There seems to be a widespread opinion in naval circles that officers of the U. S. Merchant Marine have failed to avail themselves of the new and up-to-date methods of seamanship and navigation. Articles have appeared in various publications sponsored by the Navy— the Naval Institute Proceedings and The Naval Reserve Bulletin—in which Merchant Marine officers have been taken to task severely for this apparent dereliction, and especially for their failure to take advantage of the so-called “New Navigation” of the Navy.
Most of the strictures are of little moment and may be ignored. The tenor of the articles shows plainly that the deductions were made with but a superficial knowledge and a cursory examination of the subject discussed. No consideration was paid to the fact that the Navy and Merchant Marine, while kindred services, are so dissimilar as to be almost totally unlike. In aim and in purpose, in their very reasons for being and in the conditions which prevail on board the ships, they are as far apart as the poles.
That Merchant Marine officers are old- fashioned and out of date is belied by the fact that all the latest navigational improvements such as the gyrocompass, the direction finder, and the sonic-sounding machine can be found in daily use in the better type of seagoing Merchant Marine vessels.
The most caustic criticism, however, is that Merchant Marine navigators, because they make use of the time sight and do not look with favor on the altitude- intercept formulas, are lacking in their ability to avail themselves of the advantages of the so-called “New Methods” of celo-navigation. And yet, a careful analysis of the whole situation shows plainly that the methods they do use are as fully up to date as those advocated by naval textbooks, even if not of a much later origin. Therefore, the question is asked: What is modern navigation?
To answer this query intelligently, and to prove the statement made in the foregoing paragraph, it will be necessary to refer to the improvements made in the art of finding a ship’s position at sea since the days of the early navigator. It is also necessary to point out that modern navigation is not made up of any one principle or formula, but is a combination of several different principles and formulas; and there are a number of these combinations. And the combination which allows a navigator to accurately determine the true position of his ship with the least fuss and bother is, it is logical to believe, the best.
Prior to the invention of the chronometer, navigators found their way about mainly by dead reckoning. They were able to determine their true latitudes by the use of meridian altitudes, but their attempts to check their longitude by the observation of lunar distances and by such bizarre methods as the occultations of the moons of Jupiter were liable to great error. Even when chronometers came into general use navigators were handicapped by the fact that the true latitude, being an important factor, had to be known. It was a custom in those days when finding a longitude by the sun to take sights in the morning and then wait until a latitude had been found at noon before working out the longitude. If no meridian altitude was obtained, then the morning sights were discarded as useless.
The discovery of the Sumner line changed all this and freed navigators from the necessity of finding a noon latitude to determine their longitude. And the Sumner line, or the line of position as it is now called, is the basis of all modern methods of celo-navigation.
When Captain Sumner accidently stumbled onto the principle which bears his name, he evidently was unaware of all its possibilities. It may have occurred to him that his line was one at right angles to the bearing of the observed object, but as there were no ready-made azimuth tables in his day it was much easier to find the line by the use of two or more latitudes than it was to compute an altitude-azimuth.
The fate of all new discoveries and inventions is the same. Men with brilliant minds—but with little or no inventive genius—seize on them, turn and twist them about, deck them out in a new dress, and proudly exhibit the result as the offspring of their own brains. And Captain Sumner’s discovery was no exception to this rule. It is indeed true that navigators have been greatly benefited by this mental kidnapping; but despite the efforts to belittle the fame of Sumner by referring to his line as a line of position, the principle he discovered still remains a monument to the memory of the alert-minded seaman who gave it to the world.
The discovery of the Sumner line caused considerable stir in the maritime world. Volumes were written, and many were the suggestions offered for its improvement. The best suggestion was that of a Mr. A. C. Johnson. Johnson’s method, brought out about the time of our Civil War, 1864, to be exact, was the first to make practical use of the fact that the Sumner line was one at right angles to the bearing of the observed object, and he also was the first to make use of longitude factors.
Johnson’s method was immediately taken up by navigators the world over, but for some reason never found favor in the U. S. Navy. It is true that a half hearted attempt was made to use longitude factors by the insertion of table 38 in Bowditch; but no illustration of the principle involved was ever given except a short explanation in the index. Later, however, table 47 was also inserted.
While Johnson’s idea of reducing two or more position lines to a common point is still by far the best ever brought out— much easier and more certain than that advocated by the naval textbooks—his method had one weakness: the necessity of consulting a table of azimuths to obtain the bearing of the observed body. Later, this weakness was eliminated by a method suggested by Blackburne; and Blackburne’s tables, amended and improved by Lecky, are now in use by all navigators.
In 1874, ten years after Johnson and twenty years before Lecky, Admiral Marcq Saint-Hilaire brought out his now famous altitude-intercept formulas. There is no doubt but what Saint-Hilaire was influenced by the findings of Sumner and Johnson, in fact, his method is utterly impractical unless these principles are used. His formulas were examined and studied by the best mathematical minds of that day, but they were unanimously considered as being no improvement over existing methods.
Some twenty-odd years ago, the officials of the U. S. Navy, being dissatisfied with the ancient methods then in vogue in the service, adopted the Saint-Hilaire formulas as the standard method of navigation. To those who were unfamiliar with the most recent improvements in navigation, these formulas were something of a revelation; and they were immediately dubbed “New Navigation.” And yet, if one can judge from the articles which appeared in the various nautical publications of that day, this adoption was not made without considerable controversy, and feeling must have run high. For the time sight, favored by the opposition, was forever banned from use in all naval vessels.
As time rolled on, however, it became quite evident to the onlooker that the Saint-Hilaire formulas, with their long and complicated computations and the necessity of entering four different tables to find the seven, nine, and eleven functional quantities, were not altogether satisfactory. H.O. Publications 200, 203-4, 208, 209, and 211 have been issued in quick succession. And yet, a careful survey of the situation shows very plainly that the navigational ideas of the Navy are not one whit further advanced than those Johnson brought out over 70 years ago.
To an expert navigator, one who is familiar with all methods of celo-navigation, all methods of finding a line of position have their faults and shortcomings. None are infallible. It is also a well- known fact that a “fix” cannot be obtained from one lone sight. But a point on a line of position, if carefully studied, can impart valuable information; and there are many times at sea when a navigator must place some reliance on information thus given. During a long spell of heavy weather, which often occurs in high latitudes during the winter season, days may pass when it is possible to catch only occasional glimpses of the sun or stars. While one can never place absolute reliance on one observation, it is better than nothing. In an exigency of this kind it is incumbent on a navigator that he make use of a method which by long experience he knows to be the most reliable. Fanciful theories and untried methods should be barred. Ships —Merchant Marine ships—must proceed at all times. In these days of strenuous competition, shippers of freight and the traveling public demand the vessels they patronize must sail and arrive on schedule time, not only on a certain day, but at a certain hour, almost to the minute. A delay which would result in the loss of several hours of daylight might mean the difference between “red” and “.black” ink in the accounting department.
One great fault of the time sight, being mathematical—the approach of the cosine half-sun toward infinity as the observed body nears the meridian—is glaringly conspicuous to the mathematician; but this fault is more than offset by its virtues. The computation is extremely simple. It gives a point on the line of position with but very little fuss or bother in comparison with other methods. The difference between this point and the true position, being affected only by the error of the assumed latitude, is generally less than that given by any other known method. Furthermore, the correction of this difference, if the right method is used, is a very simple matter.
There are those who claim that the time sight should not be used except when the observed body is on or near the prime vertical. This is an error. The time sight may be used whenever it is practical to use any other known method. In one of the articles referred to in the beginning, one writer by the use of a carefully drawn diagram (p. 76, January, 1935, issue of the Naval Institute Proceedings) attempts to show what a terrible predicament a navigator would be in if he made use of the time sight. And yet, a position found by the use of a Saint-Hilaire formula would, if the same data were employed, be less than two miles away. Had the assumed longitude been to the eastward, the point given on the positional line would have been even farther away from the true position.
Theoretically, all altitude-intercept formulas are ideal, but they have many failings when used under the conditions which prevail at sea. These failings, being mechanical, are hard to find and difficult to explain. And this brings to mind the pithy saying of Huxley; “It’s a tragedy in science when a perfectly good theory fails in practice.”
The most conspicuous fault, yet by no means the most serious, that of the long and involved computation, has already been mentioned; and when this computation is completed one has no real position, only an intercept. To apply this intercept and to correct the error caused by the error of the assumed position calls for further computation which makes the whole problem a very long drawn-out and a very tedious proposition. In order to avoid this last calculation, the graphic method must be used, an expedient which in itself has many failings. Furthermore, in order to lay off the intercept—and this failing is common to all altitude-intercept formulas —one must compute, or take from a table of azimuths, the bearing of the observed object. This last operation is quite superfluous if modern methods are used.
As before pointed out, there are times when it is impossible to get but one sight; and a navigator must be able to make use of what information this one sight will give. In an extremity of this kind—and the safety of the ship may at times depend on the reliability of this information—the result given by an altitude-intercept formula is apt to be very misleading. This comes from the fact that the location of the computed point on the line of position is affected by the errors of both the assumed longitude and the assumed latitude. It is true that at times these errors will counteract each other, but at times the difference between the true and the computed positions will be widely separated. The trouble is that one never knows what effect these errors are having, and the information given is undependable.
In order to eliminate the long calculations necessary to complete the working of a problem by an altitude-intercept formula, naval navigators make use of the graphic system. It is indeed astonishing to note that the Navy, with its passion for exactitude and its meticulous regard for precise calculation, should countenance the use of what has been defined by one of the greatest authorities on navigation as a clumsy, awkward, and slipshod method.* It has many faults and shortcomings.
In the use of double or simultaneous altitudes when the angle of incidence of two or more lines of position is small, the meeting point will be indeterminate by several miles. The parallel ruler is a tricky instrument, especially in heavy weather when a navigator has difficulty in keeping his footing. The slightest slip, if the intercept is large and the difference between the true and the assumed positions is also large, will result in a large error. This difficulty has been recognized by naval navigators, and costly drafting machines have been installed in the chartrooms of all naval vessels to eliminate this danger. But imagine the reaction—and the language—of a hard-boiled marine superintendent of a line of Merchant Marine ships, worried and harassed over mounting expense of operation, when confronted by a requisition for one of these expensive trinkets by an officer who wished to navigate navy style.
Furthermore, the use of the graphic method does not allow a navigator to keep a complete record of all his work in finding a position. Unless the chart on which he plots his work is kept, a situation which seldom occurs, all record of the most important part of his labor is lost. It is possible for a navigator to make a mistake in laying off a line of position, and although he may have completed his computations with the utmost exactitude, this mistake can never be discovered.
The above is not meant to decry the plotting of a position line under certain conditions. If the observed object is abeam, a contingency which seldom occurs, and the ship is on soundings, it is possible to obtain a “fix,” or to ascertain what landfall will be made. Also, a “fix” can be had by one sight if a well-known landmark having the same, or nearly the same bearing, is in sight. But the plotting of a line of position when a vessel is in mid-ocean is decidedly amateurish, an artifice of one who is not quite sure of himself.
A summary of the above failings and shortcomings shows very plainly how inadequate any altitude-intercept formula is to meet the requirements of the practical navigator. None of them can compare in simplicity or exactness to the time sight. One has only to compare the problem shown on page 195 of the 1935 edition of the American Practical Navigator with those shown on pages 196 and 199. And one may ignore the computation of the altitude azimuth of the former, for with the most modern usage it is not necessary to know the bearing.
But after all is said and done, the safe and efficient navigation of a ship is not all figures. It is mostly common sense and good judgment; and these qualities are only acquired by long experience. Theory cannot be disparaged, but a knowledge of theory alone will never make a skillful and reliable navigator. If one could always have perfect weather, if the horizon were always visible and if the sun, moon, stars, and planets were always available, navigation would indeed be a simple matter, hardly beyond the mentality of a high- school student. But under the conditions which are met at sea, the most successful navigator is one who keeps a careful account of his dead reckoning, correcting this reckoning by celestial observations. It is indeed a true saying; “A smooth sea ne’er made a skillful mariner,” to which might be added that fine weather never made an expert navigator. Therefore, it is not so much the reliance on abstruse mathematical formulas which allows a seaman to bring his ship safely to port, as it is the right use of simple problems, rightfully applied.
A general in chief is not relieved, of responsibility by an order from a minister or a prince far from the field of operations and knowing badly or not knowing at all the last state of affairs: (1) Every general-in-chief who undertakes to execute a plan which he thinks bad or injurious is criminal; he ought to make representations, to insist upon a change, finally to resign rather than be the instrument of the ruin of his own people; (2) Every general-in-chief who, in consequence of orders from a superior, delivers battle with a certainty of losing it, is equally criminal; (3) A general-in-chief is the first officer of the military hierarchy. The minister, the prince give directions to which he must conform in his soul and conscience; but these directions are never military orders and do not exact a blind obedience; (4) Even a military order is to be blindly obeyed only when it is given by a superior who, being on the spot at the moment of giving it, knows the state of affairs .... Napoleon in his Memoirs, treating of the duties of generals.