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28 circular section which is securely bolted to a keelson near the bows, and supported in an arched position, at about the height of the "Texas," by substantial wooden struts, finally passing over the heavy framing which supports the wheel and terminating in the structune which carries tle shaft bearings. Turnbuckles are provided so that any slack which may occur can be readily taken up and the whole girder kept taut and rigid. It is usual to have the highest point of these girders at the after end where the greatest weight occurs, but oczasion- ally they attain their greatest elevat:on amidships. This plan has been a:iopted in the construction of the Virginia and Queen City of the Pittsburg and Cin- cinnati Packet Co.'s fleet, whose loity "hog chains" form an enormous cir- cular arc with the highest point about abreast the pilot house. The extraordinary flexibility of these wooden hulls is remarkable. They can stand an amount af, racking and twisting without starting a seam, that would have streams of water pouring into a deep sea vessel constructed of the same material. The steamer Virginia before referred to was 071 one occasion nearing Pittsburg when she grounded on the point of a bar. Instead of accomplishing this mis- fortune in the orthodox fashion and striking bow on, she ran afoul of the bar amidships, leaving the ends entirely unsupported. For an instant she hung suspended in this perilous 'position, when suddenly the starboard hog chain snapped with a report like that of a gun. The tremendous and extraordinary stress now imposed on the port chain was resisted for a few moments, but the enormous strain soon parted it also allowing the stern to drop about 18 in. This bending, together with the local disturbance which it caused, permitted the boat to drift off into deeper water. Exam- ination soon disclosed the fact that she was making very little water, but that the hull timbers were under a fearful strain, although the natural elasticity of the material prevented a complete rupture. As quickly as pos- sible all freight and other heavy weights were shifted from the ends to amidship, which relieved her to such an extent that she was able to proceed under a "slow -bell" to her destination in safety. That trip has 'ever since been memorable in river annals. Deprived of the rigid sup- port of her hog chains, the pliable hull responded with sinuous move- ments to every impuse of the paddle- wheel, and set bulkheads, partitions THe Marine REVIEW and decks, groaning and cracking like an. old house in a storm. When she was finally hauled out on the marine ways it was found that. she had sus- tained no serious damage at all. Her stern was jacked up to its proper position; new chains were fitted and she is in service today performing her usual duties as well as before the ac- cident. This experience was somewhat unusual, but the rough handling and frequent groundings to which these boats are subject, continually tends to produce a more or less serious deformation of the hull. Occasion- ally they get an unusually severe bump and then the deformation be- comes permanent and manifests, itself by a broken and irregular sheer line. Side-wheel steamers have all their machinery located amidships so that no special precautions are taken to provide longitudinal strength, beyond disposing the material in the hull so as to be capable of resisting all prob- able stresses, both longitudinal, which are the most severe, and transverse, which are also quite important on ac- count of the weight and impact on the water of the heavy wheels. All steamboats are provided with, overhanging guards, primarily to in- crease the deck space as much as pos-* sible, but they are useful also in pre- venting damage to the hull in case of a collision. These guards are not fitted with spondels or _ sustaining brackets of any sort, as they would be damaged or carried away by float- ing drift, but are supported by run- ning the wooden main deck beams out to the heavy fender. The exten- sion of the guards in side-wheel boats is frequently too great to permit of providing sufficient strength in this way; so additional support is fur--- nished by a system of iron rod truss- es under the boiler deck, with their outer extremities attached tothe fend- er. On account of the extreme _dfaught to which these boats are of- ten loaded, the transverse line of the guards does not follow the main deck camber, but is inclined upward from the line of the hull outward to the fender. If this were done the guards would be constantly trailing in the water whenever a heavy cargo was carried. The construction of steel hulls on the inland rivers has not been: suf- ficiently extensive to result in any well established practice in regard to structural arrangement and sizes of scantlings. However, the tendency seems to be toward very light con- struction and so far the methods of disposing the material are more in accordance with the practice of the structural iron worker than of the ship builder. With the constantly de. creasing supply. of suitable timber and the adaptability of steel to the pur- pose, without an excessive increase in cost, it does not seem as_ though wooden construction, at least for pas- senger boats and towboats of the first class, could long survive. But if the raft-like hull bears so little resemblance to the usual form of floating structures, the propelling machinery is no less dissimilar to the ordinary mechanical devices for the propulsion of ships. There is not that elaborate installation of boilers, engines, and auxiliaries which marine engineers usually consider necessary to a complete and efficient machinery equipment. As with the steamboat itself, so withits propelling apparatus, everything is made subservient to - simplicity, and adaptability to condi- ditions wh'ch are far from being ideal. This finds particular exemplification in the type of boiler which has been almost universally adopted. Many circumstances have contributed tow- ard determining its many peculiar fea- tures. There is no available source from which the boiler feed water may be obtained, except from the river itself, which even in its. most clarified state holds large quantities of earthy and vegetable matter in suspension. The introduction of such muddy _ water into the ordinary type of internally fired boilers, and its conversion into steam, would result in such a loss of heat efficiency as to render their use undesirable. Hence the externally fired large flue boilers, of exception- ally ample graté surface in proportion to heating surface, has been devised; which permits using the raw, unfil- tered river water, without entailing a wasteful expenditure of fuel. It is true that this type. is not especially economical in its use of fuel; but then one cannot expect any very great economy where the bottom blow-out is being constantly used to remove the accumulation of solid mat- ter, which results from the evapora- tion of the water, and when half of the heat energy is unable to pass through the deposit of non-conducting material which continually forms om the flues and interion. of the boiler shell, and which appears to resist the efforts of all boiler compounds t0 eradicate. However, they possess 4 fair amount of steaming ability, and on account of the comparatively small amount of. water which they contain, respond with . considerable .