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NOVEMBER 21, Igol. ' THE PRINCIPAL CAUSES OF STRANDING. Stress of weather excepted, strandings are always due to errors in position, caused by the use of a defective log, of defective astronomical methods, and of defective methods for finding position by soundings. _ The logs in use are the common log, and the patent log, both floating on the water and partaking of set and drift of currents, Floating logs give only the distance run on the water and not the distance over the ground. The position by floating log is always so much in error as the current sets during the run, involving errors in courses as well as in distances. The invariable basis of all directions is the true or as- tronomical meridian laid down in the chart. courses by the ship’s compass to the chart, four course corrections are required, namely, 1, deviation; 2, leeway; 3, current; 4, variation; of which only the last one is known and generally given in the chart; the other three depend on observations at the beginning of, and during the _ voyage. Deviation is generally’ ascertained by astro- nomical observation ; leeway equals the angle which the wake makes with the fore and aft line of the ship; the correc- tion for leeway and current combined equals the angle which the horizontal projection of the ground log-line makes with the fore and aft line of the ship. As only the floating log is used aboard ship the correction for current cannot be found, and therefore has to be neglected, causing an error in the course made good, equal to the amount of the neglected correction, equivalent to as large an error in variation or deviation. As ocean currents have a velocity up to two miles per hour, the error in the course made good, on account of neolecting the course correction for current, is sometimes considerable. With vessels making only ten miles per hour the error equals up to one point in course. The rate of current divided by the rate of the vessel’s speed, furnishes a quotient, which multiplied by the dis- tance run by floating log gives the radius of a circle, which may be called the circle of uncertainty, because the direc- tion of the current is not known, on the peripherv of which circle the vessel is found to be, instead of at its cen- ter representing her positon by floating log. The radius of this circle increases with the distance run, and decreases as the speed of vessels increases. As long as the circle of uncertainty does not touch the shore or any obstacle, the vessel is safe, but otherwise stranding may. be expected every moment. The radius of the circle, equal to the drift of current, determines the distance from the nearest’ ob- stacle, at which distance it is not safe to run any further without verifying position. For instance, the ship’s rate being ten times the rate of current, a safety margin of one- half point in course is required to pass any obstacle, and after a run of 1,000 miles by floating log, the radius of the circle of uncertainty equals roo miles, and if this circle nearly touches the land or. the light to be made, the ship has to verify position before running any further . After verification the distance yet to be traversed being 150 miles, and the same conditions prevailing as previously, the radius of the circle of uncertainty equals 15 miles, at. which dis- tance from the object verification of position is again re- quired. Which shows, that verification of position is neces- sary at certain intervals; and the nearer the land the often- er it has to take place, in order to avoid stranding. ‘The circle of uncertainty not being taken into account, as is generally the case, vessels get stranded by sheer neglect of verifying position in time, frequently causd by the lack of astronomical methods to reduce available observations. he use of the floating log makes it imperative to verity posi- tion as often as an opportunity offers, in order to bring the radius of the circle of uncertainty down to a minimum; and the want of astronomical. methods for reducing all available observations is therefore so much keener felt All astronomical methods used in practice are based up- on the one object theory depending on the change of posi- tion by compass and log during observation, which change is a very uncertain element, because of unknown currents; and consequently results by one object methods cannot al- ways be depended upon. Besides, nine-tenths of all the methods in use are mathematically not correct, and as a consequence the results by them are sometimes largely in error (see the MARINE REcorp of November 8 and 29, 1900, and of January 10 and February 28, 1901.) In mid-ocean errors in position cut no figure, but in the vicinity of land every error counts and contributes to stranding. An error in the last point of departure by astronomical observation, causes an error in all subsequent positions by. compass and Jog, and therefore may cause stranding, especially in thick weather. Another defect of the methods in use is, that some of them are not applicable to all heavenly bodies, pre- venting vessels to avail themselves of all the opportunities offering for observation; and finally, results by one object methods are delayed, sometimes for hours, because of hay- ing to wait for the object to come into the desired position -for observation. All these defects, drawbacks and delays contribute to stranding; they are avoided by using my two object method, published in the Martngé Recorp of April 19, 1gco, furnishing instantaneous and exact results. In thick weather, and in the vicinity of land, the bottom of the sea is the only available guide. The configuration of the ground as indicated by soundings generally furnishes the data for finding the place the ship is in. Navigation by soundings is the most important branch of navigation, but has never been made the subject of scientific study, and therefore is entirely wrapped in mystery. What little light has been shed upon it emanates from Sir Thomson’s “L,ec- ture on Navigation” in which he says: To transfer THE MARINE RECORD. “Take a long slip of card, or of stiff paper and mark along one edee of it points at successive distances from one another, equal eccording to the scale of your chart, to the actual distance estimated as having been run by the ship in the intervals between successive soundings. If the ship has run a straight course, the edge of the card must be straight, but if there has been any change of directions in the course, the card must be cut with a corresponding deviation from one straight direction. Beside each of the points thus marked on the edge, write on the card the depth and char- * acter of bottom found by the lead. Then place the card on the chart, and slip it about till you find an agreement be- : tween the soundings marked on the chart and the series marked on your card.” ‘To which Capt. Vecky, in his book ° on navigation, rightly remarks, that tracing paper is pref- erable to cardboard. The advice of Sir Thomson, however, is rendered illus- . ory by the well known fact, tnat courses and distances made good, forming the basis of the soundings taken, are not obtainable by the exclusive use of the floating log; and that without a correct basis comparison of soundings with the chart, if not impossible, is deceptive in the highest de- gree. Even when courses and distances made good are found by the ground log, the method suggested can be depended upon only under certain conditions and with certain limitations, as will be seen from the following: On account of the pitching and rolling of a vessel an error in course and distance is unavoidable. Supposing the error in course to be 4% point, and in the distance 1-20 the distance run; 14 point in course is equivalent to a side- way error of 1-20 the distance run; consequently, as errors may be positive or negative, they have to be assumed both ways, and the uncertainty in position is represented by a square the side of which equals 1-10 the distance run; the center of the square being the position by compass ‘and ground log. Within this square the sounding taken per- tains to a curve or horizontal, its part within the square forming a certain angle with the ship’s course; and it is obvious, that if this angle is nearly zero, only the course is corrected or verified; and if this angle is nearly 90 degrees, only the distance is corrected by the sounding. Conse- quently, if angles differ much from o and oo degrees, neither the course nor distance can be verified by the sounding. What applies to a single sounding applies to all soundings taken. From which follows, that to correct courses, the horizontals of soundings have to: be nearly parallel with the ship’s course; and to correct distances they have to be nearly at right angles to the ship’s course, Furthermore, to make sure courses, they have to be shaped in agreement with the di- rection of horizontals or coincide with them. This prin- ciple is partly expressed by Capt. Lecky, in the following passage: “In navigating an inlet and unmarked channel, where the water shoals pretty gradually on each side, the safest plan is not to attempt to steer a mid-channel course, but to zig-zag it, keeping a lead going in both chains. By this plan you can tell which side you ?re on, and how to put the helm to avoid danger.” At sea generally but on one side the shore has to be watched by the lead to insure safety by not: overstepping a certain curve, called the safety curve, being a curve of equal depth along a certain part of the. coast, or around shoals and reefs, at a safe distance from the danger nearest to the curve . Outside of the safety curve the ship is free to shape her courses; and in order to run the least risk of crossing the safety curve, a curve of greater depth than the depth of the safety curve, and nearly parallel to it, has to be selected as guide by the lead. Thus courses are made safe and sure. and distances only depend on the log for a certain space of time. The verifica- tion of distances by the lead, presents some easy problems which cannot be enumerated and explained here for want of space. ‘ Because safety curves and guiding curves are not used in practice, vessels always get stranded weather. With faulty logs, faulty and limited astronomical meth- ods, an incorrect basis and theory for soundings, and some- times incorrect charts, vessels cannot be expected to avoid stranding. JoHN Mauricg, Civil Engineer and Nautical Expert. Chicago, November, 19oT. ———— i oe eo VESSELS CLASSED. The vessels classed and rated this week by the American Bureau of Shipping in the Record of American and For- eign Shipping, New York, are:as follows: Screw Interna- tional, screw Simon J Murphy; schooner Samar, schooner Orlando V. Weotten, schooner Ruth, schooner Savannah, schooner Henry 8. Fiske, schooner Francis C. Tunnell, 3-masted schooner Fannie I,. Child 3-masted schooner Olga, 3-masted schooner Helen G. Mosely, bark Antioch, bark H. G. Johnson; ship William P. Frey. %-brig C. C. Sweeney, barge Sancon, barge ‘Trevorton, British schooner Ida, British 3-masted schooner John S, Parker, British 3-masted schooner Palma and Portugese '%-brig Vera Cruz 5th a Tue New York Chamber of Commerce has decided in favor of the creation of a department of commerce and industry, the head of which shall sit in the president’s cabinet. Such a department would consolidate - various bureaus now under the direction of the secretaries of the treasury, state and agriculture, and would insure much better work in furnishing the interests of our trade abroad. in fog and thick: ‘SHIPPING AND MARINE JUDICIAL DECISIONS. (COLLABORATED SPECIALLY FOR tHE MARINE RECORD.) - Damages-—Personal Injury—Reduction of Amount on Appeal—An award of $12,000 damages, made. by a court of admiralty for a personal injury received in’a collision, reduced to $60,0co0 on new evidence taken in the appellate court, showing that the improvement in the condition of libelant since the trial was such as to indicate that the injury was not so serious or permanent as it appeared at the time of the trial. ‘The Homer, 1o9 Fed. Rep. (U. S.) 572. Carriers—Steamship—Overcrowding Passengers—Dam- - ages.—Where a steamship company having accommodation for and authorized to carry only 375 steerage passengers sells tickets to ‘and receives 475 such passengers, and by reason of overcrowding the passengers are delayed and in- jured, the company is responsible for such damage, since such crowding beyond the point at which the passengers could be safely carried is a breach of the contract to safely carry them. ‘The Valencia, 110 Fed. Rep. (U. S.) 2ar. Admiralty—Intervention.—Marine insurers, who, by pay- ment of a loss resulting from the injury of a vessel in col- lision, have become entitled by subrogation to a‘portion of the fund recovered by the owners from the vessel in fault, may intervene and set up their claim thereto after a decree has been rendered in favor of such powers on a mandate from the appellate court, the issues raised by such inter- vention relating solely to the distribution of the fund re- covered. Mason et al. vs. Marine Ins. Co. et al., 110 Fed. Rep. (U. 8.) . 452. Collison—Failure to Display Light—Tug and Tow.— Where a canal boat being towed alongside a tug at night ina harbor failed to display a white light on her outboard bow, as required by inspector’s rule 11, both the tug and the ca- ~ nal boat are chargeable with the fault; and the tug is’ not exonerated from liability for a collision resulting by the’ fact that her master ordered the master of the canal boat to put out the light, but it was his further duty to see: that his order was enforced. The Nettie L. Tice, t10 Fed.- Rep. (U. S:) 461. Shipping—Loss of Cargo—Unseaworthiness of Lighter. —A lighter, so constructed that the presence of any water in the hold rendered it unstable’ when ‘loaded; which over- turned shortly after being loaded, when the weather was clear, the wind light, and the water smooth except from.a slight swell caused by a passing steamér, by reason ‘of water entering her hold through seams which were in-. sufficiently calked, must be held. unseaworthy when loaded. | Nord-Deutscher Lloyd vs. President, etc., in Insurance Co. ° of North America, 110 Fed. Rep. (U. S.) 420. Marine Insurance—Effect of Abandonment to Insurer— Right to Damages Recoverd for Collision—The effect of the abandonment to the insurers of a vessel sunk in col- lision is to vest in the insurers not only the title to the property abandoned, or its proceeds, but also the right to whatever may be afterwards recovered or received as a compensation for the loss; and damages recovered from the vessel in fault for the collision, for the loss of pros- pective earnings of the vessel sunk, belong to ‘the insurers, and not to the insured. Mason et al. vs. Marine Ins. Co. et al., 110 Fed. Rep. (U. S.) 452. . Judgment—Conclusiveness.—Lieblants ‘shipped petro- ~leum, covered by marine insurance, on’ board a bark which> became disabled at sea. Salvage and other experfses were incurred, to’ pay which the ship and cargo were subse- quently sold by the master. Held, in an action on the policy, that a judgment in an action on the master’s bot- tomry draft, pledging ship and freight, in which the sale of the ship was held invalid, was not admissible in evi- dence, nor binding in any way, it being between different parties, and on different evidence. De Farconnet et al. vs. Western Ins. Co., t10 Fed. Rep. (U. S.) 405. Seamen—Prepayment of: Seaméen—Constituional Law.— Section 24 of the act of Congress of December 21, 1868, en- © titled “An act to amend the laws relatiny to American sea- men, for the protection of such seamen, and to promote commerce” (30 Stat. 755), in prohibiting the repayment of: the wages of seamen, is a constituional enactment, applying to the prepayment on American soil or in American waters of the wages of seamen, who are Britsh subjects, shipping in American ports on British merchant vessels; there be- ine no treaty between the United States and Great Britain inconsistent with such application. ‘The Kestor, 110 Fed. Rep. (U. $.) 432. Anticipation of Danger—-Damages to Scows.—A tug hav- ing in tow five mud scows, proceeding down the Elizabeth river to the dumping grounds in-Chesapeake Bay, laid up during ihe night, owing to a high wind. In the morning the weather was clearing, the wind had abated, and the tug proceeded out into the bay. When near the dumping grounds the wind increased, the lines parted, and some of the scows were injured. ‘The weight of the evidence showed that there was no good reason to anticipate. dan- ger until it was too late to safely return. Held, that the tug was not liable for the damage to the scows. The FE. Luckenback, 1cg Fed. Rep. (U. S.) 487.