rail, a mate should experience no great difficulty in making use of his sextant.
Banigan's Pilot chart (Photograph by Edward V. Banigan)
But don't worry your head about what variation is. Concern yourself merely with what you have to do about it.
Variation represents an error which you must correct.
If it is stated on the Pilot Chart that the variation is West -- add the amount of variation to the course indicated by the stick on the compass rose. If the variation is East -- subtract.
The answer is the course to steer.
So long as the sail is kept full, a lifeboat rigged with a dipping lug sail will average between 3 to 4 knots in a moderate breeze. Gauging your speed by this, and mindful of the chart's scale of measurements, you can plot your position day by day.
The scale of latitude is used for measuring distances.
You will find this scale on the right- and left-hand sides of the chart. One degree equals 60 miles or minutes. The scale is graduated in 6 parts of 10 minutes each.
Always measure off distance near your parallel of latitude.
The scale of longitude is graduated in the same way as the scale of latitude. But never use the scale of longitude to measure your distance.
When there is any shift in the wind which may require a change in course, you should make
each change, if possible, in the general direction of your proposed track.
We have made no attempt to teach the elements of navigation, but we have presented a working plan which will help you to reach land or the steamer tracks where you have a chance of being picked up.
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