1842.] 



THE CIVIL ENGINEER AND ARCHITECTS JOURNAL. 



II 



planks without timbers; this method hns not been extensively used. 

 Clinker-built boats belong to this third system, and perhaps also iron 

 vessels, inasmuch as the plates of iron of which they are formed are of 

 far more importance than the iron ribs, which occupy the position of 

 timbers. 



The advocates of iron have, I apprehend, by no means esaggerated 

 the defects of ships of the common construction, in which the con- 

 nexion of the timbers with each other is extremely imperfect, even in 

 the best built merchant ships, and the safety of the largest vessels is 

 depeudeut on the security of the fastenings of the butts of a l-inch 

 plank. 



I consider these defects are so fatal that no increase of strength or 

 improvement in workmanship can more than palliate them in agreater 

 or less degree, and I propose to abandon any reference to these vessels, 

 and at once admit their inferiority to vessels constructed of iron, pro- 

 vided the latter are made of sulCcicnt strength. 



A large proportion however of the present enormous annual loss of 

 merchant ships seems to have been sulliciently traced to defective 

 methods of construction, and tu the facility il allbrds in covering the 

 defects of cheap ships; still the causes that tend to foster the con- 

 tinuance of the present system are subjects foreign to the tenor of 

 tliese remarks; the fact that the rottenness of the timbers can be con- 

 cealed from casual inspection, is sullicient for our purposes. It has 

 been urged that unless spaces are provided between the timbers, for 

 the accommodation of water from leaks, that it would rise in the vessel 

 and spoil the cargo. This argument is founded on the assumed ne- 

 cessity of leaks, but it affords proof of their frequent occurrence in 

 vessels of the usual construction. 



The rapid destruction of timber by the united operations of wet, 

 heat and liltli, and the generation of foul air from these causes will not 

 be denied ; and in addition to its weakness the rapid deterioration of 

 the frame of the vessel, from the above causes, seems an equally fatal 

 objection — though exceptions may occur owing either to care or 

 accidental conditions. 



The second system of ship building with timbers wedged up solid, 

 has been in use for a considerable period for ships of war, and the i 

 success that has attended this plan has been amply proved by the ac- 

 counts of the escape of ditfercnt vessels, that have since its adoption 

 been driven ashore and got olf igain, in many instances without injury, 

 and in other cases damaged to such an extent as wouM have insured I 

 the total loss of vessels of the common construction ; fur instance, the I 

 Pique lost a large portion of her keel, and in some places the whole 

 of the g-arboard strake, and a part of the floor timbers weie ground 

 away by the rocks of Newfoundland, and yet this frigate crossed the 

 Atlantic without a rudder, under circumstances, it must be admitted, 

 of some anxiety to the oflicers and crew. 



For merchant ships I should propose to use the same weight of ma- 

 terials as are now employed, tiie outside planking would remain with- 

 out alteration, but the quantity of wood iu the ceiling would be added 

 to the width of the timbers, and in case it was insuHicient to till up 

 the spaces between the timbers, the depth of the latter must be lessened 

 to make up the deficiency. 



Under these circumstances the timbers would be about double the 

 thickness of the outside planks, and being placed close together, a 

 good means of connexion might be obtained by large dowells or coaks^ 

 so as to produce a mutual dependance on each other, and so that any 

 pressure on the outside would exert a more regular strain on every part. 

 A ve>sel constructed on this principle would be ai^ irregular cask, anii 

 when caulked inside and outside would Hoat without planking ; and by 

 the addition of the latter, a frame of great stiHness, and equal strength 

 and thickne-is in every part would be obtained, on which one side of 

 every piece of ^vood u»ed in its construction would be visible, and 

 would allow an examination to be made of its state with great facility. 

 The other sides of the wood would be preserved from wet as long ns the 

 fabric of the vessel remained sound, anil the caulking was attended 

 to. It is obvious that a greater inside width of ' or 8 inches would 

 be gained in these ves-ieU, and no loss of space would accrue if it was 

 occupied by battens to admit of water accommodation for the leakage, 



and the prevention of injury to the cargo from the escape, until at 

 least the present advocates of the assumed necessity of leaks in ships, 

 became convinced of the small prospect of their occurrence under 

 common circumstances in vessels so constructed. 



It is true no provision will afford security to vessels on rocks among 

 breakers, but such situations atTord the best test of the merits of dif- 

 ferent systems of ship building, by the time each vessel is found capa- 

 ble of resisting these effects. 



Numerous c;ises will occur where life is dependent on the time the 

 vessel holils tigether, but the partial saving of the cargo may be con- 

 sidered objectionable by ship owners, among whom the advantages of 

 a total loss are well understood. Opinions on these points are of 

 little value, we must wait fur evidence froiu wrecks under different 

 conditions. 



The scantling proposed for merchant ships would, I apprehend, be 

 not quite so heavy as that in use for ships of war of equal site ; at the 

 same time, it is probable that the strength of timbers placed close to- 

 gether, except thatof the dockyard plan of timbers wedged up, to such 

 an extent that a greater strength may be perhaps obtained ut a smaller 

 cost. Plans of this nature are obviously only suited for good workman- 

 ship and good materials; but it ought to suit, for less iasnrance pre- 

 miums, whenever an inquiry on this subject is properly conducted, and 

 explanations are afforded to insurers of such a nature, as shall be fully 

 understood. 



The third plan referred to, requires similar conditions of timber 

 and workmanship, but it has not been extensively adopted. Ten or 

 twelve series of inch planks were employed many years ago, in a 500 

 ton vessel built at Rochester, but I conceive three or four series of 

 2.J to four inch plank, according to the size of the vessel, would be 

 found a more convenient method of construction. 



Several of the Gravesend st'eamers of 150 feet in length have been 

 built of three series of Id inch planks, and they have run for 4 or 5 

 years, and are now said to be as sound as wdien first constructed, such 

 at least was the case with the Ruby, when opened for the purpose of 

 lengthening the bow to increase her speed. 



This method however requires farther trial, especially at sea, before 

 anv decisive opinion can be given on its comparative merit : it is fa- 

 vourable to soundness, as the necessity of sawing the wood into 

 plauks admits of the certain selection of good materials, and would 

 afford great facility in seasoning timber properly. While the expense 

 of selection would in some degree be lessened by the conversion of 

 the rejected planks to inferior purposes, or by working it up in inferior 

 or cheap craft, perhaps for river use. The increase of cost would not 

 answer unless it was accompanied by a proportional increase of dura- 

 bility, and perhaps the general opinion would be iu favour of the 

 latter result, as a necessary consequence of the selection of good 

 timber. 



The launches used in the navy have for several years been made on 

 Johns' plan, of two series of planks crossed diagonally, their weight is 

 about ^ of the boats of the old construction, and their durability has 

 been much increased. The Gravesend steamers are built with two 

 similar scries of crossed planks in lieu of timbers, covered with an 

 outside planking in the common mode, the whole well fastened with 

 copper. — in large vessels perhaps a ceiling connected in the snme 

 manner might be deemed advisable: at the same lime it seems pro- 

 bable that a greater strength would be obtained by a less quantity of 

 timber in the third than in the second method of construction proposed. 

 Clinker built nhicli belong to this class, in which the principal strength 

 depends on the planking iastead of the timbt-rs, seldom exceed lOU 

 toiis iu size, and are usually of a slight scantling ; theirgreat durability 

 is well ascertained, provided they are kept from the ground, iu which 

 case from the thinness of the single part of the planking, boles are 

 easily knocked in their bottoms. 



The introduction of these methods of constructing timber ships 

 is not likely to be eilected, except by the nearly total destruction of 

 the present trade in ship building, by the more general ailopliun of 

 iron vessels, and the interests of humanity «ill cause the earliest oc- 

 currence of this result nut to be regretted. Nothing perh«p» *<ut the 



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