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THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



[January, 



ON VENTILATION OF SHIPS. 



Suggestions for the better Ventilation of Sailing and Steam Vessels. By 

 Robert Ritchie, Esq., F.R.S.S.A., &c, C.E., Edinburgh. 



(Abridged from a paper read before the Royal Seottish Society of Arts, April 10' 



1843, and reported in their Transactions. Illustrated by Diagrams ami 



Models.) 



The ctimmencement of the paper is occupied with a history of the various 

 contrivances and means proposed for ventilating ships from 'the year 1741 

 to the present time. 



The failure, however, of so many ingenious schemes, extending over so 

 many years, for improving successfully the ventilation of ships, has tended 

 very strongly to impress me with the idea, that any method to be extensively 

 useful, especially as regards sailing-vessels, must enter into the original con- 

 struction of ships. And with this view I would suggest the introduction 

 into timber and iron-built ships, of a thorough and efficient system of spon- 

 taneous or self-acting ventilation, affording at all times an ample supply of 

 fresh air in every part of a ship, by means of a judicious arrangement of 

 air-flues in the former, and pipes in the latter. In a large class of vessels 

 ow afloat, hy application of the openings or interstices between the timbers 

 (presently in use for airing the frame-work.) where the plan of close timbers 

 has not yet been adopted, a free circulation of air might be effected at all 

 times in lower-decks and cabins. As regards the airing of the frame-work 

 itself, its importance has long been a point of much interest for the preser- 

 vation of the parts below the surface, though much difference of opinion 

 among practical men Is entertained on this point, one class advocating a free 

 circulation of air about the timbers, and another the exclusion of air. ' In 

 a communication to the Royal Society of London in 1820, by Sir Robert 

 Seppinga, F.K.S., wlun giving suggestions for a new principle of construction 

 of ships for the mercantile navy, he alludes to the ventilators of Dr. Hales, 

 and the utility of general ventilation, but attaches importance to the exclu- 

 sion of atmospheric air for the preservation of the frame-work, though he 

 was not inattentive to the value of admitting air to the interior of ships. 

 Another view is taken of this subjpet in the able treatise on ship-building in 

 the Encyclopedia Brittaunira. where the suggestion is made that the preser- 

 vation of the timbers might be assisted by ad. pting the openings between the 

 timbers themselves, for the purpose of circulating air about them ; and it is 

 staled that, in the year 1S27, the author had proposed this plan to the Ad- 

 miralty. This opinion strengthens the vim 1 entertain of the practicability 

 of combining in a very simple way the general ventilation of the ship, with 

 due attention to the ventilation of the frame-work. 



The defect at present in airing the frame, where the interstices of timbers 

 arc made use of, arises from the difficulty of obtaining a current or circula- 

 tion, from the inlet for the air being placed between decks, and no outlet 

 being provided. But were it so contrived as to allow at all times a free 

 current of external air by points of ingress and egress, the effect would be 

 very different. It seems often overlooked, but there is no point more impor- 

 tant to be attended to in spontaneous ventilation, than that where openings 

 are provided for the escape of impure air, others must also be provided foi 

 the supply of fresli air, and vice versa. It must not be forgotten that air, 

 like other fluids, can only fill a given space, or, as one of the earliest writers 

 remarks, '• that unless openings are properly adapted to suffer air to pass 

 freely through, the external air proves a stopper to the internal, and only 

 mixes with the next in contact." The same law which regulates the effect of 

 currents in natural caverns, and which has been successfully applied to the 

 ventilation of mines, will apply with equal force here. We know that the 

 air in a well remains stagnant and pent up ; but as has been remarked, 2 if 

 two wells or shafts are sunk at a given distance from each other, and a 

 horizontal passage cut from the botiom of one well to the other, so soon as 

 the communication is made, there will be a tendency in the air to descend 

 one shaft and ascend the other, whenever the temperature of the external 

 air varied from that below. Applying the principle to the general ventila- 

 tion of ships, there is nothing to prevent the converting of the open spaces 

 between the timbers or ribs, into fresh or foul air flues or conduits. One se- 

 ries of these being arranged to convey down pure air— not to be taken from 

 below, but from above the upper deck— to points of discharge at the floors 

 of the gun and orlop decks, cabin-floors, or wherever requisite, and another" 

 series of openings entirely separated from the first, to commence at the beams 

 or ceilings of these respective places, and pass upward above decks as high 

 as convenient, for the escape of the foul or vitiated air. The points of in- 



1 Captain Symmonds, Surveyor-General of Dock Yards, has, in a man of 

 war now ready for launching at Woolwich, carried the timbers solid about 

 as high as the lower gun purls. Mr. Lang, who is naval architect for the 

 ;„"!i ' i V; 12 °S u "S.now building, I am informed, does not intend carrying 

 up the solid frame nearly so high. ' ° 



2 Letter of John Buddie, Northumberland, 1815. 



gress or egress for the air between decks may be in the form of a horizonta i 

 slit covered with perforated sheet copper or zinc, to break the force of the 

 current. The points of inlet and outlet for the air above deck might have 

 their effect increased, by having the orifices so arranged, that, while pro- 

 tected from the weather, the former would open to, the latter from, the wind. 

 A portion of the interstices of the timbers similarly arranged, communi- 

 cating directly with the open air, could be made to circulate fresh air for the 

 timbers of the ship : but the apertures for the ventilation requisite for crews 

 and passengers, must have no communication with the former, so as to pre- 

 vent the corrupt gases from the bilge entering the latter. Inconveniences 

 may be experienced practically in having the air openings, as described, 

 from the difficulty of constructing those on the upper-deck so as to keep out 

 the water ; but were the principle adopted and carried into practice, the 

 skill and ingenuity of ship-builders would soon overcome any such slight 

 obstacles. Ventilation cannot be attained unless fresh air is admitted from 

 above. 3 When air is made to enter the openings between the timbers below 

 the hatches, as is now done, it must be useless when the latter are put on, as 

 must be obvious to the most cursory observer. Admit, however, the external 

 air, as proposed, and whether hatches were secured down, or side-ports closed, 

 in whatever state of weather, there would be pure air conveyed to the in- 

 mates below ; and although in some cases this mode of ventilation might be 

 imperfect, yet it possesses the advantage of being always in operation, re- 

 quiring neither attention nor labour, nor incurring expense. To make it 

 more complete in winter, the external air openings would require to be pro- 

 vided with means for regulation. 



Were it necessary to attain a greater certainty of perfect ventilation, at 

 all times and in all climates, recourse .may then be had for increasing the 

 circulation to the plan I have alluded to, of artificial suction by heat ; and 

 instead of allowing the foul air to escape upwards from the tubes or pipes, 

 the air might be collected from these into one horizontal trunk, and con- 

 veyed in the galley. 



In iron-built ships, and in all vessels w here there are no interstices between 

 the timbers or ribs, or where these cannot be made use of, iron, copper, lead, 

 i r zinc pipes may be substituted instead. Nor would the space these occupy 

 form any obstruction or ground of objection, as the air-pipes could be made 

 flat or square, keeping the line of the inner wall of the ship. By some such 

 simple arrangements as these, I can hardly doubt very considerable improve- 

 ments would be effected generally in the ventilation of ships, and the ob- 

 stacles to the permanent use of any machine, however perfect, in sailing 

 vessels, must make the view I here take of it more important. It can, how- 

 ever, only be brought about by ship-owners and others giving encourage- 

 ment to the combination or incorporation of ventilating arrangements with 

 the construction of ships, such as have in a similar way been successfully 

 done in domestic and public buildings. (See observations by me on this 

 subject, Arch. Mag., July 1837J 



I do not wish, however, to be understood as inferring that even any such 

 mode of spontaneous ventilation as could be incorporated with the frame- 

 work of ships would prove at all limes sufficient for the ventilation of an 

 wded vessel. The immense deterioration of atmospheric air, by 600 

 to 800 persons crowded inlo a small space, where the cubical contents bear 

 no proportion to the cubic feet of air required for each person (10 cubic feet 

 being considered as requisite per minute to afford a wholesome atmosphere), 

 renders such arrangement next to hopeless without mechanical agency. So 

 long as vessels are overcrowded, hardly any plan can be devised which can 

 afford an adequate supply of fresh air to lower-decks during night ; all that 

 can be done, without artificial means, is to prevent positive injury to health, 

 by affording a constant and uniform supply of fresh air below decks at all 

 times, which surely is deserving of the most serious consideration. 



In very crowded ships, such as troop-ships and others, whether any ar- 

 rangements, such as alluded to, are provided or not, the wind-fan, as im- 

 proved, could be advantageously made use of. Two or more of these ma- 

 chines, worked by hand, would speedily renovate the air of a lower deck, by 

 means of flexible pipes communicating with different parts of the vessel ; in 

 emigrant ships, the passengers would, doubtless, very gladly work these ma- 

 chines for the sake of fresh air in warm latitudes. 



Another ventilator could likewise be advantageously applied in many 

 cases in sailing ships, namely, an exhausting pump, with a hose or pipe, on 

 the principle of pumping out the foul air, or a condensing or force-pump to 

 throw in atmospheric air, worked like the pump of a ship or fire-engine. 

 One of the earliest recommendations of a pump for ventilaiing purposes 

 noticed, is by Dr. Desagulier. He mentions in his experimental Phil., that 

 in the year 1727, he brought before ithe Royal Society an attempt to show 

 how damps or foul air may be drawn out of every sort of mine by an engine 



8 The advantage of conveying air directly downwards fiom the upper 

 deck, has been recently fully established in the Apollo Troop Ship fr 01 

 China, (and one or two other instances,) whose merely small openings at the 

 gunwales, with lids to shut down in wet weather, are made use of. How 

 easily might this principle be extended, and rendered most efficient, as above 

 described ! 



