300 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



[August^ 



termine, witli sufficient aceiiiacy, either the area of tlie safety-valves, eom- 

 |)ared with the power of the Ijoiler, or tlie pressure at which tiip explosion 

 took place. In the event of a coroner's inquest, these important facts are 

 rarely iiupiireil into ; it is nu one's business to asecrtain them ; jurors unilcr- 

 stand nothing about the matter, and are mystified by eonti'adictory state- 

 ments. In several of the cited cases, the sjjindlcs of the valves bad been 

 bent, or otherwise set fast ; in that of the " Morning Star," though tlie valve 

 rose, and allowed some of the steam to escape, we are informed by Mr. 

 Greener, who examined the boiler minutely, ami gave evidence on the inquest, 

 *' that it was .w runted, it appeared not to linee acted for years.'^ Its area 

 was also Tei*y inadequate, having only about one square inch of ai)erture to 

 four-horse power ; the engineers of tlie Thames steamers usually give an area 

 to their safety-valves of one square inch for each horse power— a safe ajul 

 excellent practice ; but we found the dimensions of safety-valves so restricterl 

 in the vessels of some ports, that only one-fifth of a sqviare inch was allowed 

 to each horse power, an area so insuthcient, that though the valves might be 

 well made, and act freely, tlie pressure of steam would continue to increase 

 when the engine stojiped, ami attain an elasticity exceeding the resistance of 

 the boiler, though steam were continually escaping. Au explosion is the 

 necessary consequence. 



Height of IJ'ater in the Boilers. — It is also difficult to obtain, after these 

 accidents, crediltle information as to the sutBciency of water in the boilers, at 

 the moment of explosion. It is probable — from the general absence of glass 

 water-gauges, in the class of steamers whose boilers have chiefly exploded — • 

 that testimony on this point is not to be relied upon. The " Union's " in 

 a clear ease of deficiency of water, combined with overheated flues, and an 

 oscillatoiy movement of the vessel. A simple contrivance to assist in ascer- 

 taining the true level of the water in a boiler, is descrilied by Mr. Golightly. 



Qiiulity of tlie Metal of Boilers. — Some veiy intelligent remarks will be 

 found in Mr. Greener's replies to our (|ueries, on the important subject of the 

 quality of iron used for boilers ; a subject whicli is far from occujiying the 

 attention it merits either by hoiler-niakers, engineers, or steam-vessel owners. 

 A piece of the " Morning Star's " boiler, in our possession, taken from the 

 ruptured part, shows it to have been corroded to two-tenths of an inch in 

 thickness, its original strength having been half an inch, and the iron very 

 bad. The fire-tube ruptured at a pressure of about 231bs. per square inch ; 

 its form was elliptic, three feet, by two feet six inches ; the external shell, 

 cyliudric, 6 feet diameter. 



Fires. — The chaning of timbers iii the wake, or proximity, of the boilers, 

 is alluded to by the ship-builders, and many other correspondents, as a fre- 

 quent cause of fire and injury to the vessel. 



We here beg to draw jiarticular attention to the excellent arrangements 

 and practice adopted by the City of IJublin Steam Packet Company of Liver- 

 pool, and in well-appointed vessels of other comiianies, to obviate the evils 

 arising from these fertile sources of danger to the vessel, and of expense to 

 the omiers. \Ve refer to their use of iron beams and deck jilates over the 

 boilers, and about the funnel ; of the complete se]iaration of tlie boilers from 

 each other, and from the sides of the ship ; of lining the ship's sides with 

 lead, covered again with iron, in the proximity of the boilers ; of protecting 

 the boilers from spray, rain, and the contact of coals, by a shell of iron ; and 

 the practice of sweeping down all the remaining coal into the bunkers, or 

 iron coal-boxes, on the termination of each voyage. 



The suggestions also of Messrs. Maudsley and Field, and others, that pipes 

 from the boilers should be so arranged as to convey steam into the coal re- 

 ceptacles, and other parts of the vessels, in the event of fire, would give great 

 additional security. 



Collisions. — Collisions between steam-vessels, and between them and other 

 craft, occur so frequently in crowded waters, they are often so fatal to life, 

 and so generally attended mtli litigation, and expense in repairing damage, 

 that the want of a law to diminish the evil, is tlie subject of complaint by 

 nearly all our correspondents. Collisions occur both by day and by night, 

 at sea as well as in rivers. They commonly arise from the absence of an 

 universal understanding as to the "rule of the road" to be observed by ves- 

 sels, in meeting and passing each other, and from the absence of an universal 

 system of niijht-tifjhls or signals. 



The practice is at present regulated only by custom, or by the bye-laws of 

 different ports, which custom, being various, is productive of serious collisions 

 even on the high seas. 



The same causes which produced the first collision remain still in full 

 activity, and it is fearful to eontemplate the loss of human life which the 

 absence of a law on these subjects may produce at any moment. 



There is yet another important point to be considered, as bearing on the 

 means of preventing collisions. 



A distirxjiiislmii/ sound should be provided on board steam-vessels, as an 

 alarm, to notify their proximity to other vessels at night, on occasion, but 

 more particularly during fogs or thick weather, when lights can only be seen 

 on a very near approach. The want of such regulation is alluded to by 

 several of our correspondents, and a means is also suggested for accomplishing 

 the end. Sailing-vessels are generally provided with some instrument for 

 making a noise, to which resort is bad when circumstances require it ; viz. 

 bells, horns, gongs, &e. A steam-vessel carries with it an agent more jiower- 

 ful than any of these contrivances, and one which could not fail in notifying 

 its approacli, distinctively from every class of vessel, and from a much greater 

 distance than bells, &c. ; a circumstanee of no slight eonsequence, when the 

 greater velocity of a steamer is considered. Tlie sleam-vliislle in common 



use, attached to locomotive engines, if apjilied to the boiler of a steam-vessel, 

 would completely fulfil the desired end. All that is required is a small pijie 

 opening into the steam-chest, and brought up on deck, with the wbistle on 

 the top of it, in a convenient position to be used when the commander inav 

 order it. lly simjily turning the hanille of a cock, a iirolonged sound is |iio- 

 duced, or a succession of sounds, on opiMiing and shutting the cock at short 

 intervals. The sound from the whistle of a locomotive engine has frequently 

 been beard more than two miles. We have made particular inquiries as to 

 the degree of sound producible mtli low-iiressnre, compared with high-pres- 

 sure steam, and learn that this wliistle may be constructed so as to be e(|iially 

 as effective with the one as witli the other. 



BOILERS AND ENGINES. 



Boilers. — That boilers are very frequently continued in use till they become 

 dangerously thin, and that they are frequently deficient in safety a|iparatns, 

 is a fact not only evidenced by the Table of Explosions, and instanees given, 

 but attested by a large majority of our correspondents. We were sliown 

 several in the yards of engine and biiiler-makers, which (to use their own 

 expression) " might be walked tbrougli ; " indeed, the liaml might be pushed 

 tbrougli some boilers which we examined, but recently taken out of steam- 

 boats. Mr. Shaw states th.at " the boilers of the ' Fingal,' in 183.^, were so 

 weak that they had to be shored between the deck and tlie tojis of them, 

 which exjiauded and contracted like a pair of bellows." Captain iiaiu «Tites 

 that " he has frequently bad occasion — sometimes under very trying circum- 

 stances — to stop rents in boilers by temporary expedients; that he has wit- 

 nessed it in other vessels, and has seen boilers worked till they were as thin 

 as paper, &c." Some boilers, in actual use, are only kept tight by the ile- 

 posit of niml, concretions of salt and sand, Ac. between the flues ; these 

 obstructions to the passage of heat are not removed, as the metal of the 

 boilers would give way, and they must then necessarily umlergo repair, w Inch 

 is delayed till they will no longer hold togelher, or till nqitures occur, and 

 have produced misebief. The Appendix contains, in the rejilies to our .'>tli 

 query, aliundant testimony to negligence, and ill-judged economy of this 

 nature. 



The explosion of deteriorated boilers, is not the greatest disaster to be 

 dreaded from steamers so ill provided ; under the head of Wrecks and Foun- 

 derings, the ealaniitous consequences of boilers failing at sea, are still more 

 fearfully exemplified. 



Nearly the whole of the passenger, and no inconsiderable portiini of the 

 merchandize, coasting traffic of the British Isles, is carried on by steam-vessels, 

 the rapidly increasing number of which will presently be shown. It is iiii- 

 ])OSsible to determine, in the absence of official record, whether the nnmlier 

 of accidents has increased in a greater ratio than that of the steamers; but 

 our schedule exhibits an annual increase of disasters, and shows tli.at nearly 

 the half of them has occuiTed within the last three years ; and that from the 

 beginning of 183S to the present time — a period of 15 months only — no 

 fewer than 22 accidents have happened. They consist of — 



11 WTCcks, founderings, or imminent peril ; 117 lives lost. 

 8 explosions . ... - 20 ditto, and many persons 



injured. 

 2 collisions ..... — 

 1 fire — 



22 137 



In addition to the amount of human life sacrificed, 038 animals were 

 thrown overboard, or scalded to death. 



Seven of the vessels were totally lost, four of which are traced to have 

 had defective boilers, or engines ; and others had to undergo costly repairs. 



It results from the opinions expressed by the engineering class of our cor- 

 respondents, that great additional safety is obtained by employing several 

 boilers, distinct from each other, rather than one only, or two boilers con- 

 nected together ; many dangers are avoided by this method. Independently 

 of the obvious security arising from the means, thus afforded, of shattiiif/ off 

 a disabled boiler, and even of repairing it, whilst the motion of the engines is 

 continued by the others, this arrangement jiossesscs many other advantages, 

 and cannot be too strongly recommended for general adoption. Mr. Shaw 

 gives a forcible illustration of the value of distinct boilers, in his account of 

 the salvation of the "Thames," after her perilous collision with the " Shan- 

 non." 



Engines. — The machinery by which a steam-vessel is projielled appears, 

 notwithstanding its comparative complexity, to be maintained, generally, in 

 better condition than the boilers. The foundering of the "Venus" in 1829 

 is an instance of a disaster occasioned by the breaking of the connecting rod ; 

 the more common derangements are fractures of cross-heads, beams, cranks, 

 crank-pins, lie, of which we both saw and heard many examples ; but the 

 practice of using a pair of engines, iiarticularly in sea-going steamers, is a 

 great guarantee against shipwreck, as, in the event of one engine being dis- 

 abled, the other can safely work the vessel. IJuplieatcs of the parts most 

 Uable to fracture, should always he found amongst the stores of a steamer. 



Several wrecks have been referred to liy our corrcsiiondents which might 

 have been averted, had the paddle-wheels been furnished with dismyar/inr/ 

 opparalns, which is eflfected too slowly, and clumsily, by removing the floats — 

 an operation, also, difficult of .accomplishment in tempestuous weather. Ilri- 

 fish engineers are not likely to leave so great a desideratum long unsupplied; 

 several jilans for its accomplishment are already in partial use. 



