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BUOY structure on a broad face shall be called pillar buoys (Fig. 4), and like all other special buoys, such as bell buoys, gas buoys, and automatic sounding buoys, shall be placed to mark special positions either on the coast or in the approaches to harbours. (7) Buoys showing only a mast above water shall be called spar buoys1 (Fig. 5). (8) Starboard - hand buoys shall always be painted in one colour only. (9) Porthand buoys shall be painted of another characteristic colour either single or particolour. (10) Spherical buoys (Fig. 3) at the ends of middle ~ ~ ~

. ~ grounds shall always g be distinguished by horizontal stripes of white colour. (11) Surmounting beacons, such as staff and globe and others,2 shall always be painted of one dark colour. (12) Staff and globe (Fig. 1) shall only be used on starboard-hand buoys; staff and cage (Fig. 2) on porthands ; diamonds (Fig. 7) at the outer ends of middle grounds; and triangles (Fig. 3) at the inner ends. (13) Buoys on the same side of a channel, estuary, or tideway, may be distinguished from each other by names, numbers,

or letters, and where necessary by a staff surmounted with the appropriate beacon. (14) Buoys intended for moorings (Fig. 6) may be of shape or colour according to the discretion of the authority within whose jurisdiction they are laid, but for marking submarine telegraph cables the colour shall be green, with the word “ Telegraph ” painted thereon in white letters. Buoying and Marking of Wrecks.—(15) Wreck buoys in the open sea, or in the approaches to a harbour or estuary, shall be coloured green, with the word “ Wreck ” painted in white letters on them. (16) When possible, the buoy should be laid near to the side of the wreck next to mid-channel. (17) When a wreckmarking vessel is used, it shall, if possible, have its top sides coloured green, with the word “ Wreck ” in white letters thereon, and shall exhibit by day, three balls on a yard 20 feet above the sea, two placed Fig. 7. vertically at one end and one at the other, the single ball being on the side nearest to the wreck ; in fog, bell and gong in quick succession at intervals not exceeding one minute (wherever practicable) ; by night, three white fixed lights similarly arranged, but not 1 2

Useful where floating ice is encountered. St George and St Andrew crosses are principally employed to surmount shore beacons.

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the ordinary riding lights. (18) In narrow waters or in rivers and harbours under the jurisdiction of local authorities, the same rules may be adopted, or, at discretion, varied as follows :—When a wreck-marking vessel is used she shall carry a cross-yard on a mast with two balls by day, placed horizontally not less than 6 nor more than 12 feet apart, and two lights by night similarly placed. When a barge or open boat only is used, "• a flag or ball may be shown in Single Colour Vertical Stripes the daytime. (19) The posiFig. 8. Fig. 9. tion in which the marking vessel is placed with reference to the wreck shall be at the discretion of the local authority having jurisdiction. A uniform system by shape has been Chetfuered Horizontal Stripes adopted by the Mersey Dock Fig. 10. Fig. 11. and Harbour Board, to assist a mariner by night, and, in addition, where practicable, a uniform colour; the fairway buoys are specially marked by letter, shape, and colour. British India has practically adopted the British system. ITnited States and Canada have the same uniform system; in the majority of European maritime countries and China various uniform systems have been adopted. In Norway and Russia the compass system is used, the shape, colour, and surmountings of the buoys indicating the compass bearing of the danger from the buoy; this method is followed in the open sea by Sweden. An international uniform system of buoyage, although desirable, appears impracticable. Germany employs yellow buoys to mark boundaries of quarantine stations. The question of shape versus colour, irrespective of size, is a disputed one; the shape is a better guide at night and colour in the daytime. All markings (Figs. 8, 9, 10, and 11) should be subordinate to the main colour of the buoy ; the varying backgrounds and atmospheric conditions render the question a complex one. Trinity House buoys are divided into five classes, their use depending on whether the spot to be marked is in the open sea, or in an otherwise exposed position, or is in a sheltered harbour, or according to the depth of water and weight of moorings, or the importance of the danger. Buoys are moored with specially tested cables (see Cable) ; the eye at the base of the buoy is of wrought iron to prevent it becoming “ reedy,” and the cable is secured to blocks (see Anchor) or mushroom anchors according to the nature of the ground. Trinity House buoys are built of steel, with bulkheads to lessen the risk of their sinking by collision, and with the exception of bell buoys, do not contain water ballast. In 1878 gas buoys, with fixed and occulting lights of 10 candle power, were introduced. In 1896 Mr T. Matthews, engineer-in-chief to the Trinity corporation, developed the present design (1901) (Fig. 12). It is of steel, the lower plates being -f in. and the upper in. in thickness, thus adding to the buoy’s stability. The buoy holds 380 cubic feet of gas, and exhibits an occulting light for 2533 hours, 10 feet above the sea, and is visible 8