THE LAW OF STORMS,
CONSIDERED WITH SPECIAL REFERENCE TO THE NORTH ATLANTIC.
BY EVERETT HAYDEN.
(Abstract of a paper read before the National Geographic Society, Nov. 15, 1889.)
In preparing an abstract of this paper it is of course difficult to adhere very closely to the original, inasmuch as that was illustrated by forty-five lantern slides, while it is only practicable to present a few plates with this abstract. I may therefore be permitted to give only a general outline of the subject, with perhaps a more detailed discussion of one or two of the most notable recent hurricanes off our Atlantic coast.
The term "Law of Storms" is applied to the code of rules that should govern the action of the master of a vessel when he has reason to suspect the approach of a dangerous storm. It will be seen that this definition, like the code itself, is somewhat vague. So many considerations enter as factors in the question that it is wholly impossible to lay down any rules that shall be applicable alike to a high-powered, well-manned steamship, and to a heavily-laden, poorly-equipped and short-handed sailing vessel. Disregarding such differences of conditions (which are, of course, of vital importance in each individual case, but which cannot be discussed in a brief general essay), the two grand divisions of the subject may be compared to grand strategy and field tactics. By this I mean that a broad, comprehensive view of the whole subject of ocean storms—their regions, seasons, size, severity, and tracks—is one very important part of the navigator's duty in planning a long campaign, or voyage; and, secondly, the handling of his vessel when actually in the fight—the coolness, clear-headedness, and trained experience that utilizes every resource of the best seamanship and navigation in a fearful struggle with the fury of a hurricane—all of these are also an essential part of the education of the ideal sea-captain.
Thanks to the progress of meteorologic research it is comparatively easy nowadays for anyone to get a very good general idea of the great hurricane regions of the globe, and the seasons when these dreaded tropic cyclones prevail in each of these regions. The evidence on this subject is cumulative and practically conclusive, so that it is universally known and recognized that the hurricane months are the summer months in each hemisphere; hurricanes originate in the tropics, move westward, then poleward into the temperate zones, and finally eastward in higher latitudes, receding gradually from the equator; moreover, the essential difference between hurricanes north and south of the line is as follows: In the Northern Hemisphere the rotation of the cyclonic whirl is against the hands of a watch, and in the Southern, with. The noted hurricane regions are the West Indies, coast of China and Japan, Bay of Bengal (especially in May and October, at the time of the change of the monsoons), and the South Indian Ocean (about Mauritius). Less noted regions are the South Pacific (East of Australia), the North Pacific (west of the Mexican coast), and the Arabian Sea. In planning a distant voyage a navigator should therefore consider the hurricane regions through which he must pass, just as he considers the prevailing winds—the trades, monsoons, and ocean currents.
The handling of a ship in a hurricane is a very different sort of a thing from this general survey of the entire field, and, without the eminently practical qualities that we all associate with a good officer of the navy or mercantile marine, no mere theoretic knowledge can avail much. And yet this is one of those cases where practice and theory should go hand in hand,—not theory as something vague and unreal, but theory as based upon a firm foundation of observed facts. If a vessel encounter a hurricane, certain conclusions can be drawn from observations of the shifts of wind, the fluctuations of the barometer, the appearance of the clouds, and the direction of the ocean swell; the master of that vessel will undoubtedly draw such conclusions, and store them away in his mind as part of his fund of experience upon which to base action at some future time. But if he can consider his own observations, while fresh in mind, in connection with the observations made on board many other vessels that encountered the same storm, and modify or verify his conclusions by such comparison, there cannot be a doubt but that the lesson will be of far greater value. Sailors lead a rough life, and their training is often acquired by experience alone. Moreover, there are certain things that tend to discourage effort on the part of junior officers, even on board naval vessels: they realize that their duty is not to originate orders but to execute them, and sooner or later they get out of the habit of reflecting upon the action taken to avoid a storm or manoeuver in one, not knowing at the time what considerations lead to the action that was taken, and not always having anything brought forcibly to their attention to indicate with certainty whether the action was well-considered or ill-advised. Upon finally attaining command themselves they are not, therefore, as well posted as they might otherwise have been. I mention these things to explain the undoubted fact that comparatively few masters of vessels are well posted in certain very important additions to the old law of storms, as it was discovered by Redfield and enforced by Reid, Piddington, Thom, and other early writers. In fact, of all the navigators of various nationalities who have charge to-day of the commerce of the world, probably four-fifths are wholly ignorant of the progress that has been made in this direction in the past fifty years. That such is the case is not, in my opinion, wholly their fault: it is owing to the fact that far too little attention has been paid to clear, forcible, and convincing explanation; it is the fault of the teachers, no less than the scholars,—of meteorologists who talk over the heads of their audiences, instead of stating facts and conclusions in a way to command attention and respect from the practical men who furnish the data, and who deserve some tangible results in return for their long years of voluntary observation.
| A ship in the heart of a cyclone. From Reid's "Law of Storms." |
It is difficult to put this matter very clearly to those who are not familiar with the conditions that govern the management of a vessel at sea, and I shall only attempt to do so in a very general way. It should be understood, first of all, that a hurricane is an enormous whirlwind, so large, in fact, that its circular nature was generally recognized only about fifty years ago. At the immediate center of the whirl there is a calm space, from five or ten to thirty or forty miles in diameter, generally with blue sky and bright sunlight. Within a short distance of this central calm the wind blows with frightful violence, and here a vessel is driven along in absolute helplessness, enveloped in midnight darkness, buried in a flying mass of foam and spray, with every sound annihilated by the roar and shrieks of the elements. The core of the hurricane, as this region has been called, is small, relative to the entire area, and it thus happens that a few miles may make all the difference between shipwreck and safety. The question is, then, to avoid getting into the core, or heart, of the hurricane. It is evident enough that if the wind blow in a strictly circular direction around the center, the bearing or direction of the center must be at exactly right angles (eight points) to the right (or left) of the direction of the wind. In other words, in the Northern Hemisphere (where the direction of rotation is against the hands of a watch) the center bears eight points to the right of the wind (that is, to the right of the direction from which the wind blows); in the case of a hurricane off our coast, for instance, if the wind be NE. at Hatteras the center would bear (according to the 8-point rule) SE. Considering, further, that the entire whirl has a progressive motion along a path, or track, if an observer at Hatteras find that the NE. wind freshens rapidly, without any shift or change of direction, it is equally evident that the center of the storm is approaching directly toward that point. In a similar situation at sea, a shipmaster would naturally see that his vessel was in a position of great danger: evidently the best thing to do would be to run before the wind, thus getting out of the way of the approaching hurricane. This simple case will explain pretty clearly, I think, how rules were at once formulated and adopted, as soon as Redfield had proved the approximately circular character of these storms.
Without going further into this subject, inasmuch as this 8-point rule is perhaps the most important of all the rules—indeed, all of them follow directly from it,—suppose that subsequent research, based upon careful observation and the accurate charting of hundreds of reports from vessels in similar storms in various oceans, proved conclusively that the wind in a hurricane does not blow in strictly circular whirls, but rather spirally inward, so that with a NE. wind off Hatteras the center bears probably S SE., or even South: evidently this is a matter of vital importance to the navigator, and all the old rules should be remodeled to suit the discovery. Such is, indeed, actually the fact, and in most cases nothing could be worse than to run directly before the wind; in any event it would be dangerous, and in the case of a slow-moving cyclone it might readily lead the vessel directly into the core of the hurricane. This is known to have been the case in many instances, and vessels have thus been drawn into the inner whirls of hurricanes and kept there for several days, making one or more complete revolutions around the center before they could extricate themselves. In fact, they might never have gotten out, if the storm itself had not moved off and left them.