1840.] 



THE CIVIL ENGINEER AND ARCHITECTS JOURNAL. 



277 



Treatise on the Theory and Practice of Xa ra I Architecture. By Augus- 



TIN B. Crewze, Member of the late School of Naval Architecture, 



&c. Edinburgh: Black. 1S40. 



This is a reprint of the article Ship Building, from the Encyclopedia 

 Britannica, and a work well calculated both from that circumstance 

 and its own intrinsic merits to become a popular treatise. Such a 

 form necessarily restricted the author within certain limits, and forced 

 on him the option of neglecting either the theory of liis subject, or the 

 constructive portion, and as the latter has been the subject of numerous 

 works, it is less perhaps to be regretted that Mr. Crewze should have 

 chosen to elucidate the general principles of the art, with which he is 

 so fully conversant. Tlie theoretical portion derived from the best 

 authorities, foreign and native, and illustrated from original sources, is 

 perhaps one of the best works to which the student can be referred. 

 The practical part good as far as it goes, is confined in itself, and in 

 the view it takes of the subject, very little being said of steam navi- 

 gation, and no general account of iron ship-building, steam ship-build- 

 ing, &c. This is to be regretted, for these departments are certainly 

 neither of themselves, nor considered with regard to the future, as the 

 least important branches of naval architecture. 



The history of ship-building is sound and good, and is as useful as 

 it is interesting, we cannot however make any extracts from it. The 

 author's observations on the present state of his art, we are also ob- 

 liged to dismiss thus cursorily, although the subject is one impera- 

 tively requiring pnltlic attention, and to which the notice of our 

 readers should be directed. This work will doubtless go a great way 

 towards dispelling the ignorance and prejudice which exist on this 

 subject, and towards a reform so much demanded in the scientific de- 

 partment of the dockyards. We think with Jlr. Crewze that the ton- 

 nage laws and legislative restrictions are the true root of the evil, for 

 otherwise we feel convinced, and we think the history of the art shows 

 it, that our countrymen are not so far deficient but what, as in every 

 other case, they would have distanced their competitors. We are 

 favourable to a restoration of the Naval College, but then it must be 

 an open institution, not a jobbery for a score of cadets, but an estab- 

 lishment where the merchant ship-builder and the artisan may obtain 

 instruction on fair terms. As Mr. Crewze has well demonstrated, no- 

 thing has been gained by exelusiveness, and nothing will be gained, 

 so that the sooner the last traces of " the mysterie of sliippe buildinge " 

 are got rid of the better. The character of the pu]iils of the late in- 

 stitution Mr. Crewze has best defended by the proofs he has given in 

 this work of their capacity and attainments; their contributions to the 

 Papers on Naval Architecture, and to the present treatise, would do 

 honour to any profession. 



Although this is an elementary treatise, it contains so much valuable 

 matter that we should, if our space permitted, make copious extracts 

 from it ; most of the tables for instance are very valuable. Perhaps 

 one of the best specimens will be the following comparison of the 

 technical differences between Frencli and English ship-building, de- 

 rived from Mr. Crewze's own observations, we are obliged liowever 

 to omit the illustrations. 



We shall now proceed to notice some of the peculiarities observable in tlie 

 Prench practice of sliip-building. The characteristic difference in tlieir sys- 

 tem from our own, wliicli wouki strike an observer accustomed to English 

 ship-building, would evidently be a less expenditure of material. 



The French have retained tlie old system of frames aad filling: timbers. 

 Frequently the frames are close jointed throughout tlieir height, and the fill- 

 ing frames put up as single timbers. The filling timbers are also fretpiently 

 of fir. Both frames and filling timbers are chain-ljolted. Tliere is no slielf 

 under the beams, only a thick clamp, and a wide chock worked u])on the short 

 stuff, and up to the beam. There are generally three side binding sfrakes 

 faced one inch on, and scored one inch over the beams, and Ijolted together 

 by in and out bolts passing through the water-way, which is also faced and 

 scored in tlie same manner. These bolts are secured with nuts and screws at 

 the points, on the outside plank. 



The water-way is not always scored over the beams, but is sometimes 

 brought plain on their ends. The bolts of the binding strakes, which are tlien 

 also merely brought on to the beams, secure its lower edge ; and in both 

 cases it has in and out bolts through tlie ship's side, to secure its upper edge. 

 The method of connecting the beam-ends with the ship's side, which ap- 

 pears to be most generally adopted in the French sliips at present, consists of 

 a chock under the beam, securely bolted througli tlie sliip's side, the points 

 of the bolts being set up with a nut and screw. The beam-end hooks over 

 the head of this chock. A plate-knee similar in shape to that known in the 

 English service as Roljerts' knee is brought on each side against the chock 

 and beam ; but these knees, instead of ha%'ing a short arm against the ship's 

 side for taking in and out fastenings, themselves form the bolt, each knee 

 having an arm which is driven through the side by means of a shoulder 

 worked in the knee, similar to tlie slioulde-r of a dog-bolt. The outer end is 

 secured by a nut and screw. The security of the plate-knees to the beam and 



chock consists only of three screws in each arm, and one screw in the diago- 

 nal brace. These screws are not above five inches long. Thns the security 

 of either knee is completely unconnected with that on the opposite side of 

 the beam. 



The wales, diminisliing stuff', and plank of the bottom, are all treenail-fas- 

 tened, the huts are secured with two bolt-nails in the timber on which the 

 but is placed, and a through-liolt is driven in the timljcr next the but. In 

 some instances the plank is nail-fastened, but wdiether with nails or treenails 

 it is double fastened. The treenails are not caulked on the ceiling, but 

 wedged with conical wedges, ilost of the principal bolts, as those of the 

 water-ways and chocks, under the beams, are set up outside with a nut and 

 screw ; and great care is taken to omit the fastening of the wales and outside 

 planking, wherever these bolts can he advantageously made to answer as fas- 

 tenings for them. 



There is no regular system observed in shifting the bnts of the plank, as 

 there is in the English service ; but the planks are worked to their full length, 

 without reference to the sWt : the only rule which appears to be observed 

 is, that there shall be about two feet shift between the Inits of following 

 strakes. 



Katlier an interesting experiment as to the possibUity of diminishing the 

 scantling of the timber, to any great extent, which is used for building large 

 ships, is in progress in the French \\a\y. The Surveillaiite, a large frigate, 

 was built wholly of small timber, about ten years ago, and as yet the reports 

 on the system are favourable. 



The following is an outline of the jilan on which she was built. 



The keel, stem, and stern-post are formed of various pieces of timlier com- 

 bined. 



The several lengths of the centre piece, or core, are scarphed together, 

 while the side or strengtliening pieces only but with plain huts ; care being 

 taken that the Ijiits and scarplis give good shift to each otlier. 



There are in this system no other frames than those which form the sides 

 of ports, and the timbers composing these frames are bolted together, with- 

 out leaving any opening between them, that is, close jointed. The spaces 

 between the frames are filled in with single timbers, or rather with a frame 

 work of timber fitted together. 



The cant-bodics are framed as in the ordinary method, the after-body tim- 

 bered round to the post witliout transoms or fashion-pieces. 



From the main-deck ujiwards the scantlings of the frames are not different 

 from those of a ship of a similar size Iniilt in the usual manner ; but below 

 this line tliere is a very considerable reduction. This reduction commences 

 at the lower edge of the gun-deck clamps, and there a couple of thick strakes 

 are worked up to the lower edge of these gun-deck clamps, to form an abut- 

 ment for a series of internal timbers, brought on the inner surface of the 

 timbers of tlie frame, and crossing them at an angle of 45°, the upper ends 

 being placed forward in the fore-body, and aft in the after-body. These 

 timbers but at their lieels on the lieads of a series of internal floor-timbers, 

 brought on the upper surfaces of the floors of the frame. These internal 

 floors are laid atliwartships. The openings between the timliers of this in- 

 ternal diagonal frame are filled in with wedge-lillings, so that the whole hold 

 presents one smooth surface for stowage. 



Wherever there is an athwartship bidk-head, there is a system of riders 

 worked on the inner surface of this diagonal frame, but taking a vertical 

 direction. Tlie timbers of these bends of riders are not wrouglit side by side, 

 but one series of timbers is worked on the inner surface of the otlier, and the 

 bolts pass in and out through both, and through the bottom. These riders 

 run up to tlie lower deck, and a beam is so disposed with respect to each 

 bend of riders, as to be secured to their heads, and form a part of the system. 

 The bulk-heads which necessarily fill in the space between the beam and the 

 riders run diagonally uj) on either side the middle from a midship pillar to 

 the beam and riders. Each bulk-head is water-tight. 



It is lamentably true, we fear, that the French are superior to us in 

 many departments of naval architecture, and it is therefore incumbent 

 on all classes interested in the national prosperity to exert tliemselves 

 to remove the legislative obstacles, which interfere with our progress, 

 seriously injure us at present, and menace ruin for the future. Eng- 

 lishmen only want to be allowed to go in the right way, and not to be 

 forced into the wrong way. 



GiLDixG OF Metals by Electro-Chemical Action*. — M. de la Rive 

 has succeeded in gdding metals by means of this powerful action. His me- 

 thod is as follows : he pours a solution of chloride of gold, (obtained by dis- 

 solving gold in a mixture of nitric and mmatic acid,) as neutral as possible 

 and very dilute, into a cylindrical bag made of bladder ; he then plunges the 

 bag into a glass vessel containing very slightly acidulated water, the metal to 

 be gilded is immersed in the solution of gold, and communicates by means of 

 metallic wire with a plate of zinc, which is placed in the acidulated water. 

 The process may be varied, if the operator pleases, by placing the acidulated 

 water and zinc in the bag, and the solution of gold with the metal to be gilded 

 on the glass vessel. In the course of about a minute, the metal may be with- 

 drawn, and wiped with a piece of Unen ; when rubbed briskly with the cloth 

 it will be found to be shghtly gilded ; after two or three similar immeisions 

 the gilding will be sufliciently thick to enable the operator to terminate the 

 process. — Athenmun. 



2 P 



