or over the decks. Dynamite boxes must be stowed topside up. Powder kegs should be loaded with seams up. 8. The term "high explosives in bulk” shall be construed to mean high explosives packed in boxes, barrels, or kegs and not loaded in ammunition or shells. The standard definition of the term "high explosives" will be that contained in paragraph 1503 of the regulations of the Interstate Commerce Commission for the transportation of explosives by rail, viz: "High explosives are all explosives more powerful than ordinary black powder, except smokeless powders and fulminates. Their distinguishing characteristic is their susceptibility to detonation by a blasting cap. Examples of high explosives are dynamite, picric acid, picrates, chlorate powders, nitrate of ammonia powders, dry trinitrotoluol, dry nitrocellulose (guncotton), dry tetranitroaniline, dry tetranitromethylaniline and fireworks that can be exploded en masse." Unless they are loaded in the same vessel with articles enumerated in the rule quoted above, picric acid 10 per cent wet, and trinitrotoluol 10 per cent wet, and nitrocellulose (guncotton) 20 per cent wet, will not be classified as high explosives. The term "high explosives in bulk" does not include such articles as benzol, toluol, smokeless powder, black powder, small-arms ammunition, ammunition for cannon with explosive projectiles, explosive projectiles or torpedoes, percussion fuses, time fuses, combination fuses, tracer fuses, cordeau detonant, primers for cannon and small arms, blasting caps, detonating fuses, and fulminate of mercury in bulk. Blasting caps, detonating fuses, and fulminate of mercury in bulk will be considered as constituting a distinct class by themselves, and must be stowed and handled with special care. 9. In transferring high explosives in bulk, blasting caps, detonating fuses, or fulminate of mercury from one vessel to another they must be handled by hand or regulation chute and mattress. If difference in elevation between vessels or condition of weather renders it impossible to transfer or load by hand or chute, mechanical hoists and a special crate or basket may be used. Explosives transferred in this manner must not be handled roughly. They must be hoisted and lowered carefully and be deposited or lowered on a mattress. 10. When an inclined chute is employed, such chute shall be constructed of 1-inch planed boards with side boards 4 inches high, extending 3 inches above top face of bottom of chute and throughout its length fastened with brass screws. D-shaped strips or runners not more than 6 inches apart and running lengthwise of the chute must be fastened to the upper surface of the bottom part by means of glue and wooden pegs extending through the bottom part and runners. Chutes must be occasionally wiped down with waste moistened with machine oil when dynamite packages are being handled. A stuffed mattress 4 feet wide by 6 feet long and not less than 4 inches thick, or a heavy jute or hemp mat of like dimensions, must be placed under the discharging end of the chute. The incline of the chute should be such that the velocity of the packages sliding will not be great enough to cause violent shock when coming in contact with other packages or when reaching the bottom of the slide, or men must be stationed alongside the chutes to retard the velocity of the packages and prevent violent shocks when packages come in contact with each other or reach the bottom of the chute. 11. Broken or seriously damaged packages of explosives may be recoopered when it is practicable and not dangerous. A broken box of dynamite that can not be recoopered should be reinforced by stout wrapping paper and twine, placed in another strong box, and surrounded by dry, fine sawdust, or dry clean cotton waste, or elastic wads made from dry newspaper. A ruptured can or keg should be inclosed in a grain bag of good quality and boxed or crated. Injured packages thus protected and properly marked may be forwarded. Packages too seriously damaged to be recoopered should not be forwarded, but set aside and the shipper notified to make disposition of them. In removing broken cases or kegs of explosives from vessels, care must be taken to remove any particles of loose explosives. 12. The transportation of high explosives by water and the transfer of high explosives to and from water craft in the harbor of New York and vicinity, other than in the case of naval vessels, shall be made under the direct supervision of such guards as may be assigned for the purpose by the captain of the port, but this is not to be construed as charging the captain of the port with any responsibility in connection with the navigation of such water craft. No high explosives in bulk shall be transported by water through Arthur Kill or Kill Van Kull, except that during stormy weather the captain of the port may permit, in his discretion, shipments of high explosives in bulk in amounts not ex ceeding 10,000 pounds in any one shipment to be transported through these passages when destined to explosive anchorage 49-B for local consumption: Provided, That no high explosives in bulk shall be transported through these passages at night or during foggy weather: Provided, That no other explosives shall be transported by water through Arthur Kill or Kill Van Kull except during stormy weather: And, provided further, That shipments of high explosives in bulk in amounts not exceeding 2,000 pounds in any one shipment may be transported through Arthur Kill or Kill Van Kull, except at night or during foggy weather, when such explosives are destined for local consumption at places along these two waterways. Owners or agents of water craft transferring or carrying such cargoes will be required to provide subsistence when crews are subsisted on board, and when necessary, suitable sleeping accommodations for guards placed on board by the captain of the port, and for such period as he may specify. When crews are not subsisted on board, subsistence for inspectors and guards will not be required, but every opportunity will be afforded to them to use such cooking facilities as are provided for the crews. 13. In any case of violation of the regulations in regard to the handling of explosives, the captain of the port is empowered to remove any vessel, or any man or men from the waters to which these regulations pertain or to stop the loading or unloading of explosives in said waters. 14. Nothing in the foregoing shall be construed as relieving the master of any vessels carrying explosives from the responsibility of making frequent inspections, by both day and night, to see that these rules are complied with. Approved by the Acting Secretary of War, June 4, 1930, with amendments to March, 1932. NAVIGATIONAL AIDS AND THE USE OF CHARTS The Coast and Geodetic Survey is charged with the survey of the coasts, harbors, and tidal estuaries of the United States and its insular possessions and issues the following publications relating to these waters as guides to navigation: Charts, Coast Pilots, Tide Tables, Current Tables, a catalogue of these publications and Notices to Mariners, the last named published weekly by the Bureau of Lighthouses and Coast and Geodetic Survey. Charts bear three dates, which should be understood by persons using them: (1) The date (month and year) of the edition, printed on the latest charts below the border in a central position; (2) the date of the latest correction to the chart plates, printed in the lower left-hand corner below the border; (3) the date of issue, stamped below the border and just to the left of the subtitle. Charts show all necessary corrections as to lights, beacons, buoys, and dangers, which have been received to the date of issue, being hand corrected since the latest date printed in the lower left-hand corner. All small but important corrections occurring subsequent to the date of issue of the chart are published in Notice to Mariners and should be applied by hand to the chart immediately after the receipt of the notices. The date of the edition of the chart remains unchanged until an extensive correction is made on the plate from which the chart is printed. The date is then changed and the issue is known as a new edition. When a correction, not of sufficient importance to require a new edition, is made to a chart plate, the year. month, and day are noted in the lower left-hand corner. All the notes on a chart should be read carefully, as in some cases they relate to the aids to navigation or to dangers that can not be clearly charted. The charts are various in character, according to the objects which they are designed to subserve. The most important distinctions are the following: 1. Sailing charts, mostly on a scale of approximately 1: 1,200,000, which exhibit the approaches to a large extent of coast, give the offshore soundings, and enable the navigator to identify his position as he approaches from the open sea. 2. General charts of the coast, on scales of 1: 1,400,000 and 1: 200,000, intended especially for coastwise navigation. 3. Coast charts, on a scale of 1: 80,000, by means of which the navigator is enabled to avail himself of the channels for entering the larger bays and harbors. 4. Harbor charts, on large scales, intended to meet the needs of local navigation. Note.-General charts of the Philippine Islands are on scales 1: 1,600,000, 1: 800,000, and 1:400,000; coast charts are on scales 1: 100,000, and 1:200,900. 161875°-33- -23 Coast Pilots, relating to surveyed waters of the United States, Puerto Rico, Virgin Islands, Alaska, Hawaiian Islands, and the Philippine Islands, contain full nautical descriptions of the coast, harbors, dangers, and directions for coasting and entering harbors. At intervals of about one year supplements are issued, containing the more important corrections since the publication of the volume. The supplements are printed on one side of the paper only, so that they may be cut and pasted in the appropriate places in the volume. Supplements and other corrections for any volume can be obtained, free of charge, on application to the Coast and Geodetic Survey, Washington, D. C., or any of its field stations, provided the volume itself has not been superseded by a subsequent edition. Tide Tables.-The Coast and Geodetic Survey Tide Tables are issued annually in advance of the year for which they are made and contain the predicted times and heights of the tide for each day in the year at the principal ports of the world, including the United States and its possessions. A table of tidal differences is given by means of which the tides at about 3,800 intermediate ports may be obtained. Beginning with the issues for 1934, tide tables will be published in two volumes; (1) Atlantic Ocean and (2) Pacific Ocean and Indian Ocean. In addition to the above, pocket edition tide and current tables are issued for Boston, New York, San Francisco, and Puget Sound. Current Tables are published separately as Current Tables, Atlantic Coast, North American, and Current Tables, Pacific Coast, North America, and Philippine Islands. These tables contain the predicted times of slack water and the times and velocities of strength of current in a number of important waterways together with a table of differences by means of which similar predictions can be readily obtained for numerous other places. Tidal current charts are published by the Coast and Geodetic Survey for Boston Harbor, New York Harbor, and San Francisco Bay. These publications show the direction and velocity of the current throughout the waterway for each hour of the tidal cycle. Agencies for the sale of the charts, Coast Pilots, Tide Tables, and Current Tables of the Coast and Geodetic Survey are established in many ports of the United States and in some foreign ports. They can also be purchased in the office of the Coast and Geodetic Survey, Washington, D. C., or any of the field stations. If ordered by mail, prepayment is obligatory. Remittances should be made by postal money order or express order, payable to the "Coast and Geodetic Survey." Postage stamps, can not be accepted. The sending of money in an unregistered letter is unsafe. Only catalogue numbers of charts need be mentioned. The catalogue of charts and other publications of the Survey can be obtained free of charge on application at any of the sale agencies or to the Coast and Geodetic Survey, Washington, D. C. Other publications.-Lists of Lights, including buoys and other daymarks of the United States, its insular possessions, and the Great Lakes are published by the Bureau of Lighthouses and may be purchased from its sale agencies or from the Superintendent of Documents, Washington, D. C. Notice to Mariners, relating to the same waters, is published weekly by the Bureau of Lighthouses and Coast and Geodetic Survey; this publication can be obtained free of charge on application to the Division of Publications, Department of Commerce, Washington, D. C. REMARKS ON THE USE OF CHARTS Accuracy of charts.-The value of a chart depends upon the character and accuracy of the survey on which it is based, and the larger the scale of the chart the more important do these become. In these respects the source from which the information has been compiled is a good guide. This applies particularly to the charts of the Alaska Peninsula, Aleutian Islands, Arctic Ocean, and part of Bering Sea, and the Philippine Islands. The early Russian and Spanish surveys were not made with great accuracy, and until they are replaced by later surveys these charts must be used with caution. With respect to these regions the fullness or scantiness of the soundings is another method of estimating the completeness of a chart. When the soundings are sparse or unevenly distributed, it may be taken for granted that the survey was not in great detail. A wide berth should, therefore, be given CHARTS 349 to every rocky shore or patch, and this rule should invariably be followed, viz, that instead of considering a coast to be clear unless it is shown to be foul, the contrary should be assumed. With respect to a well-surveyed coast, only a fractional part of the soundings obtained are shown on the chart, a sufficient number being selected to clearly indicate the contour of the bottom. When the bottom is uneven, the soundings will be found grouped closely together, and when the slopes are gradual fewer soundings are given. Each sounding represents an actual measure of depth and location at the time the survey was made. Shores and shoals where sand and mud prevail, and especially bar harbors and the entrances of bays and rivers exposed to strong tidal currents and a heavy sea, are subject to continual change of a greater or less extent, and important ones may have taken place since the date of the last survey. In localities which are noted for frequent and radical changes, such as the entrance to a number of estuaries on the Atlantic, Gulf, and Pacific coasts, notes are printed on the charts calling attention to the fact. It should also be remembered that in coral regions and where rocks abound it is always possible that a survey with lead and line, however detailed, may have failed to find every small obstruction. For these reasons when navigating such waters the customary sailing lines and channels should be followed, and those areas avoided where the irregular and sudden changes in depth indicate conditions which are associated with pinnacle rocks or coral heads. Dredged channels.-These are generally shown upon the chart by two broken lines to represent the side limits of the improvement together with the depth and date. The depth is the controlling depth through the channel on the date charted and does not mean that this depth obtains over the full width of the channel, nor that the depth has not subsequently changed due to either shoaling or dredging. Those changes are often of frequent occurrence; therefore, when vessels' drafts approximate the charted depth of a dredged channel local information as to conditions should be obtained before entering. 66 Danger curves.-The depth curves will be found useful in giving greater prominence to outlying dangers. It is a good plan to trace out with a colored pencil the curve next greater than the draft of the vessel using the chart and regard this as a danger curve," which is not to be crossed without precaution. Isolated soundings shoaler than surrounding depths should be avoided, as there is always the possibility that the shoalest spot may not have been found. Caution in using small-scale charts.-It is obvious that dangers to navigation can not be shown with the same amount of detail on small-scale charts as on those of larger scale; therefore in approaching the land or dangerous banks regard should be had to the scale of the chart, and the largest scale chart available should be used. A small error in laying down a position means only yards on a large-scale chart, whereas on a small scale the same amount of displacement means large fractions of a mile. For the same reason bearings to near objects should be used in preference to objects farther off, although the latter may be more prominent, as a small error in bearing or in laying it down on the chart has a greater effect in misplacing the position the longer the line to be drawn. Distortion of printed charts.-All of the Coast and Geodetic Survey charts are now printed by lithography on dry paper and have little if any distortion. A lithographed chart may be distinguished from a plate printed chart by the feel of the surface, the former being smooth while the latter is rough. Lithographed charts also are usually tinted in colors while the others are in black and white. Buoys. Too much reliance should not be placed on buoys always maintaining their exact position, especially when in exposed positions. It is safer, when possible, to navigate by bearings or angles to fixed objects on shore and by the use of soundings. Lighted buoys and other unwatched lights can not be implicitly relied on; the light may be altogether extinguished or, if intermittent, the apparatus may get out of order. Lights. The distances given in the Light Lists, Coast Pilots, and on the charts for the visibility of lights are computed for a height of 15 feet (4.6 m) for the observer's eye. The table of distances of visibility due to height, published in the Light Lists, affords a means of ascertaining the effect of a greater or less height of the eye. The glare of a powerful light is often seen far beyond the limit of visibility of the actual rays of the light, but this must not be confounded with the true range. Again, refraction may often cause a light to be seen farther than under ordinary circumstances. As the range of visibility increases with the elevation of the observer, it is often possible to obtain a bearing before the light is sighted from the bridge by sighting the light from aloft, noting a star in range with it, and then obtaining a bearing of the star with compass or pelorus. The actual power of a light should be considered when expecting to make it in thick weather. A weak light is easily obscured by haze, and no dependence can be placed on its being seen. The power of a light can be estimated by its candlepower as given in the Light Lists and in some cases by noting how much its visibility in clear weather falls short of the range due to the height at which it is placed. Thus a light standing 200 feet above the sea and recorded as visible only 10 miles in clear weather is manifestly of little brilliancy, as its height would permit it to be seen over 20 miles if of sufficient power. Fog signals. Sound is conveyed in a very capricious way through the atmosphere. Apart from the wind, large areas of silence have been found in different directions and at different distances from the origin of the sound signal, even in clear weather. Therefore too much confidence should not be felt as to hearing a fog signal. The apparatus, moreover, for sounding the signal may require some time before it is in readiness to act. A fog often creeps imperceptibly toward the land and is not observed by those at a lighthouse until it is upon them, whereas a vessel may have been in it for many hours while approaching the land. In such a case no signal may be sounded. When sound travels against the wind it may be thrown upward; in such a case a man aloft might hear it when it is inaudible on deck. The conditions for hearing a signal will vary at the same station within short intervals of time. Mariners must not, therefore, judge their distance from a fog signal by the force of the sound and must not assume that a signal is not sounding because they do not hear it. Taken together, these facts should induce the utmost caution when nearing the land or danger in fog. The lead is generally the only safe guide and should be faithfully used. In regions where the shores are high and rocky the echo of the whistle frequently gives warning of too close an approach to shore. In narrow passages it is often possible to keep in mid-channel by directing course so that the echoes from both shores are heard at approximately the same time. Tides. A knowledge of the tide, or vertical rise and fall of the water, is of great and direct importance whenever the depth at low water approximates to or is less than the draft of the vessel and, wherever docks are constructed so as to be entered and left near the time of high water. But under all conditions such knowledge may be of indirect use, as it often enables the mariner to estimate in advance whether at a given time and place the current will be running flood or ebb. In using the tables slack water should not be confounded with high or low tide nor a flood or ebb current with a rising or falling tide. In some localities the tide may be at a high or low water stand while the current is at its maximum velocity. The Tide Tables published by the Coast and Geodetic Survey give the predicted times and heights of high and low waters for most of the principal ports of the world and tidal differences and constants for obtaining the tides at all important ports. Plane of reference for soundings on charts. For the Atlantic coast of the United States and Puerto Rico the plane of reference for soundings is the mean of all low waters; for the Pacific coast of the United States and Alaska, and for the Hawaiian and Philippine Islands, it is the mean of the lower low waters. For the Atlantic coast of the Canal Zone, Panama, the plane of reference for soundings is mean low water, and for the Pacific coast of the same it is low-water springs. For foreign charts many different planes of reference are in use, but that most frequently adopted is low-water springs. It should be remembered that whatever plane of reference is used for a chart there may be times when the tide falls below it. When the plane is mean low water or mean lower low water, there will generally be as many low waters or lower low waters below those planes as above them; also the wind may at times cause the water to fall below the plane of reference. Tidal currents.-In navigating coasts where the tidal range is considerable, special caution is necessary. It should be remembered that there are indrafts |