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THE CIVIL ENGINEER AND ARCHITECrS JOURNAL. 



[Feb. 10. 



GOVERNMENT CONTRACT FOR STEAMERS. 



Wf. have much pleasure in behig able to give a copy of the specification is- 

 sued by the Lords Commissioners of the Admiralty, on the 2(Jth of January 

 last, to the principal engineers, who are invited to contract for steam engines 

 jnr two nf Her Majesty's steam vessels of the first class and four of the second 

 class. Tlie tenders are to be delivered on the alh March next. It will be per- 

 ceived that the engineers are not limited to power, tlie object of Government 

 being to obtain as great a power as possible within the limit assigned for the 

 engine room, and within the limited weight. 



Specification of certain particulars to he strictly observed in the construction of 

 four pairs of marine steam engines, referred to in the Admiralty letter oj tlie 

 20th of Januar;/, 1844. 



For vessels vf the Second Class. 

 The tenders are to be made (in triplicate) on the accompanying printed 

 forms, every particular in which is to he strictly and carefully filled up ; and 

 all drawings, models, .and boxes containing them, are to be distinctly marked 

 witli the names of the parties transmitting them. The whole weight of each 

 pair of engines, including the boilers (with tbe water in them), the coal 

 bo.xes. paddle wheels, spare gear, the floor plates, ladders, guard rails, and 

 a!/ other articles, to be supplied under the contract, is not to exceed 300 tons. 

 N.B. If ihis condition is not strictly complied with, the contractor is to 

 fnr'eit £1000., or their Lordships are to be at liberty to reject the engines, 

 the manufacturers paying £1000. for the disappointment. 



The coal boxes (in the space of the engine room) are not to cont.ain less 

 than 350 tons, computed at 48 cubic feet to the ton, and more if possible. 

 Sufl'icient details of the coal boxes are to be shown in the drawing, to enable 

 a calculation of their contents to be made. In this computation, the space 

 below the deck to the depth of G in. is to be excluded, to allow for tbe space 

 occupied by the beams, and for the difficulty of completely filling the boxej 

 with coals. 



The consumption of coal per horse power, and the number of days' coals 

 ivhich tbe boxes will contain, are to be accurately stated in the tender. To 

 avoid the possibility of mistake in the dimensions given in the drawings 

 furnished to the respective parties, it is to be understood that 



feet, inches. 

 The length of engine room in the clear is .. 50 



Breadth of ditto 33 



Depth of ditto 21 



Centre of shaft above water line 8 9 



The horiz'-ntal situation of ditto as per drawing, or as near as can be. 



'Ihnsc tenders, however, which place engines of sufficient power in a space 

 less than 50 ft,, and give the largest stowage of coals, will be preferred. 



The holding down bolts are to be secured by nuts let into the lower sleep- 

 ers, so as not to require the bolts to pass through the vessel's bottom, and the 

 bolts are to have at the lower end of their points wrought iron washers 

 about Sin. square and 1 in. thick placed between the nuts and the wood. 

 Should this mode of security be inapplicable to the particular kind of engine 

 proposed, the engineer is fully to describe any other secure mode which he 

 may think the most advisable to adopt. 



The pistons are to be fitted with metallic packing. The blow oflT pipes are 

 to be 3.\ in. in diameter, and not less than J In. in thickness. 



Discharge or escape valves are to be fitted at the top and bottom of each 

 cylinder, for allowing the escape of water therefrom ; the valves to have 

 suitable metallic cases, to prevent danger of persons being scalded by escape 

 of boiling w aier, reverse valves are to be fitted to the boilers, and slop valves 

 at the ship's side to tbe waste water pipes. 



E.aeh cylinder is likewise to be fitted with a separate movement and valve, 

 for the purpose of using the steam expansively in various degrees, as may 

 from time to time be found eligible. The air pumps are to be lined with gun 

 metal of J in. in thickness wlien finished. Tlie air pump buckets are to be 

 of gun metal, with packing rings. The air pump rods are to be of gun 

 metal or Muntz metal, or of wrought iron cased with gun metal. 



The threads of all screwed bolts, nuts .and pins used in engines and 

 boilers, and in every other part of the work furnished by tbe contractor are 

 to agree with the threads used in the steam department at WoolHlch. 



A small engine is to be fitted capable of working one of the pumps for 

 feeling the boilers, in every case when the boilers are tubular. Pipes to be 

 fitted for supplying, in the event of a leak in the vessel, the requisite quan- 

 tity of Hater from the bilge to the condensers. 



The hand pump to be made capable of being worked by the engine also, 

 and to be arr.inged to pump into the boilers on deck or overboard, and to 

 draw water from the boilers, from the bilge, or from the sea. Tbe feed ap- 

 paratus to be complete, independently of any feed Irom a cistern above the 

 deck, should such b;' fitted. 



The steam jilpes and all other pipes to be of copper, and their respective 

 thicknesses and diameters to be specified in the tender. A separate d.amper 

 to be fitted to every boiler. Brine pumps, or some other equally efficient ap- 



paratus, with refrigerator, to be fitted to the boilers, and blow-ofi' pipes so 

 arranged, that any boiler may be blown off separately. 



A small flat Iron vessel to be fixed in one of the paddle boxes, with two 

 pipes, one communicating with the stoke hole, and the other with the boiler, 

 for obtaining a small supply of distilled water from the boiler. 



Air tubes to be fixed in the coal boxes, for ascertaining their temperature. 

 Particulars will be furnished to the contractors on application to the Captain 

 Superinlendant at Woolwich. 



The Boilers are to be of the tubular construction, anil the tender is to 

 specify the cost with Iron tubes, and with brass tubes respectively ; and it is 

 desirable that the up(X'r part should not be a greater distance above the water 

 line than circumstances render necessary. They are to l;e constructed in 

 three or more separate parts, each of which may be used independently of the 

 others. .Sufficient details of the boilers are to be shown, to enable a calcu- 

 lation to be made of the area of fire grate and of the fire and flue surface. 



A space of 13 in. wide is to be left clear between the boilers and the coal 

 boxes in every part. 



The paddle wheels arc to be of the common construction, and to be fitted 

 with suitable breaks. 



The tenders are to specify the highest power of engines which may be com- 

 liatlble uith the foregoing specification. The calculation is to be made, al- 

 lowing the effective pressure on each square inch of the piston to be 7 lb., and 

 the speed of the jilston — 



For 4 ft. stroke not to exceed 196 feet per minute. 



„ 4 6 „ „ 204 



„ 5 „ „ 210 



„ 5 R „ „ 216 „ 



„ 6 „ „ 222 



„ 6 6 „ „ 226 „ 



.,7 „ „ 231 



„ 7 6 „ „ 236 



„ 8 „ „ 240 



If any other than beam engines are [proposed they must be described veiy 

 minutely, with proper drawings or models. 



All the necessary ladders for the engine room, together with fenders, guard 

 rails, and floor plates, are to be included in the tenrler, and likewise the ex- 

 pense of trying and fitting the spare gear. It is to be understood that the prac- 

 tice of fixing new engines on board Her M.ajesty's vessels at Woolwich Dock- 

 yard Is to be entirely discontinued. The ports to which their Lordships will 

 lor the convenience of manufacturers allow vessels to be taken, are those of 

 London, Liverpool, Greenock, Glasgow and Dundee, provided the places at 

 which the vessels are to be in those ports sliall be named in the tender, and 

 approved of by their Lordships. 



In tbe case of vessels receiving their engines on board in the port of Lon- 

 don, they will in the fir;,! instance be brought to M'oolwlch ; and no 

 subsequent charge will be allowed for transporting the vessel to the place 

 where they are to be fixed on board ; for coals in trying the engines until 

 they are complete ; for boats, anchors, men, lighters, pilotage, canal or duck 

 dues, shipwright's work, or for any other expence whatever oecasioneil by 

 the engines not being fixed on board at M'oolwlch. The "watching" of 

 vessels is to be performed in future by officers and men in Her Majesty 's 

 service ; but no shipwrights will be provided by Government. 



In all cases ot vessels receiving their engines on board at any other port 

 than that of London, a deduction of 2 per cent, will be made from the price of 

 the engines named in the tender, as a compensation for the expense, wear 

 and tear, and risk thereby incurred. 



The expense of clothing (In tbe following manner) the cylinders, steam 

 pipes, and boilers. Is also to be included in the tender. 



The cylinders are to be covered with hair felt to the thickness of two 

 inches, the felt is to be covered with thoroughly dried wood, well fitted, and 

 bound together by iron or brass hoops. 



The steam pipes are to be clothed with felt, which is to be moulded with 

 spun yarn, and then to be covered with canvass, the whole to be of such 

 thickness as to be even with the flanches. 



After it has been ascertained by trial that every part of the boilers is per- 

 fectly tight, two good coats of red lead paint are to be put on them, and telt 

 aj'plied to the tops, sides, and ends, to the thickness of two inches, while tbe 

 paint is moist. 



For tbe more convenient application of the felt, it is to be previously 

 stitched to canvass for the purpose of holding it together. The canvass is 

 then to be well painted and carefully covered with thoroughly dried one inch 

 de.nl boards, having rabetted or grooved and tongued joints, and bound up to 

 the boilers with suitable iron stays. 



The coating of felt ami boards on the top of the boilers or steam chest is 

 to be kept at least 18 In. from tbe funnel, and the circular space between the 

 coaling and the funnel is to be covered with a 3 In. course of bricks set in 

 cement, and surrounded and held together by an iron hoop. 



The boards ami bricks on the upper pans of tbe boilers are to be covered 

 with sheet lead, 41b. to the sjuare loot, so as to prevent any leaks from the 

 deck reaching the felt. 



