D N K 



DOCK. 



I i 



_l is. that the ventilation should b* entirely under contn 

 the circulation of air be too rapid, a detsicmtion, and a consequent los. 

 ol weight, in the nunhuKiite would UkepUc; whilst, on the other 



hand, if the air were kept stagnant, tome claim of goodt would 

 deteriorate. 

 In docU more especially devoted to the purpoeen of the timber trade 



St. KatlwriM'i Docks. 



very different arrangement* are required fromfthose above deecribed. 

 A the ordinary baulk, fir timber, is supposed to improve by being kept 

 for a certain time afloat, the water surface of timber docks must be 

 made greater than usual, in order to allow the timber to be rafted. 

 The deals and planks require a considerable area for piling, but they 

 do not require any sheds; and the ordinary manner of unloading 

 them, namely, through ports in the bows of the ship, renders necc-s- 

 aary a trifling modification in the form of the quay walls. Mahogany 

 and fine furniture woods, however, require to be stacked under sheds, 

 and those of the West India Docks may be cited as models for this 

 claw of structure : they contain a aeries of moveable cranes, erected by 

 the late Mr. J. Ronnie, which might even now serve as valuable 

 leMons to engineers and machinists. 



It must be distinctly understood that the remarks above mode upon 

 UM practical details of dock construction, are made with reference only 

 to the circumstances of the day (1859) ; and it may be interesting to call 

 attention to some of the circumstances which have already modified to 

 a serious extent the technical Uws affecting these matters. Thus, the 

 West India and the London Docks were originally built at a time when 

 the existence of a state of war rendered it necessary for merchant vessels 

 to tail in convoys, and they frequently arrived in the Thames, under 

 those circumstances, in great numbers. It was therefore necessary to 

 make the water surface of the docks larger, in proportion to the develop- 

 ment of quay front, than would have been necessary in time of peace, 

 in order to be able to receive at once the whole fleets of a season. On 

 the declaration of peace, it was found that the basins were too wide, 

 and in some cases temporary jetties were run into them to increase the 

 berth room; but upon the inauguration of Sir R. Peel's free-trade 

 policy, the great water surface of these docks assumed a fresh value, 

 from the fact that vessels laden with corn, rice, and other grains ad- 

 mitted free of duty, were obliged to unload into barges in dock, because 

 the swell of the steamers in the open stream damaged the cargo. 

 Under all these ever- varying circumstances, it would seem, nevertheless, 

 that the most rational dimensions for parallel basins intended to receive 

 ordinary tailing ships are, that the width should be mode about from 

 600 to 600 feet, and the length about three or four or oven six times 

 the width. 



The entrance locks of the docks at London vary in width, according 

 to the traffic they are specially designed to accommodate, from 40 feet, 

 to as much as 90 feet in the case of the new Victoria Docks. For 

 ordinary shipping purposes a width of 48 feet, and a constant depth of 

 water of 23 feet over the cills will suffice, and the enonnoux width of 

 the Victoria Docks can only bo required for the reception of m 

 paddle-wheel steamers. The clear length between the points of the 

 gates likewise variu* between 100 and 800 feet; but the length of the 

 entrance to the East India 1>... k. 210 feet, seems to afford a very fair 

 average. As to the quay walls, they may be built either with a cur- 

 vilinear batter, in the style usually adopted by English engineers, or 

 with a straight batter, as upon the continent ; in both cases the versed 



sine is ascertained by making the average inclination equal to one in 

 eight. The various communication bridges should be made to open in 

 such a way as to interfere as little as possible with the rigging of the 

 ships moving in the docks ; and for this reason tummy bridges are 

 preferable to lifting bridges, or to those which are called batcvle bridges. 

 These remarks about the interference with the rigging will of course 

 apply throughout the whole details of dock construction ; and, indeed, 

 the injury which is often done to the masts and yards of vessels lying 

 in the St. Katherine's Dock, is one of the most serious objections to 

 the system of erecting the warehouses on the edge of the quays. 



The quay walla must be protected by means of fender piles to 

 prevent the ships from injuring the masonry as they rise and fall. A 

 very solid heavy coping must be placed on the walls; bollards, or 

 mooring posts, should be fixed at about every 50 feet apart ; and a 

 crane of about 5 tons power, and a water-cock or hydrant, placed at 

 distances of 200 feet apart It would be advisable, especially in a long 

 dock, to make occasional provision for a ladder or staircase to the 

 water's edge, in order to allow communication by boats between one 

 side of the dock and another. In docks where repairs of ships are 

 habitually executed, it may be necessary to devote a portion of the 

 water and of the quay surface to this purpose, and to provide thcar- 

 Icgi, uuutiny-tackk, yridiront or taMing-tumpi, with the necessary 

 furnaces for melting pitch and tar. Under all circumstances these 

 latter furnaces must be kept at a considerable distance from the vessels 

 in dock, and it is impossible to attach too much importance to the pre- 

 cautions to be observed for the prevention or for the extinction of fires. 

 In the most recently-constructed docks for the reception of the coal 

 traffic, the hydraulic lift has been largely employed ; and, indeed, it 

 has likewise been introduced in the working of the goods warehouses, 

 both of the London and of the Liverpool docks. 



Vessels entering docks, of course, do so under the direction of the 

 dock-master. There U at the entrances of the London Docks a clear 

 space left in the river (with a radius of 200 yards), where the companies 

 place dolphins, or hauling buoys, to facilitate the manoeuvres of the 

 vessels about to enter. A red flag is hoisted at the pier head win n it 

 is time for the vessels to prepare to come in, and a blue flag is hoisted 

 to show that the passage is free. Directly the ebb begins to make 

 strongly, the blue flag is struck : when this is done, no vessel is allowed 

 to enter until the next tide without a special order ; vessels coming in 

 have the precedence over those going out. All the manoeuvres attend- 

 ing the entrances of the ships are performed by their own crews ; and 

 the captains are bound to see that the anchors are ataught, the boats 

 on deck, the bowsprits run in, the yards set up and down, and gene- 

 rally that every precaution is taken to occupy as little space as possible. 

 The regulations with respect to fires, and tin' working of the ships in 

 dock, vary in every port; but, ae a ]>rii>< >{>!<, it ut admitted, that if 

 goods are to be warehoused, none but the workmen employed by the 

 dock authorities are allowed to touch them, under the inspection of the 

 Custom-House officers and of the captains of the ships. In the cose of 



