 
CROSS-BEARINGS.Perhaps there is nothing more useful in simple coast-sailing and entering harbors than to know how to find one's exact position upon the chart, at a moment's notice, by means of taking what is called cross-bearings. Nothing is necessary for this purpose, but a pair of parallel-rulers, a compass, and a sight of any two well-defined objects in view, that may be known upon the chart by their general relative positions, such as lighthouses, lightships, buoys, churches, headlands, &c. The parallel-rulers are two rulers attached by The writer knows of nothing so important and useful as this simple method of knowing just where one is at any moment, and thus be enabled to know just how to steer to avoid all dangers. These sights, or cross-bearings, can be taken every ten minutes with ease in fine weather, and the position of the yacht exactly defined. Example I. (see diagram, Fig. 1).—Bring the compass in its box on deck (it should be of large size, so as to guide the eye; and small pocket-compasses are useless for this purpose), and, standing behind it, line with the eye with great care the bearing of the north lighthouse by the compass, this we will suppose to be N.W. by N.; mark this upon It will be shown too, by experiment, that considerable variation of the bearings, when the angle is large, may be made, without changing very much the position of the yacht, proving how valuable this process is for practical use, as a considerable error in the bearings will still enable one to know almost exactly the position of the yacht; whilst a good observation will give it exact. Determining position (2) Example II. (see diagram Fig. 2).—Placing the compass in front of the observer, it is found that the lighthouse bears W. by compass, and that the lightship bears S. W. by S. With these two bearings we consult the chart, and lay off the two lines by means of the parallel-rulers; and, if the chart gives the distance in miles of the lightship from the lighthouse, then, by means of a common rule of equal parts, we shall be able to measure the distance of the yacht from the lighthouse or from the lightship. At the foot of most charts, however, will be found a scale of miles, and, having once ascertained the exact position of the yacht by means of cross-bearings, it will be very easy, with a pair of dividers, to find its distance in miles from any desired object within view, or designed upon the chart, and, by the use of the parallel-rulers, the course, by compass, that should be sailed to reach any desired point. It is often useful to know how many geographical or nautical miles, which measure at the equator
Note.—Enter the table in the column of height in feet, which represents the height of the observer above the sea; and opposite to it, in the column of miles, will be the result. Column [A]: Height in Feet.
Example I.—Sailing along in the yacht "Firefly," from the top of the house on which I was standing, which brought my eyes to about 12 feet above the level of the sea, I observed seaward the head of a gaff-topsail that evidently belonged to a In the table,
Example II.—Sailing towards the land, I mounted the shrouds of my yacht till my eye was about 16 feet above the level of the ocean, where I sighted the top of a known lighthouse that I was looking for, which the chart informed me was 145 feet above the level of the sea. Required the distance of the lighthouse. In the table,
Upon seeing the flash of a gun I counted 30 seconds by a watch before I heard the report. How far was the gun from me, supposing that sound moves at the rate of 1,142 feet per second? The velocity of light is so great, that the seeing of any act done, even at the distance of a number of miles, is instantaneous. But by observation it is found that sound moves at the rate of 1,142 feet To find the difference between the true and apparent direction of the wind. Wind direction Suppose that a yacht moves in the direction C B from C to B, while the wind moves in its true direction from A to B, the effect on the boat will be the same as if she be at rest, and the wind blow in the direction A C with a velocity represented by A C, the velocity of the yacht being represented by B C. In this case, the angle B A C will represent the difference between the true and apparent direction of the wind, the apparent being more ahead than the true; and, the faster the vessel goes, the more ahead the wind will appear to be. We must, however, except the case where the wind is directly aft, in which case the direction is not altered. It is owing to the difference between the true and apparent directions of the wind that it appears to shift its direction by tacking ship; and if the difference of the directions be observed when on Thus, if the velocity of a yacht, represented by B C, be 7 miles per hour, that of the wind, represented by A B, 27 miles per hour, and the angle with the yacht's course, with the apparent direction of the wind B C A, equal to 7-1/2 points, the difference between the true and apparent directions of the wind will be obtained by drawing the line B C, equal to 7-1/2 points; then with an extent equal to 27 miles, taken from the scale, and with one foot in B, describe an arc, to cut the line A C in A; join A B; then the angle B A C, being measured, will be the required difference between the true and apparent directions of the wind. Sailing in my yacht, I saw a lighthouse bearing E. by N., and, after sailing 14 miles N. by W., it bore S. E. Required the distance of the yacht from the lighthouse at both stations. Measuring distances Solution.—Describe the compass E. S. W., and let its centre X represent the place of the yacht at the first station; draw the N. by W. line, X Y, equal to 14 miles, and Y will represent the second station. Draw the line E. by N., X Z, of an indefinite length, and the line Y Z parallel to the S. E. and N. W. line of the compass: the point of intersection Z will represent the place of the lighthouse, and the distance Y Z, being measured by the same scale of equal parts with which the 14 miles of course is laid off, will be found to be 16-3/4 miles, and X Z 9-1/4 miles. USE OF THE CHARTS.Charts can be purchased, at a very reasonable rate, of all the important harbors and the whole coast-line of the United States. They come nicely backed with cloth, so as to stand considerable hard sea-usage. They should be kept, when not in use, rolled up in a large tin box made for the purpose, or a long, narrow wooden trunk, called a chart-box. In using charts, great care should be taken to see whether or not the courses laid down to be sailed are magnetic ones; that is, with the variation of the Always carefully read all the notes upon the margins of a chart: one will often run across an item of the greatest interest or importance. Nearly all charts of harbors and the coast-line will be found with two scales of miles upon them; one being marked statute miles, and the other nautical miles. Now, the difference is this, the scale that is marked statute miles means a mile of 320 rods of 16-1/2 feet each, or 1,760 yards of 3 feet each, or 5,280 feet; whilst a nautical mile means the sixtieth part of a degree of the earth's surface measured at the equator, which is about 6,086.4 feet in length. SOUNDINGSAre very regular upon the American coast; and if the time of tide be known, and the note concerning soundings, on the margin of the chart, consulted, one can often, when caught in a fog, tell quite correctly the position of the yacht, its general place upon the chart being known. The Lead-Line.—For the purpose of getting soundings, the lead-line must be used, of which there are two kinds,—the dipsey lead, i.e., the deep-sea lead, and the hand lead. The deep-sea lead consists of a lead sinker, usually about twenty-five pounds in weight, the lower part of which is hollowed Heaving the Hand Lead.—The hand lead is used in a different manner, and is the most perfect instrument yet devised to warn the yachtsman or sailor of unknown dangers and the rapid shoaling of the water, or approach to some unknown or unexpected shoal. Custom has, from time immemorial, marked the lead-line in a peculiar and, the writer does not hesitate to say, ridiculous manner, which can be understood by the initiated only. But that it may be done according to "Gunter," and in "ship-shape and Bristol fashion," the following explanation is given:— Heaving the lead is done usually by a person who is placed in the main-chains for that purpose, on the weather-side, or, in smaller craft, on deck, forward, just clear of the shrouds. It is thrown whilst the yacht is under way, and being kept on her course, and the results announced in a singing voice by the one casting; and, when the water becomes too shoal, the yacht is put about, and stands off from the danger which she was approaching. The one casting the lead takes hold of the line at about a fathom from it, and swings it to and fro till enough velocity is gained to swing it over his head; when at the right angle it is released, and flies forward At1 fathom one knot. Those that are marked are called "marks," the others, "deeps;" and a lead-line as above consists of eleven "marks" and nine "deeps." If the mark of three fathoms is near the surface For all practical purposes a lead-line twenty fathoms in length, but marked only to ten fathoms, will be the most useful for yachts and small sail-boats. This line should be marked as follows:— At1 fathom one knot. A small piece of white rag may also be inserted at the half-fathoms between two and three. EIGHT BELLS, AND WATCH AND WATCH.Time at sea is divided differently than on shore; and the day commences at twelve o'clock, noon. The time of twelve o'clock is denoted by striking the vessel's bell eight times in a peculiar manner, thus: by sets of twos, one, two, rapidly following each other, then a pause of three or four seconds, and then the next set of twos, thus: one, two—one, two—one, two—one, two; whilst seven bells would be struck thus: one, two—one, two—one, two—one; and three bells: one, two—one; four bells: one, two—one, two. This system of eight strokes of the bell does for the whole twenty-four hours, each stroke denoting one half-hour: hence eight bells cover a space of four hours, which is termed a watch, and, if each watch was four hours long, of course there would be six such watches in the twenty four hours; and the crew, divided as they always are into starboard and port watches, would, during the whole voyage, have just the same hours on deck. That is to say, the starboard watch would come on deck at twelve o'clock noon every day of the voyage, and stay till four P.M. This would not be fair to the other watch; and to avoid this repetition, and to divide the time differently
In cases of emergency, usually to take in sail, whether by night or day, "All hands on deck to take in sail, ahoy!" "Heave up my hearties!" is bellowed into the forecastle, and comes to the ears of the unwilling sleepers of the watch below. BOXING THE COMPASSIs the term used for repeating the thirty-two points of the compass-card by memory from the right hand to the left, (and then back again,) commencing at north, and proceeding to north by east, north, north-east, &c. It is necessary that the amateur and young salt should acquire this, if he desires to ever be able to make use of the most simple problems in boat-sailing, the use of the charts, the finding of the position of the yacht by cross-bearings, &c. In fact, it is indispensable; and the task should be commenced at once. It should not be gotten by rote, without rhyme or reason; but, in repeating the names of the points, the compass-card, or a printed imitation of it, should always be kept before the eye [see frontispiece]. After acquiring the regular thirty-two points, the subdivision of quarter and half points are to be gone into. The smallest division used in navigation is a quarter of a point; thus your course may be N. by E. 1/4 E., or N. by E. 1/2 E., or N. by E. 3/4 E.; but no smaller subdivision is ever made between two courses than one-quarter of a point. This is as near
If any one desires to be very salt, he will pronounce these points as follows:—
And, in fact, the above is the way that they are pronounced by all sailors. It should be remembered that the compass does not move; that is to say, the yacht moves, which seemingly makes the card in the compass-box revolve. It is absolutely an optical illusion to "land-lubbers" and except by the jar of the yacht, or by pitching about in a heavy sea, the compass-card does not revolve, but is stationary, and it is the change of the course of the yacht which seems to give it motion. TO PLACE A COMPASS TO STEER BY.The periphery of the circular casing in which the card revolves should be marked plainly with a perpendicular black line; and this black line should, by moving the compass-box, be brought to bear in a direct line with the keel of the yacht, and the box secured in that position. One has then only to move the helm to bring each and every point on the compass-card opposite to this black mark on the compass-box, and, having once brought the point needed to this position, keep it there by moving the helm when necessary; and this act of keeping it there is called "keeping the vessel on her course." For instance: if the wind allows, suppose by the chart it is desired to steer N.E., to reach a certain place. Go on deck, and, by moving the helm, bring the N.E. point of the compass-card opposite to the black perpendicular mark on the compass-casing, and keep on your way, after having trimmed your sails so as to hold the wind properly. The yacht will not keep on N.E. exactly, but will yaw to and fro, which will seem as if the compass-card was moving; and this will occur more or less according to the roughness of the water. And, if one looks too much to the compass, the yacht will be off the course before the compass shows it: it is therefore well, if possible, to get some bearing, VELOCITY OF WIND.Generally speaking, a wind that blows sixteen miles an hour is called a fresh breeze. One that blows eighteen miles an hour calls for a single reef; and twenty miles, a close reef. Twenty-four miles an hour is a gale; whilst thirty miles an hour is a fresh gale. THE LOG, REEL, AND HALF-MINUTE GLASS.This method of ascertaining how fast the yacht is moving through the water, and hence to calculate her position, has been almost done away with by the use of what is termed the "patent log," which is now almost universally used, and which consists of To ascertain the velocity at which the yacht is sailing is called heaving the log, and is performed as follows: one person holds the reel, and another the half-minute glass, whilst a third throws the log over the stern on the lee-side; and, when he observes that the stray line has run off (which is about ten fathoms), and the first mark (which is generally a red rag) has passed the stern, he sings out, Turn: the glass-holder answers, Turn, and, watching the glass, the moment it has run out, sings out, Stop. The reel being immediately stopped, the last mark run off shows the number of knots that The log-line is marked as follows: allow ten fathoms for stray line, and then insert a red rag, and at every 47.6 feet mark the line as follows: at one, one leather; at two, two knots; at three, three knots; and also have a small mark at each half-knot, and so on to ten and twelve knots. The principle of the log-line is, that a knot is the same part of a sea-mile that half a minute is of an hour: therefore the length of a knot should be one hundred and twentieth the length of a sea-mile, or fifty-one feet; but, as it is more convenient to have the knot divided into eight parts of six feet each, the proportional reduction is necessary in the half-minute glass. BUOYS.In entering harbors, the red buoys are to be left upon the starboard hand, and the black buoys upon the port hand. MAN OVERBOARD.Throw overboard at once any light object that will float, such as a stool, oar, boat-hook, or life-preserver, for him to grasp; then bring the yacht at once to the wind and heave her to, and pick up the man with the tender, or by going about and standing for him. Don't look out astern for the man where he disappeared, but out on the beam, which will be his position when the yacht is brought to the wind. |
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