Page:Encyclopædia Britannica, Ninth Edition, v. 17.djvu/289

N A V N A Y 277 Ex. 1. A ship bore N.E. 13 miles, steering S.S.E. 10 knots. Being nearly on a wind, which was E. byN., she could not alter course from her pursuer without loss of speed ; the pursuer being a steamship only able to go 9^ knots, if he allows the chase to cross his bows she will escape. Make a spot on the N.E. line, 13 miles from the centre, at A; place the parallel ruler to the course the chase is steering, S.S.E., and, with the distance representing her speed (10 knots) in the compasses, mark where it will reach on that bearing, from the ISLE, line to a position between the circles representing 9 knots, Fig. 23. which will be from a to b. Then a line from the centre through b shows the course the pursuer must take, S.E. by E. ^E., which continued will cross the S.S.E. line from A in E, where the vessels will meet. The distance and time of meeting may be measured on the diagram or calculated by trigonometry. The two ships will continue on the same relative bearings. Ex. 2. A point of destination bore V.S.W. 10 miles ; a current ran S.E. by S. 4 miles an hour ; the boat can pull at the rate of 6 miles an hour. It is convenient to consider that the object is mov ing in the opposite direction to the current and at the same speed. As the diagram is so small the proportionate speeds are doubled. Eight miles in the compasses will extend on a line parallel to S.E. by S. from the 12-mile circle at d to the W.S.W. bearing at/. A line from the centre through d will indicate the course to be steered, "W. by N. fN. From the point F on the 10 mile circle and S.S.W. bearing, a line drawn N.W. by N. will cut the former line in D, the place the boat would have reached had there been no current, 16 miles from the centre, occupying 2 n 40 m ; while DF represents the space through which the water has passed = 10^ miles in the same time. When a distant object can be seen in a line with the point steered for, and if the strength of the current be equal all the distance, the same bearing snould be preserved. As an example of crossing a river or channel where the tide will change at a known time, we may take that part of the Bristol Channel where it is 12 miles wide, say north and south, and the tide runs 5 knots. Suppose the boat can only pull 5 knots. By leaving one shore at an hour .and twelve minutes before high water, and steering directly north or south during 2 h 24 m , regardless of first being carried east and then west, the boat will reach its destination, having passed through 12 miles of water only. Though so much has been done to increase the efficiency of ships, in point both of size and of equipment, a sea voyage is still attended with considerable peril, both by stranding and collision. In the year ending April 1882 there were 4367 vessels damaged, including 606 total wrecks, with the loss of 1097 lives, round the coast of Great Britain alone. The number entering or leaving British ports during the same period was 676,358, of 139,443,790 tons burthen. The number of vessels at the same time above 50 tons under the English flag was over 22,000. Ships on long voyages were formerly content to make good one degree a day; now steamships occasion ally run 400 miles in one day. In September 1883 the "Alaska" (Guion Line) made the voyage from Qucenstown to New York in six days twenty-one and three-quarter hours, and returned in six days twenty-one hours. During the same month the "Oregon" made 20 knots an hour during her trial trip on the Clyde. The " Ionic" (White Star Line) arrived at Plymouth August 4, 1883, from New Zealand, through the Straits of Magellan, in forty-five days, includ ing stoppages for coal. Her passage out, round the Cape of Good Hope, was performed in forty-three days. This voyage round the world is the quickest yet accomplished, having occupied less than eighty-eight days at sea. In May 1883 the "British King" returned from performing a similar voyage, and discharging or receiving 6000 tons of cargo, in less than four months. Of late years, with the hope of diminishing the number of collisions, an international code of regulations has been drawn up by the Board of Trade and Admiralty, under the authority of the privy council, and sanctioned by nearly all maritime nations. The following is an abridgment of the law as now in force : Art. 1. Every ship under sail only is considered a sailing ship, but if any steam be used she is a steamship. Art. 2. The lights hereafter mentioned, and none other, shall be carried from sunset to sunrise. Art. 3. A steamship under way shall carry a bright white light before the mast at least 20 feet above the deck, a green light on the starboard side, and a red light on the port side. Art. 4. A steamship towing anything shall carry an extra bright light before the mast, i.e., two vertical lights. Art. 5. A telegraph cable ship at work, or others not able to steer, to carry three red lights vertically, and by day three balls. Side lights with the abovi-, only when making way through the water. Art. 6. Sailing ship under way. or being toweil, the green light on staiboard side, and red on port side only. Art. 7. Small vessels may carry portable lights similar to the above. Art. 8. All ships at anchor shall carry a white light, not exceeding 20 feet above the deck. Art. 9. Pilot vessels to carry a white light at the mast head only, and a flare-up every fifteen minutes. In lieu of Art. 10. Open fishing boats or other open boats may carry one lantern, green one side and red the other. Such boats when at anchor or fast to nets to exhibit a bright white light. Art. 12. Steamships must be provided with an efficient steam whistle, fog horn, and bell ; sailing ships with the last two. Turkish ships to carry a drum instead of a bell. a. In fog, mist, or snow, by day or night, a steamship must make every two minutes or less a prolonged blast. 6. A sailing ship at similar intervals with fog-horn to make one blast on starboard tack, two on the port tack, and three if the wind be abaft the the beam. c. All ships at anchor in a fog, &c., shall ring a bell every two minutes or less. Art. 13. Every ship in fog, &c., to go at a moderate speed." Art. 14. a. A ship running free shall make way for one which is close hauled. 6. Ships on the port tack make way for those on the starboard tack. c. Similarly if running free. d. When running free with the wind on the same side, the ship which is to windward shall keep out of the way. e. A ship which has the wind aft shall keep out of the way of any other. Art. 15. If two steamships are meeting nearly end on so as to involve risk, they shall both alter course to starboard. Art. 16. When two steamships are crossing, the one which has the other on her port side is to keep out of the way. Art. 17. A steamship shall keep out of the way of a sailing ship. Art. 18. Steamships shall slacken speed, stop, or reverse if necessary. Art. 19. Optional signals by the steam whistle: one short blast means, "I am altering course to starboard"; two short blasts, "I am going to port"; three short blasts, "I am going full speed astern." Art. 20. When one ship overtakes another, the faster ship is to keep out of the way. Art. 21. In narrow channels ships shall keep on the starboard side. The books on navigation in general use are those of Norrie, Inman (especially his tables), Kiddle, Raper, Jeans, and Evers, and Harbord s Glossary. (H. A. M.) NAVIGATION LAWS. These laws are a branch rather of municipal law than of the general maritime law (for which see SEA LAWS). They are based upon the right of a state to regulate the navigation of its own waters and to protect its own commerce, and may be divided into two classes. The first class includes all those laws, once so numerous, designed to secure a commercial monopoly to the state which enacted them. By laws of this kind trade with Goa was formerly confined to Portuguese subjects. In Great Britain the object was attained by the Navigation Acts, the earliest of which were the 5 Rich. II. stat. 1, c. 3, 14 Rich. II. c. 6, ordaining that no merchandise should be shipped out of the realm except in British ships on pain of forfeiture. The principal Navigation Act was the 12 Car. II. c. 18 (Scottish, 1661, c. 45). Up to 1854