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316 attempt to adapt the gas engine was- reluctantly abandoned, and the experi- ence of other investigators in this field goes to show that this was an escape from an adventure full of trouble. One thing, however, the writers' in- vestigation did indicate, and that was that no internal-combustion engine then extant could be coupled direct to a lake type of propeller, and that to substitute a suitable type of propeller for the proposed engine, regardless of local requirements in Canadian waters, was to court certain failure under the conditions indicated above. Mechanical reducing gears, though considered, did not offer any great prospect of suc- cess, because the reversing gear on the main engines had to be retained, which certainly promised another source of weakness and loss in canalling, possi- bly a failure to start or to stop under conditions as regards locks and gates certain to result sooner or later in serious disaster. At this time elec- tricity seemed to offer possibly the best prospect of successful solution to this problem. Being satisfied that the single lake type of propeller and the facilities for maneuvering the same un- der steam would have to be retained if failure was to be avoided, it re- mained to find some third feature through which the desired large, slow turning propeller could be reconciled with the comparatively light high speed internal combustion engine of the Diesel or other type. It must be admitted that the introduction of elec- tricity for this purpose, while commit- ting one to a certain loss in trans- mission, gave assurance of certain in- cidental advantages of great value which had not originally been antici- pated. Simplicity of Reciprocal Engine No internal combustion engine, Die- sel or other, known to the writers, is an absolute substitute so far as sim- plicity of operation and reliability of handling are concerned for the ordi- nary up-to-date triple expansion steam engine, even in deep sea_ go-head work, much less in maneuvering in matrow waters within harbor limits or in rivers or canals. Whatever suc- cess may have been obtained by the recently developed two-cycle, slow speed, marine type of Diesel engine-- and there is here no suggestion that success has been other than most en- couraging--it still seems that the line of development followed is not such as appears likely to lead to the evolu- tion of a propelling engine, which an owner will be as ready to have in his vessel as he would an ordinary steam outfit. Attention has been paid to obtaining a specious resemblance to THE MARINE REVIEW the marine steam engine in an effort to make the Diesel engine exactly suited to take the steam engine's place direct on the propeller shaft for the sake of a simplicity which is more apparent than real. To get the low revolutions most desirable for propul- sion in slow speed cargo vessels, im- portant advantages in the normal Diesel engine, such as high speed, low weight, and moderate over all dimen- sions, have been sacrificed, while the necessity for fitting reversing gear on the engine itself has added a most 'unfortunate complication, necessitating the lavish use of compressed air in maneuvering, an addition of a par- ticularly troublesome and expensive nature. Furthermore, experience has already shown that the use of large single screw Diesel engines in propul- Fég .19. ACCOMMODATION DESIGN FOR OREOGER WITH ELECTRIC PROPULSION September, 1913 with inevitable trouble. It must be considered also that no engine of the Diesel type, with its numerous spring- loaded, cam-driven valves and other fine-set gear, can take kindly to the vibration set up by the action of a vessel in a seaway. The reference here is particularly to a vessel engined astern, but the same is true of any position of the machinery in direct drive. Finally, any adjustments neces- sary on the Diesel engine, need for which may not be at once apparent-- in fact, which may not become ap- parent at all until serious trouble has developed--must be at once attended to, to avoid trouble, whereas in a steam engine they may without serious detriment be put off to a suitable op- portunity. Enough has been said to indicate CONDENSER: FEQ £ WAT BUNKER SET z om -- \ MOTOR & . \ [PROPELLING PUMP Mor | zo : BOILER ae MAIN CIRC. PUMPS} | zs Oe aston we onus eae! see or ora epg: Si! DREDGE ees ee SES Re ipe c a ARM {----<$§----==== GENERATING SET | BOILER MOTOR PROPELLING MOTOR rhea | PRESSURE WATER _PUAPS SERS. y ~ Bee w gia epee eee (9507.6 ' BUNKER sion is attended with grave risk of the breakdown of the whole propelling mechanism of the vessel. It is idle to deny that there is in- herent in the very operating principle of the Diesel engine an element of delicacy and unreliability very little in keeping with the rough work of ma- rine propulsion, from which the mod- ern steam engine emerges with credit. The fuel economy which has been the one real outstanding claim for the adoption of the Diesel engine is, in fact, dependent on an operation of great nicety, involving the use and maintenance of very delicate mechan- ism. A governor action controlling this mechanism is set in motion by the racing of the engine in a seaway, and the cycle of the cylinder operations, so far from continuing uniform, as is essential for good working, are period- ically interfered with, probably under iinpulses given too early or too late, some of the points which experience has already developed as_ requiring consideration in the present Diesel type of marine engines before its re- liability can be confidently placed in the same category with that of the triple expansion steam engine. After all it is the average ship owner's wish to have a ship which, while attaining all reasonable efficiency and economy in its operations, shall be, first and foremost, trustworthy, and the propul- sion of which will be carried on as surely as the limitations of the best engineering mechanism will permit. It is hopeless to introduce new meth- ods of marine propulsion which do not guarantee all the security and cer- tainty of the mechanism which they displace. Therefore it suggested that it is unfortunate that so much effort has been devoted to attempting to force the Diesel engine into con- ditions of service for which it appears is