None
In the Navy, in consequence of the high revolutions, it was found better to have independent feed pumps, and, later, to take from the main engine all pumps except the air pump. This practice was soon followed in the mer- cantile marine with fast running engines. Then fresh water for making up the water from the boilers was deemed necessary, and evaporators or distillers were used. Starting and turning engines were known then, but have been used very generally since ; they are now regular fittings in ships of all sizes. Feed-water filters are common where ships are engaged in long voyages and use oil in the cylinders. All these things add to the weight of the machinery without contributing anything directly to the I.H.P. used as divisor. The I.H.P. developed in the auxiliary macliinery of a warship is now enormous, and can be gauged by referring to Table xxxiv. In a large merchant steamer, especially long voyage express ones, the auxiliaries add very much to the weight and steam consumption. Spare Gear also adds to the weight, and is more in extent to-day than was formerly the case in the mercantile marine ; but less in the Navy, where in old days nearly half an engine was carried (v. Appendix C). Fuel. — The consumption of fuel is another most important factor in all considerations of weight ; especially is this the case where, as in the N orth Atlantic, the distance between coaling stations is long. It is no use paring down the weight of the machinery if by so doing the fuel consumed per I.H.P. is increased. The great cry of the opponents of the water- tube boiler is that the increased consumption of fuel outbalances the saving in weight, so that, for a given voyage, the total weight of machinery and fuel together is greater with a water-tube boiler installation than with a cylindrical one with Howden's or Ellis' forced draught. Twenty-five years ago 2-5 lbs. per I.H.P. was the general rate of consumption of good coal; a little later it was as low as 2 lbs. with the very large three-crank com- pound engines. The triple engine in its early days consumed 1'7 in a general way, and 1 -5 under best conditions. Now the best engines with forced draught and hot air, feed heaters, &c., consume 1*25 lbs., and ordinary good triples and quadruples 1*4 to 1-6 lbs. of good mercantile coal. In the Navy the consumption of coal (including auxiliaries) was with triple-compound engines and the cylindrical boiler 1 -8 lbs. of Welsh coal when running full speed. To-day it is from 1-8 to 2-2 lbs. with the water- tube boilers under sea conditions. If the I.H.P. of the auxiliaries were included the rate would, of course, be somewhat lower in both cases. Relation of Weight to Tonnage. — Taking the same period as before, it is interesting to note that in Atlantic mail steamers the machinery was 13 per cent, of the displacement, and the I.H.P. at the rate of Tl per ton of gross register. In small passenger steamers it was about 13 per cent, and 1 "35 per gross register ton. Ten years later the speed of ocean steamers had increased by 20 per cent. The weight of the machinery was still about 13 per cent, of the displacement, but the I.H.P. was 18 per gross register ton. The increase of speed with the smaller steamers was 25 per cent., the CROSS-CHANNEL EXPRESS SERVICE. 519 weight of machinery 15 to 19 per cent, of the displacement, and the I.H.P. 1'5 to 1'7 per gross register ton. In 1895 the Atlantic express steamer had a speed of 21 knots obtained with machinery whose weight was 20 per cent, of the displacement, and whose I.H.P. was at the rate of 1"9 per gross register ton. Twin screw cargo and passenger boats with a speed of 15 knots of this period had a weight of machinery of only 7 "3 per cent, of displacement and less than 1 I.H.P. per gross register ton, while in similar boats of 13 knots speed the proportions were 5 per cent, and 0*5 I.H.P. Fast Channel screw steamers of 17A knots were at the same time on service with machinery weighing 27 per cent, of the displacement, and indicating 3 to 5 H.P. per gross register ton. To-day 23-5 knots is attained by the fastest express Atlantic steamers by means of machinery requiring 23 per cent, of the displacement to carry it, and developing 2-3 I.H.P. per gross register ton. A speed of 25 knots is now aimed at by the Cunard Company to compete with the magnificent German steamers at present taking the lead in the Atlantic. In the Navy a quarter of a century ago a speed of 18-5 knots was attained on trial trip by machinery whose weight was 27 per cent, of the first-class cruiser's displacement. Ten years later the same speed was attained with triple-compound engines only 15*5 per cent, of the displace- ment in weight. To-day 17*7 per cent, is allotted for a speed of 24 knots ; in second-class cruisers 15 per cent., and in third-class cruisers 16 8 per cent, for speeds of 20 to 21 knots. The destroyers' machinery for 30 knots has a weight equal to 46 per cent, of the displacement. The Express Ocean Steamer to-day is of enormous size, even larger than the "Great Eastern," which, until quite recent times, was deemed to have been a huge mistake on account of her size. The speed of the " Great Eastern " was, however, very small compared with that obtained by the magnificent steamers recently placed on the Atlantic service by German enterprise, and which attain at sea an average speed of over 23 knots with a consumption of coal not exceeding 13 lbs. per I.H.P. By referring to fig. 11, it will be seen that the designers of the machinery of the " Kaiser Wilhelm II." have not been unmindful of the weight that was to be saved by careful design of the fixed parts, such as the columns and foundations, and it is no doubt due to this that these engines can develop 7 H.P. per ton of total weight of machinery in spite of the high boiler pressure of 220 lbs. To similar causes may be traced the fact that the French designers of "La Savoie " could obtain 9 H.P. per ton. The Cape, Australian, and the East Service is now generally performed by steamers of somewhat smaller size than those on the Atlantic, and whose trial trip speed is about 18 knots. In Cross-channel Express Services we find some of the most interesting examples of Naval architecture and marine engineering, most of which show that by following on the lines of Naval design, but not going to its full extent, very high speeds are safely and satisfactorily obtained. Messrs. Laird Bros, have shown that even a speed of 23^ knots can be maintained on service with such machinery in a ship of only 2700 tons displacement. To-day this class of steamer is to be found on the North Sea, English Channel, and Irish Channel, doing daily and nightly service at speeds varying from 17 to 20 knots, with displacements ranging from 1250 to 520 MANUAL OF MARINE ENGINEERING. 2500 tons, by having engines indicating 9 to 10 H.P. per ton of total weight of machinery, and whose fuel consumption is only 1^ to If lbs. perl. H.P. For Shallow Water Ports and River Service the paddle engine has con- tinued to hold its own (although twin screws could be used in most instances) by their constructors so designing the engines that 8 to 9 H.P. is now developed per ton of total weight, as against the 6 to 7 H.P. of the light paddle engines of thirty years ago, with a fuel economy that will compare favourably with that of screw engines. The following table gives the conditions now r\;ling which affect the question of weight, as well as the weight of the various engines now in use on shipboard : —  "^ 00 o o CO CI r- o o B 2 PHO CO ^ -* CO a 3 o oo O ^ -, O <M o CO CO CO o oo C-1 CO o p o o p o p p : -f _ro iM o o o ■* T3  CO CO o o •i* o o p •CO •^-g^s 01 o o >o  •o o lO CO o o r- f5& ■M CO ^ C-J T' c< CO CO UO ift ^ Tl< CI -^ o ^ o o O^i in o 00 ■* l^ 00 O iO lO o o lO CO 1?) t-- CI CI CO 03 o CO O '~^ I. c3 '=^.6'^'®" 7^ ^^ T' lO CO C) ^^ o O —  o 03 'i- e3 rt =3 O ;_, ^ Oi C«5 -H CI p_, ^H CI o CO ' O OOl o 0> 05 CO ^ — -^ o o o '.o IC lO to (^ o Tj< oo o •^ o ^ s O O ^ C5 C) IM CI CI CO 1-^ o lO ■* o 00 o o ,—{ o CO OD CO ^Oi "-' _. o oo o o 0» CO ^ lO d o o o ic t- CO CO o CO to a o^ lo^ o CO o CO o ^  o ^ o LO -1 CO  '^ O O '-0 "H ■* o IQ t~- ^ CO 1ft C5 • ^ O C-1 o lO -1 CO o —' r- VD ti "3 a 02 O OOO 00 0 0 03 O J. TABLE L. — Particulars of Naval Ships' Designation. When Built. ij fc ^ ro Kind of Engines. Cylinders. Full Speed. P. •6 2 "Si o t: Diameter. .23 a J3 a o o a o f§i il i Ex 1 '& i Ins. Ins. Ft. Lbs. Battleship, 1870 1 fitorizontal Trunk Surface-Condensing, 2 127 (= 118) 54 71-5 643 20-1 Do., 1870 1 f Do. Return Connecting Rod Surface") \ Condensing, - - - - / 2 120 54 62-7 564 19-5 Do., 1870 1 Do. do. do. do.. 2 98 48 68-4 547 19-6 Do., 1870 2 Do. do. do. do.. 4 72 36 72-2 433 23-0 Do., ISSO 2 Vertical Direct- Acting Compound, - i 60-104 42 82-1 575 22-3 Do., 1885 2 Do. do. do.. 6 77-55-77 48 so-o 640 25-8 Do., 1888 2 Do. do. do., • - 6 45 100-0 750 Dj., 1890 2 Do. do. Triple, - 6 43-62-96 51 950 807 34 '8 Do., 1895 2 Do. do. do., - 6 40-59-88 51 103-0 875 33-1 Do., 1897 2 Do. do. do., - 6 40-59-88 51 103-0 875 38-4 Do., 1899 2 Do. do. do., - 6 30-49-80 51 108-5 922 49-0 Do., 1901 2 Do. do. do., ■ 6 31§-51J-84 51 110-2 936 50-5 Do., 1903 2 Do. do. do., - 8 33J-54f63-63 48 120-0 960 50-2 Cruisers— 1st Class, 1870 1 Horizontal Ti'unk Surface-Condensing, 2 (= 104i) 48 74-1 593 24-0 Do., 1877 2 Do. Return Connecting-Rod Compound, 8 41/75-41/75 36 97-2 553 24-S Do., 1885 2 Do. do. do. do.. 4 46-86 39 95-1 618 26-1 Do., 1888 2 Do. Direct-Acting Triple, - 6 36-51-78 42 116-0 812 37-1 Do., 1890 2 Vertical do. do., - 12 36-52-80 48 105-0 840 41-8 Do., 1894 2 Do. do. do., • 6 40-59-88 51 106-0 900 33-4 Do., 1897 2 Do. do. do., - 8 45-70-76-76 48 113-0 904 51-7 Do., 1899 2 Do. do. do., - 8 34-551-64-64 48 116-6 932 46-7 Do., 1901 2 Do. do. do., - 8 34-55J-64-64 48 118-9 951 50-3 Do., 1902 2 Do. do. do., • 8 36-59-68-68 48 120-0 960 50-6 Do., 19(12 2 Do. do. do., - 8 43^71-814-81^ 48 122-4 979 50-8 Do., 1903 2 Do. do. do., - 8 37-60-69-69 42 140-0 980 49-3 Do., 1903 2 Do. do. do., - 8 43^-69-77-77 42 135-0 935 44-1 TABLE La. —  1886 2 1889 2 1SS9 2 1891 2 1896 2 1898 2 1900 2 1870 1 1875 1 1878 1 1884 1 18S5 2 1887 2 1888 2 1890 2 1890 2 1891 2 1898 2 1901 2 1903 2 Horizontal Trunk Surface-Condensing, Do. Direct- Acting Surface-Condensing, Do Return Connectiug-Rod  / Horizontal Return Connecting-Rod Surface ) \ Condensing, - - - - ) Do. Return Connecting-Rod Compound, Do. do. do. do., Do. do. do.  88 42 74-2 520 20-3 88-72-88 48 70-0 560 24-0 42-80 45 90-0 675 26-7 38-64 39 120-0 780 40-4 34f51-76J 36 140-0 820 41-0 33A-49-74 39 140-0 910 40-0 33^49 74 39 140-0 910 38-8 33-49-74 39 144-2 936 40-3 26-42-68 39 141-0 916 50-9 26-42-48-48 30 181-3 906 492 55 30 90-3 451 20-0 57-90 83 95-8 527 21-1 46-64 36 96-0 576 22-1 42-72 36 80-3 481 26-3 26-46 30 150-0 7.'i0 44-4 27-50 33 150-0 825 33-2 26-37-57 33 150-0 825 36-4 26^39-57 27 220-0 990 30 0 30i-45-68 33 160-0 880 24-0 30i-45-68 33 160-0 880 37-1 20^-33-54 27 218 0 981 52-7 20J-33 -38J-38i 24 250-0 1000 52-0 24|-38J-42i-42i 24 250-0 1000 57-3 NAVAL SHIPS MACHINERY. 523 Machinery (Battleships and 1st Class Cruisers). Full Power 4/5 or Natural Weipht I.U.P. ^ Trial. Draught. of Machinery. Full Speed per a Niiiiiber and Kind. 5 I.H.P. Speed I.H.P. Speed. Total. 2 Si 0 S! §1 "3 g C'/J 5 •1- fi^ o s 01 r,i)R QQ 2^ &: Lbs. Sq.ft. l?of*- Knots. Knots. Tons. Box, .... 300 840 22,200 8,539 14-69 7,187 13-8 1090 286 339 7-83 10-2 38-5 0-126 Do., ... - 31-6 7,842 14-97 7,470 14-7 1043 300 313 7-48 0-1-29 Do., .... 30-0 570 14,388 4,960 13-75 714 327 6-86 8-6 34-0 0-103 Do., .... 31 -V 515 14,115 4,914 14-0 4,311 13-2 750 342 Vi9 6-55 9-5 33-9 0-125 Cylindrical, 65 608 17,500 6,624 14-4 998 337 6-64 10-9 37-9 0-131 Oval and cyliudrical. 90 667 22,784 10,184 16-75 8,000 16-2 1266 278 354 8-04 15-3 44-7 0-151 S.E. cylindrical, 9U V90 20,587 11,271 16-75 8,277 16-0 1209 241 331 9-30 14-2 54-7 0-114 Cylindrical, 13d 629 18,930 12,465 16-75 8,813 16-2 1015 189 25S 12-20 19-7 65-8 0-015 S.E. cylindrical, 155 731 20,348 11,500 17-5 9,430 16-75 1163 224 276 10 00 16-0 56-6 0-082 8 do. do., 155 81V 25,233 12,414 18-0 10,404 170 1341 241 ■?.S2 9-30 15-2 49-3 0 090 Belle'i'ille, 300 1050 33,770 13,763 18-5 10,454 17-2 1290 209 280 10-70 131 40-8 0100 Do., 300 IIVO 37,120 15,503 18-5 11,626 1400 202 270 11-10 13-2 41-8 0-093 Mixed, 1390 43,260 18,220 19-0 13,670 15S0 196 260 11-40 13-1 42-1 0113 Box, .... 30 900 24,868 7,361 16-5 1043 317 7-06 8-18 ?9-fi 0-lSO S.E. oval, ■ 65 690 19,500 7,714 18-5 6,658 170 1012 294 340 7-62 11-18 39-5 0-271 8 S.E. cylindrical, - 90 546 15,160 5,661 16-6 776 .307 7-29 10-37 37-2 0-180 4 D.B. cylindrical, - 130 492 15,190 8,738 18-75 6,090 18-b 772 19S 9.79 11-30 17-7 57-5 0-138 D.E. cylindrical, 155 1135 31,073 21,411 21-6 14,924 20-4 1543 16-? •?31 13-80 18-8 68-5 0171 (4D.E.1S.E. cyliu-) 1 drical, j" 155 812 24,908 12,851 20-5 10,517 19-9 1161 202 247 ll'lO 15-2 51-4 0-158 Belleville, 300 2200 67,800 25,774 22-0 22,547 21-5 2230 195 9.9A 11-50 11-7 .38-0 0-157 Do., 300 1460 40,990 16,961 20-5 12,785 19-8 1540 204 270 1100 11-6 4-^,-6 0-140 Do., 300 1390 47,300 19,156 21-0 14,049 19-9 1577 185 250 12-10 13-8 40-5 0143 Do., 300 1650 51,600 21,400 21-75 16,440 1800 ISS 245 11-90 13 0 41-3 0-150 Do., 300 2314 71,964 31,409 24-0 23,103 2500 178 242 12-00 13-6 43 6 0178 Do., 300 1610 50,300 22,360 22-7 16,100 1750 175 243 12-80 13-8 44-4 Mixed, Wo 1760 62,250 23,500 23-0 2250 215 .. 10-44 13-3 37-7 Machinery (2nd and 3rd Class Cruisers) Box, .... 30 504 12,748 4,500 15-12 611 304 7-36 900 35-4 0-200 Do., .... 30 455 12,420 3,878 1 14-82 640 370 6-06 8-52 313 0-209 S.E. cylindrical, 70 510 12,700 4,950 14-5 873 395 5-67 9-70 38-9 0-252 8 do. do.. 90 642 14,924 5,500 16-6 4,100 824 336 448 6-67 10 16 ;<7-n 0-219 Gunboat, - 110 388 11,565 6,151 18-0 4,-217 559 204 300 110 15-8 53-0 0157 4 D.E. cylindrical,. 155 570 13,830 9,653 19 0 6,215 18 0 049 151 234 14-8 16-9 70-0 0-2-20 Do. do.. 155 5-.'5 12,082 9,435 19 0 6,144 180 624 148 228 15-3 17-9 74-4 0-221 Do. do.. 150 575 15,641 9,271 20-5 7,423 19-3 748 181 226 12-4 161 .59-4 O-2-.'O 8 S.E. do., 155 624 18,579 9,846 20-3 8,307 19-6 915 208 247 10-8 15-8 53-0 0 210 Belleville, 309 869 25,606 10,272 20-0 7,155 18-7 825 180 258 12-8 11-9 40-1 0142 Do., 300 792 24,426 9,770 20-5 7,660 19-3 832 190 243 11-7 12-3 40 0 0149 Box, .... 30 210 5,980 2,170 12-8 236 244 9-19 10-3 36-3 0-152 6 S.E. cylindrical, - 60 244 5,8.50 2,139 i 13-0 350 374 601 8-9 36-6 0-165 Gunlioat,. 60 246 6,312 2,400 13 0 394 365 ;is-i 0-165 S.E. cylindrical, 90 301 9,254 4,030 14-6 3,131 517 300 370 7-8 Gunboat,. 1-20 213 6,400 3,365 10-5 2,201 290 197 301 11-3 15-8 52 6 0-207 Do., 130 2-22 6,836 3,754 16-5 2,462 353 210 321 10-0 10-9 65-1 0-216 Do., 140 244 7,878 4,613 17-5 2,647 395 192 334 11-6 13-9 5,S-4 0-242 Locomotive, 155 244 7,088 4,561 18-5 3,592 17-8 274 135 170 16-7 18-7 64-2 1-149 4 D.E. cylindrical, - 155 366 9,938 4,615 17-2 515 249 46-5 0-200 Do. do., 155 410 11,0-25 7,469 19-5 5,016 17-6 539 156 257 138 18-2 69-7 0-209 Express water-tube, 300 352 18,100 7,152 20-7 5,3S8 19-5 383 120 1.59 18-9 20-3 39-7 0 179 Do. do., 300 352 17,700 7,331 20-8 5,218 19-5 370 113 159 19-8 20-8 41-7 0-168 Do. do., 300 490 26,000 9,800 .. 524 MANUAL OF MARINE ENGINEERING. TABLE L5. — Particul.\rs op Cylinders. full Speed. Designation. When Built. 1 Kind of Engines. •a o a u g 3 Diameter, 1 .2 s > CU ■i S II H 1 Gunboat, 1876 1 ( Horizontal Keturn Connecting - Rod )^ \ Compound, j" ■2 Ins. 31-48 Ins 18 137 Ft. 411 Lbs. 23-8 Do,, 1889 1 Horizontal Direct-Acting Triple, - 3 20-30-45 24 184 736 36-6 Torpedo gim-l l)oat, i 1886 2 Vertical do. do., - 6 22-33-49 18 310 930 Do., 1890 2 Do. do. do., - - G 22-33-49 21 250 875 38-4 Do., 1890 2 Do. do. do., - 6 24-34-51 21 250 875 342 Vidette boat. Do. do. Compound, - 2 8^13 9 460 690 54-8 Torpedo boat. 1877 Do. do. do.. 2 9^15 9-5 435 689 47-6 Do., 1S77 Do. do. do., 2 121-21 12 354 708 46-5 Do., 1886 Do. do. do.. 2 18-30 16 402 1072 44-3 Do, 1887 Do. do. Triple, - 3 15-22-34 16 402 1072 36 4 Do., 1894 Do. do. Quadruple, • 4 14-20-27-36 16 410 1093 47-2 Do., 1893 Do. do. Triple, - 3 18-26-39J 18 370 1110 55-8 Destroyer, 1893 2 Do. do. do., ■ 6 18-26-39* 18 300- 1078 43-8 Do., 1894 2 Do. do. do., - 6 18-26-39J 18 393 1178 44-5 Do., 1894 2 Do. do. do., - 8 19-27-27-27 16 392 1046 60-0 Do., 1894 2 Do. do. do., - 6 19-29-43 18 366 1098 46-4 Do., 1895 2 Do. do. do., - 6 1S-27J-42 18 306 1097 42-2 Do., 1895 2 Do. do. do., - 6 18-27-42 18 397 1190 43-7 Do., 1897 2 Do. do. do., ■ 8 20-29-30-30 18 395 1186 56-9 Do., do., 2 Do. do. do., - - 6 21-32J-48 18 365 1095 53 '2 Do., do., 2 Do. do. do., - 6 19-29^-46 18 395 1185 52-1 Do., do.. 2 Do. do. do., - 8 201-31-34-34 18 392 1176 .50-0 Sloop, - 1899 1 Do. do. do., - - 6 16i-26i-42 24 200 800 40-0 Gunboat, 1898 2 Do. do. do., - - 6 11-17-27 16 286 763 55-3 Sloop, - 1901 2 Do. do do., ■ 6 lli-18-29i 24 200 800 42-6 MAClIIiNERY OF SMALL NAVAL SHU'S. 625 Machinery of Small Naval Ships. Boilers. Full P Tri owcr 4/5 or Natural Draught. AVei^'lit of Machinery. IMP. Full Speed per s ■:■ is Number and Kiud. 3 — 3 l.II.P. Speed. I.H.P. Speed. Total. U a. ^. 3 J3 ?5 11 o 3 OQ ■g ao ll Lbs. Sq.ft. Sq. ft. Knots. Knots. Tons. Lbs. Lbs. 2 Ouiilwat, CO 45 1,01S 519 10-0 79-7 344 6-51 11-53 50-9 0-233 Do., 150 68 2,200 1298 141 1033 12-4 108-3 185 235 120 19-10 59 0 0-135 4 Locomotive, - 150 121 4,426 2696 18-5 120-0 97 23 1 22-4 61-3 0-219 Do., - - 150 190 5,330 3840 20-0 2598 171-0 100 149 22-4 20-2 72-0 0-232 Do., 150 171 6,204 3665 19 0 2631 2110 130 178 17-3 21-4 591 0-2S7 1 Locomotive, - 146 5-5 235 151 15-0 4-0 OS 33-0 27 5 64-3 0-514 Do., 130 7 278 175 15-2 5-51 70-4 31-8 25-0 63-0 0-441 Do., 120 15-5 630 400 17-5 11-0 01-5 36-4 26 0 63-5 0-410 Do., 130 41 1,775 1013 19-0 31-6 70 32-0 24-7 57-0 0-500 Do., 180 38 1,660 1057 19-5 31-5 60-9 33-5 27-8 03-7 0-500 2 Water-tube Yarrow, 250 50 2,350 1600 23 0 32-0 6S-1 Do. do., 220 75 3,.50O 2300 23-5 48-8 47-5 47-1 30-7 66 0 0-377 2 Locomotive, - 180 100 4,656 3497 261 94-0 60 37-2 35-0 75 0 0-392 AVater-tube YaiTOw, 180 154 8,216 3884 27-6 90-6 52 42 -S 251 47-3 0-377 Do. Thoniycroft, 210 189 9,780 4368 28-4 108-2 56 40-3 23-1 44-7 0-438 Do. Normaud, - 175 150 8,800 4484 27-3 1-23 -2 62 36-3 29-9 50-9 0-440 Do. Reed, - 210 209 10,164 3885 27-9 llG-2 67 33-4 18-5 38-7 0-461 Do. Blechynden, 200 176 10,022 4367 27-4 106-0 54 41-1 24-8 43-6 0-400 Do. Thoniycroft, 220 196 11,855 5795 30-1 127 0 49 45-6 29-5 48-9 0-462 Do. Norman-i, - 220 210 11,945 6347 30-1 143-5 50 44-2 30-2 53-0 0-478 Do. Reed, - 250 255 13,384 6318 30-3 143-7 51 43-9 24-7 47-2 0-479 Do. Thornycroft, 250 245 13,561 6523 30-2 ■■ 126-0 43 51-7 27-5 48 0 0-4-20 4 lielleville, 260 135 4,020 14tiO 13-2 1120 12 0 1400 224 280 100 10-4 35-0 0-143 4 Yarrow, - 250 80-5 4,000 1300 13-5 960 130 95-0 164 13-7 161 32-5 0-136 4 Bahcock, 210 144 4.040 1404 13-5 1021 162-5 260 356 8-6 10-0 35 0 0-151 526 MANUAL OF MARINE ENGINEERING. Weiglit of Machinery. -T- Disulficoniont. i-l O lO Ci CO CO rH O 00 COCOi-H ■(Mrti'MCCiiOO] • (M • f-H O OCO rH 05 l^-CO CO ino Feet of Total Uoatintr yiirfHce. C^COCOCOCOCOCOCOCOCO-^CCrJiCOCO^ CO m -^ CO CO coio -^ Square Foot of Grate -<*< »o CO o CO ^- Ton Gross Register. COOCll^O-^OOcOt^-t-iOCO-^Or-t rH O lO 00 Cl -*0 CD Or-ltMO^lOi-tOOt^OCSt^l^CiOIr* W lO rH (M O lOO CO rH rH i-H O r-l r I iH i-H O rH rH O rH T Ton  Per I. H. P. ^ CO t-^i^- co cs •* r-( in CO O GO CO t-- O '^ Tji CO "* CO CO Tj< CO CO ''^ CO CO in "* (M CO CO (N CO &I Total. t-* CO O] O CO t:** 00 CO t^ G^ CO CO IM rH rH r-i O rH »n O CO rH O t- -rjl -^ lO CO Speed. ,j'.i-'toi?-'^';i.Jour-ouc;a:ji>-':;:jrH';oc!ijj oo M CM (M (M (M Total I.H.P. ooocooooooi— ct— ooinom o co o o o oo o ooo'y3ocooooin-^oo(MO'M co m o o o oo o -* CO CO CO c C-l CO C-l C^ CO Total Heating Surface. COiCOOCOmCOt^Or-l'f*<r icoi:--(Mi>-ooofMi>-oco -*  o" cT -^ "^"vrT in" <M (M (M CO 00 b- Til 00 *"O00OC0'*CDC0inOC0(MC0'*OOO • cocooocorH't*<oi>.a)(Mcoci»ncoin'>i c*coini>coo(>aoincococo(NirHiO'<*in , ,___ o 1-* in o 00 )cooocorH't*<oi>.a)(Mcoci»ncoin'>i in co o co i-t t- CO -^ CO CD OSCO r-i T-t CO C<1 00 OSCO rH rH  in CO co Ir- CD i^ Oi rH rH rH CM Sh ^ .f^^-^f^ .- .f^ „P^ ^H .g o o o o . • j3 '^ 'C 'O . ^^ 3 r£i H c« 15! bT. " _-• O O CO CO !y2 CO C CJ C» 1^ >.  I— |^n^nococc^-co^*ooi>t-- o CO o oi O) o Number of Revolutions. J m in CO in o in CO CO CO CD j^cooooo co oo 00 J>. Ir^ 05 CO CD t* CD 3 oo M* in o o CO o iOO OOrHOOOr-trHrHt^ 3COO-;KrHrHCirHr^rH J^^^ r^ Ci !"cO(>l<^C<]OOCOOrHCOCOrHCOQii ioci'Oo  rH Ttl CO in ^ CO 7— O (M J5 O O J^ rH CO ,■' J.^ rH CO ;J5^ IT l^ 05 ■?* cogs S "^ ^ S^i cs o TJ^-Iw^  eJ" co" in" in" nT (M <N C<1 f ooooo'^^clCicooo^-^-ocD^*Oln o in co o a -^co co Gross Register, oocDoococomcMOoiocoincoo rH 1-^ in '^ 1-* CO o oscocoocotMcom co" 1-^ J>^ c<r TjT iCi-T cd" TilOOOOrHi-HCOCO-^CDt--OOOCiO rH <M CO t^ OS O O *- ^- r- CO CO 00 00 00 00 OO CO CO CO GO O Oi <3> 05 O O O 05 O O _ COGOCOaOOOCOCOOOCOCOCOCOCOCOCOOO GO CO CO CO CO COO O o ' • ' 6 ' • ' - a a. I— t V, ' ■ cT ^'B • ■ S C3 O fcT 2 -g 1 o „ "5.2 CS o 1 £ P 1 p. § ■< o M « M M MACHINERY OF CARGO STEAMEUS. 527 Weight of Machinery. -h Displ icement. 00 00 r^. CO CO CO Oi lO CO lO C£5 «o ooo o o o loocoincoc-itccii-tco irt o o -o 10(1 F.ct of Total heating Surface. N(N<N (N (M CO CO COCC-fCO'^COC-lCOCOCO CO COCO Square Foot of Grate. Ton Gross Register. Ton of Machinery, CSO<M C-5 05(?J CO r*< iH lO ■** -J'COOCOCOO-^OCOO O (M O i-H I-'r*i!Z)ast>-t^(-^'*COrH l^ 5 M CO O iH 00 CO lO OOt- O I-- CO »p •* ooo o 1-t !:•* -^ ajOOt-COCOC/DCOOt>- t^ r-tO CO lO C-1 CD O O t^ CO lO C^D i.O W Tt* lO iC o lo CO  ■rt* CJ^r-t iO ■^TjiCOTpCOTttvO'^'^'^ -Tf -^lO (3 cs OOO <M JCOCOiOOO-rtt-rfCOCi 1- iCuO ^ CO o c; o ' CO lO rH lO coiomi^coooi^-^i i CO c-1 CO o 00 00 Speed. (^ p ip M ^CO W(>) Total I.n.P. OCi(M CO CJ '«1« O 030COOOOOOOO O QO O O OOCiO Ci CO  . lO 00 ai i-t (N rH IWCOCOOO-^COC^lt^CO rp CiO CO -^ Total Heating Surface. ooco o to O O OMOC-lOSCOp^OO O COOOO o ^■-J400 00 lO t* O COGilOr-irt<CS ._..00 CO OOCOGO o 1 CO -^ rH t^ O 00 i-^C-l CO_ «5^ . _ . ToT CO iSt^^r^ qS" < rH (-1 rH O^ rH C^ rH Tt< rH '^(MOt* CO -^ 1>- <M COCO(MCO(M'**Tt<(MCOCO CO OiCCJ'^ ^ • i-Ht^Tjioo COiOCi&l C CO rH c-l rH COOi-^OOGiO O  CO .oooo o oooo o .rHOrHrH O i-t ^ l^ ^ O (M c-l CI CM (N (N <M rH (M (M W H ?lH r3 ■3'-^ "3 ^«^ >» .Eh c "H m WHO g.a >= hm M -0<M <M CO<M O C-l M-" . -^ f-' (M — Referred Mean Pressure. H^C-1(M(M <M (M C<I (M <>JCOCOCOTtiCOCOCOCOCO CO Si)eed of Piston per Minute. . to o e-i 03 ■* (M ■^O-^OCOvo-^i^OOOiO ;D CO I^ 00 .»1i C > r-t CD (>J CO T-l O C lO lOCOlOCCI'-CDCOlOt^t^ t^ Number of Revolutions. IOCOU3 o m CD O l^CDI:^OOO0t^cC>t^O0t^ CD 1^00 stroke. ejOOOOt- CO O CD r^ CO O OO CO ■« iH Tf< OO ■* O CO -Hi-HCOCO oo »5'**^'*'rt CD CD CO o .*i*cDTa*.«sioiooTjiiocD CD in \n ^ ^ -est 00 (M CO t~ O CD #CD °P I O ■* 00 CD nwCDCD •«* CO CO O .^IITjiTjiCO 7"M cs -L^ >H«co* CO * . ^ ub^c;,-i,«4«i!?^ tS'S io -?:*•«. <r> CO (N (M CO  of Screws. N 03 M N oi Load Displacement. O O O OOOOCOOOOi 000 o oooo mot~oo ■ •^iCt>- CD 00 CO 1^ CDOiO.^1 i-i f-H i-t C<I rH ' r-i CI CI f-< CO I-H Gross Ucglster. oooor- 00 CO d ^ CO 00 (M i-( i-it^c75coo5t.-ooc;t^cD oi CO CI 00 m CD d ooC')cocox>i^Tj*in-t''»j' ■* ococdoq <M OO^t^^i-tOOOOuacDOCNOCD-^ 00^ <35 .* t^OO^ ■^ f-T co" n-^cSrooO'Z>-^ia'^'^ ccT co'c-fcoo" »noOO O iH CO -^ CDOOCRCJi*i.-cD — OOOO OOOO 00 00  ' ■ • 0" r ■ III • 02 rf:  III 1 ■3 0 '3 Ui a o" •E 0 0 c-l Apollo, Cuflc, - Ciizengo, Kovic, Kensingtc Oeorpic, K. Wilhel Othello, Cymric, K. Wilhel g CIS P. 0 c Saxonia, Runic, Somali, Celtic, i 0 528 MANUAL OF MARINE ENGINEERING, Weifrlit of Machinery, -r- Displacement. rH050^-.rHOi<35«C^O<MCOOCOCDOO'*r-tfHr- ailOCOC'3 00i-*C5COrHt^(N-<J1QOCOOCDCO»Oi-t OrHt-Hr-ti-tiH(NrHi-lr-iCOrHi-t<M(Mi-lC<ICOO]lM 100 Feet of Total Heating Surface. i-(;ooooocO'<*i(>DCir-tia-;i*pr*pp<NTjir-(^OTtiMiH^ OSOOOOOOOlOOOt^OOOOOOSOiOOQOWOOOt^i-'iHfM Square Foot of Grate. Ton Gross Register. Ton of  pq ^1 >OOT-tOI>-<:OCOOOrHCOCCir H O LO tH W .-H 1-1 O — - ■ — - -OCOOOrHCOCOi-lr. lOCOQOOCM-^CM .O-^ OOO Ol O -^ tH iCiCiCOfMCOTjiTflOCOMOOSOOOOlCOOIr^'^ ' rHC^l'^COCOl^.GOCOOiOOOOOiriCO'MOiOSO^OOO Speed. 4rHr-(i-(r-lrHrHi-li-l(M(Mi-HC>]CNr-l Total I.H.P. C5r-l'<#COOm(MO(MOOO!:OI^OOOOOOOOOOOO i-ti-ioqfMc^ii-Hi-irHi-iOTjti-iTtiTjimcoooiricst^co Total Heating Surface. •t^OTj*OOOOOOOOOOOOOOOOOOOC<10053 ttf i/^Oi-HOiOOOOCMC-lOOCOOmOfMU^OOOiOOt-'^OCS Grate. ^cou3i^t--ocoooo-*cioO'Mc;ooTjit*oi>ooqt^oocs ^w*. .. wj-jw^^^^ pH p-t rH oo O^ i-l CO (N CO f-H (N u^ CO <N tH Oa 6 .^66666666666666666666^ 3 .. g 'O 'C'd T3 XJ T3 ^3 'CO 'd '^ 13 'O 'O '^ 'O 'O 'd ^3 'd 0 H MQpqpqfiflp;«aficcQQcc^Qc«fip'^a3fl'oP o o Referred Mean Pressure. )-3(N«-i(M(N(M(MC^]C-5COCOCOOOCO'*COCOCO'*COCO-^ tUCO Speed of Piston per I Minute. I ?|rC']|--.OOO00'^C0I>.iOO00iOO(Nt--C0C0OO00tDC0C0C' Number of Revolutions. Or-lrHCOr^00500000(MOOOCO»OOCOir3000-^l>COI>-I> Number. Number of Screws. r^ffJ-Tt^COCit^tOOCSCOOtMCOCOCOeOCOCOCD-^COCOCOOCOO ^^ TjiOlc^COCOMMCOCOCOCO-^COCOCOCOCOOOCOO^COCOCOCOCOCO ) CO "^ . "* ■* ''9'?"?"?CONCOCOOit^-^>J^CS"*050CD'*co'^ 1 CM (M CO N CO CO oo H7i^-<^ ^^i 4« !?^ •^^:D (M CO C5 CO '^ m '* (MOOCOCNKNC^CONWCNrHlMc^ . ^ <M-^'^C<IlM'<*THTj)COCOCC)eOCOCOOCOCO^CC)«>CDCOOOOOCOCO r^(N<^3lHr^(^3<Mca^^^-^c<^I-lIH(^^<^^IH(^^N <M(NC<iNG<je3©fl Load Displacement. 000000000000000»AOO(MOOOOOO Oi-HO'*OOi000005l>-rHl>-aOI>-ii^I>-'^OTj*inCNOO ■r(100rHOC0C0l>OfMOl>C<ll>00l-^J>-(M'MC0(MI>'00r (Ni-lTHi-HrH<Mi-HG<li-li-lO](MC<l(N Gross Register. SOeOmr-lt^O-^OCMOiOOiOOi-fiaiMCO^OMOOtMCD l^COi>-u:5r- liOi— tCOI^-iOCSlOOTtiCOOOi— IGOCO-^-rtltOCO M10iOOOirHC<liCOOG<1000"^OOCOOt--**i-H':DiOOGOCO l-H i-H i-H i-l rH 1-1 i-l i-l i-i 1-4 iH 1-1 iH !N iH CN iH r-f When Built. JCSOffl'MCOirsOCOOCiOOOlC^lCOiCiOi-^t^-l^COOS^N -I^COCOOOQOGOCOCOCOCOOOidCiaiCiClClCiClCiCSOO 300CCCOCOOOCOC»COOOCOGOOOCOGCQOCZ)COOOCOCOCOCOOSO ^ .5 t." o o J .s e .ii e <s ■ .s; b-j 93, !^Pi I'ADDLE-WIIEEL STEAMERS' MACHINERY. P29 W o < 03 a Q Ph fa o K o O Pi ""J Ph pq <^ Eh Weit'lit of Machinery. -H L)isplacement. ^1 100 Feet of Total Heating Surface. Square Foot of Grate. Ton Gross Register. Ton of Machinery. Per I. H. P. Ji^^-i ^q coco cs^*pr^^^*^^^^-^^plpoooo05^* iOOCD05cOrH^-(^^(^^oo^..ocooo gJCO IP (M0OT)l<MCOCO'<K94(n'«'«-4l _ ^ CI ^^ CI o ■>! p ^ r* 1^ ci -»♦ »n ^ -^ 0-1 lO -^ CO CI -I' ^ gj ?0O OOCO OOi-H 0-*t~10-* coco OOOiHOCO o <f«rH0Or-COf^N<XH;-t-UJr-J;-CO-« . .i-cpoKp .KiO Total. § "=5 El Speed. Total I.n.P. Total rieatins Surface. Grate. _ a> i-i t-H i-H O •* LO I O -O .-H O -^ 1-1 ■ -*r^ o t^ -^ o o I I- .mo .0!M O . Ci CO . o o lO rH O CO C:5 ' S2 5-1 r-l TJ< (M OS } O CO •MO 00 O en PP't^*PpiHtOt~qOi^t*pippiO»oc1COOpOOO»pt^ ^ coot^^-i#cO(N(>ic3i^f^^C5iJ:5aiooc-i«-iC5t*^Ttf(fiA.i.^ Cq FHrHi-tr-lrHr-tiHrHrHrHiHOlrHr-trHrHiMWrHrHiHi-trHClCl 'l^ r^ C- iTi i.o •?! CO T-( »0 ' *i OOOgia)O00O00-*OOOOM '. O^O O O^C» O c5 CO CO CO CO K t^ t^ o o to c o c o o lOClt*«0«*:0C0OpOOCC0 ■tOr-IOI^'^OO •i-Hi 1-1 CO O CO ■» riff ■^jitoooeq iH Pressure. Referred Mean Pressure. Speed of Piston. ! 2 9 22 S S 2P ? o -"j-ooo o iot~oo o .oooo COCOCOOOC:it^t>t^COCOrHCO»OrHr-(-*UOCl li-lCOCO-^ '■■•'^ U^^- ■S'lpl . Ill -Ho is o o g o"H g § §hH^ o o o ija P5eqiH(N-*cq^T}ico-*coO(Moo^rH^-*eq(N^^ w '?>2pcO'P^pp'pp'OprH>pc-iipco(M-^ooocicooco "^ ?5l^capcoTt(Oi>r^oc;o^ociaocs4fior^(oaDi^t^o M <MlMMCOMCOCOS^ffqcO(MCOM.r5COCOCO^^COCO«CoSS = S2S^2ft222.9SSS:::!:J.^.'5 22r?2«=<»'opcop Number of Revolutions. Diameter. Displacement. Gross Register, When Built. cp^pOpOO^pt^QOrHCOpppCipUSOOOOOp ^ OOCWt^i t^ on>- rM oj o J, lO lO « op :0 rH 5 -41 00 c^ CD lA o CO frJ (M -«*( W CO ^ ■* o 00 o 92^ t^ (M D_ , O O rH (N O rH U3 '^^r* 00 O '^ ^ 3|H<»'nt-C0OOi-l"*-'-*O'-'^^ D lo CO • CO -.a o in 00 o <M iM ^', ^', ^^^^(^^^(^^^(NNfflNCON :n-<*cocon(Mcom o S O CJ s o I" "S ft-S .2 o d 6 6 d c d ' g-.2 H. d 5 d  -^ -.H ■OOOOIM i-H r-l rH O • CO c^ yj o C0C0tMC0>-(i000i-<irS'MC0Or»O< • o:oio>-Hinr*t^ioooscaooseoc i-tf-Hr-if-H i-H i-(C^O <N 1- i-l iM Ol Ol -1< lO r- r* t^ I- t^ t>- OO CO ■» O) X) 00 1^ c-1 >n 1^ Ci o t • IV O) ^ :0 : tCO'^-^COCOOCOOOt^ C:CdC^^C)0)0>C90dOO •ooaoco:ooo:OQOooo030oocooocoxoo 530 CHAPTER XXIV. WEIGHT — INERTIA AND MOMENTUM — BALANCING. Hitherto in this book little or no consideration has been given to the effect of the weight of any parts of the engine, although that of each one has some on itself and on its immediate surroundings, though generally it may be very trifling. The effect of the weight of some of the parts, however, is perceptible throughout the whole engine, and sometimes even makes its presence known from stem to stern of the ship. In the case of the propellers, both screw and paddle, their weight has been taken accoimt of in estimating the stresses on their shafts and the pressure on the bearings supporting them ; also the weight of the shafts themselves is not overlooked in considei-ing the dimensions of their journals, bearings, &c. But in calculating the sizes of shafts and propellers no reference has been made to the fact that their weight does to some extent modify the stresses borne by their parts. As a rule, however, the effect of mere weight is so very small compared with that due to the steam pressure on the pistons, cylinder covers, etc., that in ordinary engines it is and may be generally neglected. But the great increase in rate of revolutions in modern engines, and the demand for greater perfection in working, as well as the absolute necessity for it in many cases, have drawn more particular attention to the subject ; some most interesting investigations have been made by scientists, and from time to time methods devised whereby the ill effects due to the inertia of the moving parts of an engine may be modified or removed altogethei', so that it may be run at any speed without distress of any kind to itself or surroundings, and with perfect freedom from vibration. Fixed Parts — that is, those parts the centre of gravity of which have no motion but that due to the motion of the ship — may first be taken into consideration. The effect of their weight is simply that due to gravity, and acts always vertically. For example, the cylinder and its appur- tenances of a vertical engine rest on the columns, and by their weight increase the load on the columns; on the other hand, the stress on the bolts connecting them to the columns is decreased by it. When, however, the ship is in motion they have momentum, so that in case of a sudden stoppage by grounding or collision the tendency would be for them to move forward and shear the bolts, &c., and to bend the columns as well as strain the column bases and connections to the ship. The tendency is also of the same nature when the ship rolls heavily, but in this case motion is transverse to the forward movement. It is usual and advisable in all vertical engines, especially in tall ones, to provide for these con- tingencies by fitting ties of a more or less flexible nature from the cylinders to a suitable part of the ship. In a minor degree the same remarks are applicable to the columns, especially if of cast iron and heavy, but being MOVING PARTS. 531 lower down and sharing in the external support given to the cylinders by the ties, there is no need to do more than brace them together, as is generally done when the columns are of wrought iron or steel. By the above definition the shafting is a "fixed part," whose weight sets up in itself bending moments as well as shearing forces wliich may be sufficiently large to take into account with the twisting moment if the bearings are far apart. A rotating shaft has also critical speeds of whipping, at which the centi'ifugal forces become unbalanced; and although in the case of marine shafts dangerous stresses may not necessarily be set up, the result is a considerable amount of vibration and racking on the bearings. As a rule, greater stability is secured at speeds above the critical speed, but in marine practice it is perhaps best, if possible, to arrange for the critical spee^l to be above the maximum engine speed.* Moving Parts. — The effect of weight in these, however, demands the chief attention, and in quick running engines the greatest attention of the designer, not so much, as will be seen, for its static as for its kinetic effect. Some of these have simple rectilineal motion, others have circular motion, while a few have a combination of both, and move in an elliptic orbit; others, again, reciprocate on curved lines. The static effect of the weight of the piston, piston-rod, crosshead, and connecting-rod, is to increase the load on the piston on the downstroke and decrease it on the upstroke, in both cases uniformly. The effect of the weight of the crank-arms and pin (if unbalanced) is also to increase the down and decrease the up load, but not uniformly in this case. Tiie effect of the former is generally measured by dividing the weight in pounds by the area of the piston in square inches, and adding the result to the effective mean pressures of the steam on the top of the piston and deducting it from that on the bottom. This is shown graphically by drawing the diagram of effective pressures of the top above a reference line and that of the bottom below it: a new reference line is now drawn below the original at a distance representing the pounds thus ascertained and the ordinates measured from it used to determine the load on rods, ifec, and the twisting moments on the crank-shaft. Fig. 197 is the indicator diagrams from the high-pressure cylinder of a triple-compound engine 31 inches diameter; the weight of the piston, piston-rods, connecting-rods, Ac, is 5728 lbs.; dividing this by 755 the area of the piston in square inches, the constant downward pressure due * The sag or deflection of a shaft whose length between supports is L feet, its weight per foot of length MI pounds, and its radius r feet, is S = -0166 X ^ C - ) , E being the modulus of elasticity, 4-32 x lO" lbs. per square foot. And, if N be the critical speed of whipping, /115'5 N = V — V— for shaft supported on bearings. Example.— k shaft 10 inches (834 ft.) diameter Is supported on bearings 25 feet apart ; to And the sag , = .0166 X '''rr''!!^"' = -0131 foot, and N ^J^ ='JS = ^^'^ revolutions per minute. 4'32 X ICr * OloJ. 