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February, 1914 exhausting into a low pressure tur- bine, geared to a propeller shaft was to get the highest efficiency on the turbine. propeller. Mr. Emmet talks about putting all the reciprocating engine builders down and out. All I have to say is this, that the reciprocating engine has not been, and I do not think will be for a great while perfected--they have been making improvements on it all the time. For a time the re- ciprocating engine was at a standstill as far as any improvements were con- cerned, except outside details, such as crank pin brasses, main bearings, cross head brasses, but designs and details like that have been improved. The internal parts of the engine, the cylinders and other parts, have not been improved. As late as 1905, about the time that the armored cruisers, the Washington and commissioned, according to Capt. Dyson's paper read yesterday, they had a clearance in the high pressure cylinder of something like 28 per cent. In 1906, I believe, the new gunboat Marietta was finished, and her clear- ances in high pressure cylinder were a little over half, namely, about 15 or 16 per cent. Certainly, that is an aw- ful waste of steam to have such large clearances, and it can be readily seen from the advances' which have been made in reciprocating engines over the Washington and Tennessee class, and later than that, the Connecticut. Certainly our coal consumption per horsepower was very much less on the Connecticut, and one of the rea- sons given by eminent engineering officers was on account of the cutting down of clearances, taking out valve stems and putting in straight brasses, so that the steam could be lifted in a straight passage from the piston valve direct into 'the cylinders in- stead of going through a_ crooked course, and there have been other similar refinements which have in- creased the economy of the recipro- 'cating engines to a very great degree. Montana, were The Delaware The Delaware came along, and that proved to be of about the same, econ- omy as the Michigan and South Car- olina, although Lieut. Commander Dinger believed that the Michigan and South Carolina are slightly better, economically, than the Delaware. The same commander estimates that in the combined system the water rate can be cut down to 8.5 lbs. per horse- power per hour. He takes as a basis all ships actually built. In the Dela- ware the steam pressure carried was about the same as the steam pressure THE MARINE REVIEW in the low pressure turbines of the Utah, and taking the water rate of the Delaware engines for the high pressure cylinders, and also the water for the low pressure turbine of the Florida, and combining the two, he gets an economy of about 8.5 lbs. of water per horsepower per hour, and that is about as good as can be ex- pected under present practice. He also states that he thinks still further improvements can be made, 'and per- sonally I do not think the reciprocat- ing engine has been developed to its full state. I think we have still fur- ther improvements coming, although the trouble is that many engineers have been willing to put in an engine into a ship that is built today--instead of getting up a new design, they will copy an engine which was built seven or eight or ten years ago. crooked, long ports, large clearances and other wasteful features, and if the same at- tention had been given to recipro- cating engines as has been given to turbines lately, I think the reciprocat- ing engine would be in a much better condition today. Conservatism of Engineers R. H. Robinson:--As an engineer- officer in the navy, I want to say that we subscribe heartily to what Mr. Emmet says... There is not one of us who will ever know as much about the Jupiter as: he does. =). do « not think that there is any use of our making that contention. He 'says that it is not a case of our not want- ing the advantages that he gives, but our principal duty is to get things done for us. He says he does not quite understand--I do not think he put it that way exactly--the extreme conservatism of the marine engineer. And I will point out that they have not electrical turbines on locomotives as yet. There is one paragraph in his article as printed that seems to me to indicate somewhat the difficulties that we do not know anything about, and that we must know before we can subscribe heartily to Mr. Emmet's opinion as stated in the article, and the certainty that his scheme is al- ways going to be better than any- thing else. For instance, this collier is sometimes going to have 10,000 tons of coal in it and sometimes not any. What will be the' effect of that on your electrical density? What effect will that have on the operation of the motors? Suppose the -- governor, which is a wonderful governor, and which is completely automatic, does not always function? Suppose it hap- pens to work like the automatic water level regulator on the Belleville? Sup- 35 pose you have a ship pitching heay- ily, will that affect your motors at all? We would like to invite the at- tention of the author, who has done so much for us, to the fact that the Jupiter is a naval collier, and I do not think there are any other vessels equipped with this plan of propul- sion. Question of Reversing W. L. R. Emmet:--Mr. Linnard put the question about reversibility. I saw the ship reverse. She was going about three-quarters speed, possibly, the switch was simply thrown, there was. no experiment made on _ that score. I do not think there would be any stress, except what might come on the propeller blades, and the con- ditions are not essentially different from those of any other ship in that respect. At least, I can see no rea- sons for there being any difference. The question of the relative ef- ficiency of turbines and engines is one that we do not want to discuss here at very much length, because it has been so much talked about, but there are certain underlying reasons why a turbine should be more ef- ficient, because they can provide for the full expansion of the steam and full available energy in the low pres- sure ranges, whereas no steam engine can dO" -that, By going" "from non- condensing to. condensing on steam engines the gain is something like 30 per cent, and going from non-con- densing to condensing on turbines, the gain is more than 100 per cent. There is every reason why the steam engine is necessarily inefficient at low pressure ranges, that is one reason why the turbines have been intro- duced, and why certain refinements will improve reciprocating engines. The history of the art would seem to indicate that the reciprocating en- gine for all purposes to which tur- bines are now introduced has been. universally given up. What I said about knowledge of the Jupiter was not intended as a re- flection on the navy at all, but sim- ply intended to imply that there is no possibility of studying that unit on board ship as it was studied in Schenectady, because we made par- ticularly careful and analytical study of it, in which case we could vary the speed and ldéad, and trace curves of all possible variations, speed with every kind of fixed load, and with fixed speed for pressure, superheat and other conditions. It was the first turbine of the type which we pro- duced, and the reason we built the turbine was this--we first built one of