1840.] 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



.349 



ing there is no keel, altlKaisli tlic lo^^"er plate of iron, wliicli connects the 

 two sides of the ship, and which is ahout a foot in breadth, is called the keel- 

 plate. This plale is slightly cm'vod. with its conve.K side downwards, so as 

 to form a channel for water in the direction of the length of the vessel, under 

 the tloors. The floors are straight bars of angle iron, with one flange, four 

 inches wide, lying horizontally ; the other 9 inches deep, hanging vertically. 

 The vertical flange is connected to the bottom-plates of the ship by 3-inch 

 angle iron — that is, angle iron of 3 inches width of flange. Upon the npper 

 surfaces of the floors, iive ranges of sleepers, of timber 12 inches square, and 

 extending the whole length of the hold of the ship, are laid, and securely 

 bolted to the horizontal flans^es of the floors, by 1 -inch bolis, their poin:s 

 secured umhr the flange of the floor by imts on to screws at these points. 

 The frames, which are of angle iron 3 inclies wide, are 18 inches apart along 

 the midship body of the vessel ; but forward and aft this space is gradually 

 increased, until they become about three feet apart. The in and out flaiif^e 

 of the frames is rivetrd to tlie vertical flange of the floors by J iron rivets, 

 about 6 inches apart. The iron plates foiming the planking, or rather skin, 

 of the vessef, are secured to these frames by being riveted to the other flange 

 of the frames with rivets of j iron, which are distant apart about 3 inches 

 from centre to centre. 



The connection of the sleepers or keelsons, which are of red-pine timber, 

 with the iron floors, and of the floors with the frames, and of the iron plates 

 with the.se frames, may be more easily understood by reference to 

 Fig. 1. The rivets by \\hich the plates are secured to the frames, are luit in 

 from the inside of the vessel, and are clenched flush on the plate : the outer 

 part of the hole through the plate being counter-sunk to receive the rivet, so 

 tha! the bottom of the vessel is a perfectly even and smooth .surface. Tlie 

 whole of the riveting is pcrforineu with rivets heated nearly to a welding 

 heat; therefore, the contact between the surfaces of the iron is exceedingly 

 perfect, as it is insured not only by the care applied to the riveting, but by 

 the contracting of the rivets in cooling. The frames run up to and end upon 

 the iron gunwale, which h;'s been before mentioned. This is of 3-inch angle 

 iron, with one flange horizontal, to which the 4-inch wooden giinwale is 

 secured by screw-bolts: the other- flange is vertical, and to that the upper 

 ends of the frames are riveted. Between the wood and the iron forming this 

 compound gunwale, felt is laid, which is so firmly compressed by the screw- 

 bolts, that the joint is perfectly water-tight. The beams are of iron, and 

 formed by two bars of angle iron, having their vertical flanges back to back, 

 with a bar of iron 9 inches deep and \ of an inch thick riveted between these 

 two vertical flanges. The deck is of fir, 3 inches thick, lying upon an I being 

 secured down to the horizontal flanges of the beams by screv.- bolts, the heads 

 of which are sunk about J an inch Ijelow the surface of the plank, and are 

 hidden by plugs driven down upon them v. ith white lead. Thus the fasten- 

 ings of the deck are scarcely perceptible. The points of these bolts .are se- 

 cured beneath the horizontal flanges ot the beams by nuts on a screw. I he 

 connection of the angle-iron gunwale with the wooden gunwale and with the 

 planking i also, the connection of the deck with the beams, and the method 

 of forming the beams, will be more easily understood by the following 

 sketches : (Figs. 2 and 3.) 



Fig. 3. — Section of beam. 



r?!?-i. 



z 



p < 



Fig. 4. 



f^n 



o -y-o 6^ 



T 



^^^■■ 



Fig. 2. 



Reference— Fig. 1. — S, sleeper, 

 iron plate. fF, frame between. 



Figs. 2 &.'3.— D, deck. B, beam, 

 frame. 



Figs. 4 !!^ 5.— R, rudder. P, port, 

 stern. 



Fig. 5. 



The ends of the beams are secured to the sides by angle-iron knees. The 

 paddle-beams, which, it has been before said, are of timljcr, pass the sides of 

 the vessel through what may be called sockets, formed by bars of angle iron 

 placed above, below, and on each side of them. One flange of each bar is 

 firmly riveted to the planking o' the vessel ; and the other flange is secured 

 to the beam by screw bolts. Felt is also inserted here in the joiijts between 

 the wood and iron. This appears to be a general precaution in similar con- 

 nections. 



The stem is formed of sheet-iron, in the same manner as has been alread^ 

 described for the keel. At the lower part of the stem there if a sort of '"^ 

 soA'et of iron, which forms the gripe, and in which the lower end of the 

 wooden knee of the her.d is inserted. It has been already mentioned that the 

 rudder of the Nemesis is of tinil er ; but this appears to be an exception to 

 the general practice in th?se iron vessels. The main piece inclusive of the 

 head, is usually of iron ; and when of iron, is thus formed and connected 

 with tlie stern-pcst. (Figs. 4 and !>.) 



The s ern is strengthened by a fasliion-piece of angle iron: and the tie 

 across the stern is by a transom, also of angle iron. The berthing all round 

 the vessel, already mentioned :^s being of fir, is secured to short fop-timbers 

 of wood, which are let through the gunwale and run do',\n about two feet 

 below It. They are secured by two riveted bolts through the planking of the 

 vessel ; and at their intersection with the iron gunwale, by angle iron on each 

 side. 



The sheets of iron which form the planking of the vessel are about 8 feet 

 long anil 2 feet 6 inches broad. Of cou se, these dimensions vary according 

 to the place of the sheet in the body of the vessel. The lowerGsirakes ivhich 

 form the bottom, and extend from the keel-pl ite to the turn of the bi'ge. are 

 clinker-tui t. The stnke at the turn uf the bilge, and the 5 strakes which 

 form the side of the vessel from this turn upw.irds, are carvel-built. The 

 lands of the clinker seams are riveted with f iron rivets similarly to the lands 

 of a clinkcr-ljuilt boat, without any strengthening bands. The carvel seams, 

 and the buts of b^th clinker and carvel strakes. are secured by bringing the 

 edges of the plates in contact, and riveting each edge to a strip of puate-iron, 

 lying on and linir.g the inside of the j int. The scams arc caulked by closing 

 the edges of the two plates tcge'.lier with blows of a cold chisel. The whole 

 of the rivets are flush on the outsiile of the vessel. The keel-plates are 

 7-16ths of an inch in thickness. The clinker-worked plates covering the 

 bottom of the vessel are Jihs of an inch in thickness ; and the carvel-w; rked 

 pi ites, covering the top-sides, are from 5-16ths to J of an inch in thlcknes.'. 

 The irrii work is first painted wiih several coats of red lead, and then var- 

 nished with a patent varnish. This covering to the iron did not appear to 

 beat all disturbed on any part of the botttm excepting where it had been 

 itibbcd ofl by the rocks on which she had grounded. 



There are several peculiarities in the internal arrangements of the vessel. 

 The whole internal space is separated into seven water-tight compartments, 

 by six iron alhwar'ships bulkhe.ul .* Four of lhe;e — those in the wider part 

 of the vessel — are of ,5-161113 of an inch iron. The bulkhead nearest to each 

 extremity, be'ng of small surface, .and liable to less immersion, is only 3-lUths 

 in thickness. Ihe wooden sleepers necessarily pass through e'.ch of these 

 bulkheads, and they are secure,! where they pass through by strong flanges 

 bolted down to them over felt, and riveted to the bulkheads, so that no water 

 can possibly pass from any oiu' compartment to the other. Therefore, a leak 

 v. hich may be sprung in any part of the bottom of the vessel, can only anect 

 that compartment between' the bulkheads of which it happens. Thus tie 

 damage caused by the rock on which she struck, admitted 4 feet of water in'o 

 the compartment in which it occurred, before the leak could be stopped, but 

 there was none in any other part of the vessel. There is trsmall hand-pump 

 fitted to each compartment, the pipe from which leads into the hollow of the 

 keel-plate. Large pumps are not necessary, as the compartment can only 

 fill to'^the level of the ex'ernal water, and may then be emptied at leisure; 

 or, if the leak be gre:Uer than the discharge of the pump, may remain filled 

 until a port is reached. 



In the space between the engines and the boilers, usually called the stoke- 

 hole, there is a very ingenious means adopted to strengthen the b-idy, with- 

 out interfering with the accommodations of the engine-room. Tliis is the 

 introduction of a partial bulkhead with an aperture bounded above by an 

 erect, and below by an inverted arch of bar-iron ; thus supplying by me- 

 clnnicnl contrivance ihc support which otherwise could not be obiained for 

 this part of the body, without great inconvenience. To obviate the disad- 

 vantages atendant on the small draught of water which this vessel diaws, 

 there are two sliding keels, similar in jirincip'eto Iho^e which were originally 

 proposed by Capt. .Shank, of the Royal Navy, when in command if the 

 British force on the American Lakes, during tlie War of Independence. These 

 keels are each 7 feel long, and capable of being protruded 5 feet below the 

 keel of the vessel. They are of wood, -ll inches thick, and each w orks up 

 and down by means of a small windlass and an endless chain, in a water- 

 t ght case or trunk 12 inches wide, formed like the rest of the bvdkheads. of 

 sheet iron, and running from the bottom of the vessel up to the deck. The 

 plates of these trunks are 7-16ths of ,an inch thick, and they are strongly 

 secured by angle iron to the athwartship bulkheads, which they also serve 

 to support. 



The report of the officers on the advantage which they derived from these 

 keels, when under sail, in enabling them to keep the vessel up to windward, 

 and in keeping her steady, is very lavourable. In fact, they are an ingenious 

 modification of ihe lee-board. One of them is situated jist before the engine- 

 room, and the other just abaft it. There is also a contrivance by which the 

 depth of the rudder in the water may be increased whenever these sliding 

 keels are used. 



Having now described the vessel, we will proceed to descrilie ihe damage 

 she sustained by striking. When she struck, her sped is reported to have 

 been nearly 9 knots : her average speed was 8i. The first blow was evident!/ 

 received exactly in the centre of tlie front of the fore-foot or gripe, which 

 was dented in' about 3 inches, and split about S inches in its length. This 

 blow must have been inflicted by a rock at least as sharp as the pea of a mo- 

 derate sized anchor. The blow appears to have been repealed under the keel- 



* \V"e have been told that this method of dividing the whole length of a 

 vessel into separate water-tight comparlments is adopted in all sea-going 

 Chinese junks. We trust uur naval men engaged in those seas will keep their 

 eyes open to these and many other interesting particulars respecting the 

 Chinese vessels — for a description of which our pages shall alw ays be open. — 

 Editor. 



