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288 THE MarRINE REVIEW July, 1919 TABLE II.--MEAN RESULTS OF EIGHT HOURS' run, at about 10 knots speed, to ascertain the power and the coal consumption for that speed, so that the radius of FULL-POWER TRIAL, MAY 28, 1910. Starboard... Port. action, with the normal supply of coal} Mean steam in boilers ser ee eae eee ee ia ne ee ve eens ok 248 Ib. a a He os Oe ih vkidn ee "0.49 in. on board for such cruising speed could =e cut-off oe Oe cline ee i ee ee 573, be arrived at precisely. The mean re- AM WACOM CE ees oe dos ok orc oan Fie bee Ce See Solent ge sidse nue% F . : an : Uy arg oe SR ge a) ee 138.6 ae sults for these trials are given jp High PBR lak woe le oh wer AO Re io eB cp ah 86 ecole a8 eid Ola due 44086 89.24 oar Table I. -Mean pressure in PMtetINediate 6 eee Pe eee hee eas ve es rey aie cylinders. (Jb.) upee Bla PS ee a eae es es aD A week later, the 'vessel proceeded on : Weg LE ca iow he, 6.5.60 5 0 6 6 0.0 6/0 bn 9 wie 6.0.0 656 859.60 0.8 608 7. ' : i : Be eek, pee Fie, a trial of eight hours' duration. The ae ge ori Ra Ea oe 2,153 2024 conditions in this case were that the RO ie ee ee 2,118 Bt) pion cpeed 'shauld not exceed 1000 & tet sndicated "'horeenOwer. 6. 56 5. a es ee 10,616 ee 10,868 per minute, the steam pressure 250 Ibs, Bad teccpowe: pe hour De ee 1.42 Ib. the air pressure in the stokehold % in,, Water loss per 1,000 i. h. p. per 24 hours = 2.2 tons. The heavy guns are mounted in barbet- tes with 12-in. and 8-in. armor, and the mechanism is covered with hoods. The several 4.7-in. guns, arranged on each broadside, are protected by the 9-in. armor, while the remaining guns on the upper works have shields. In the third place the full speed at- tained--21.623 knots--practically equals the average rate attained by the British Dreadnought battleships, although special care had to be exercised in the design of the machinery in order that the steaming conditions might be easily met when using such coal as is readily available in South America, since this may not al- ways be of the high calorific value of the better anthracites, and in order a.so to meet any deficiency in the skill of the stokers. Thus, for instance, the proportion of heating surface to grate area is about 36 to 1, as compared with from 30 or 33 in the British service. As a consequence, the boilers of the Brazilian ships are larger and _ heavier for a given power, but there is gain in greater reliability under the conditions of South American service. Recipro- cating engines have been adopted and- have proved of high efficiency, the radius of action, according to the results of the Sao Paulo trials, being 29 per cent greater than that guaranteed--or 12,913 nautical miles instead of 10,000 at 10 knots. The full speed on trial -- 21.623 knots--was realized with 28,645 i. h. p., while the guarantee was for 21 knots. On a trial of about four hours' duration, during which six runs. were made over the measured mile, a speed of 2114 knots was attained with 25,517 i. h. p. On an eight hours' trial a speed of 20.99 knots was got with 22,355 i. h. p., the guaran- tee being 20 knots. There is thus the important advantage of a reliable high speed as well as a wide radius of action, added to offensive and defensive qualities of a high order, with a draught of only 25 ft, whereas in many of the later foreign Dread- nought ships the design is for draughts ranging up to 29 ft. and 30 ft. It is obvious that, especially in South Amer- ican waters, the Brazilian ships. must 'Lotal bunker. CApAClLY 320. oes ce ee ies 5 «Fee ee ele 3 and the coal consumption 2 lbs. per i, h. p. per hour. The mean results are shown in Table II. It will be -seen that with a piston speed of 970.9 ft. per minute, a steam pressure of 248 lbs. and on air pressure of 0.49 in. the average power developed have a great tactical advantage in action. It should be remembered, too, that it ig easier to find docking facilities where draught is thus limited. The principal dimensions of the two vessels are as under: Weeteta Over alia ee ee oe ss MS ee 543 ft. Isength. between perpendiculats 6 sy 20. ce. chee see 500 ft. WT OACE, TOIGCO 45 es Ou hc ooo a Sic eee ve 6 chia e ee 83 ft. Wepti miolded ie are wow een e's Att) San: UDA ee ed oe nas Grass Cy hace Cae baie Cee 0% 25 ft. Displacement ab. 2o-tt. GTrauoht ce. bial sek ile ee ee 19, 280 tons. WPEEG at Julleepower resol ae Soe ce oe oe ee he ules 2k 623 knots. dindicateds Morsepower 240555 sik Folch sale eee ce eas 28,645 i. h. p. 800 tons. 2,360 tons. 12,913 sea miles. Normal coal capacity on 25-1t. 'draught 2.2... ...06.0.05. 2. Radius, of action determined on 48-hours' trial at 10.6 knots : ARMAMENT. Twelve 12-in., 45-calibre guns. Twenty-two 4.7-in., 50-calibre guns. Eight 3-lb. guns. - ARMOR. " POAC Side fr oe Se Sn hee Ss oc eo ween es 9-in., 6-in. and 4-in. cemented steel. REGUeChive CCCk oe ai es ro es uss eee ee beds : 2° in, Wise itieat a gee es ls Oe ees ck ae ees 9 in. Gunebarbettes. ay kee Noo Set Sera grate < 12> in. Forward and after athwartship bulkheads BC geen Oe were 3.in. and 4: 1n. Machinery--Engines, triple-expansion, four-cylinder type. Diameters of cylinders:--High-pressure, 39 in.; inter- mediate, 63 in.; and two low-pressure, 73 in. Stroke, Sots 6. in. Motal Cools surrace of condensers' so. 02.5... eee ce. 24,000 sq. ft. Boilers, eighteen of Babcock and Wilcox type. dleabinier Suriicen fs re eo ee oo 58,370+sq. ft. (Grate (area fe ene ie, es ee ee 1,686 sq. ft. was 21,484 1. sumption was only 1.42 Ibs. h. p., while the coal con- and the The trials of the Sao Paulo were commenced on May 21, with a 48-hour TABLE TIl---RESULTS OF MEASURED-MILE TRIALS. Revolutions per ---_--- Indicated horsepower. Speed, Total Knots. Starboard. Port. inp. No. of minute. ----- Run. Starboard. Port. St% RUNS AT FULL POWER, FOR 1,000 FT. PISTON SPEED, %-IN. AIR PRESSURE, 250 LB. STEAM PRESSURE. ee ee te als) 140.9 139.5 20.571 11,234 10,840 22,074 Oe ee 141.2 139.1 21.352 11,360 10,876 22,236 ee ee 141.4 140.9 20.477 11,353 11114 22,467 A ge 141.5 142.2 21.505 11,223 11,628 22,851 RO ee 140.5 141.3 20.618 10,974 11,440 22,414 Ber 140.5 141.2 21.453 10,762 11,330 22,092 Weeans ce kc ee 141.0 140.7 Mean of 115151 11,204 22,355 ---- 140.85 ----_ means 20.99 : Six RUNS Al FUEL SPEED WITH 250 LB. STEAM PRESSURE. Loe oe 145.8 145.5 21.617 12,631 12,828 25,459 a 143.3 142.6 20.979 12,039 13,404 25,443 Soe ee 144.8 144.5 21.302 12,393 12,542 24,935 Ce ee 148.0 145.9 21.052 13,027 12,712 25,739 See, eee. 146.3 147.1 21.686 12,913 12,992 25,905 Oe eee 147.5 145.8 20.93 13,038 12,586 25,624 Means 06 6 ee es 145.95 145.23 Mesn of 12,673 12,844 25,917 ---- 145.59 - means speed 21.231 TWO RUNS AT FULL PRESSURE (280 LB.). eee ee 152.8 151.4 21.428 15,301 14,648 29,949 De 149.8 149.4 21.818 13,593 13,749 27,342 as. 151.3 150.4 Mean of -- 14,447 14,198 28,645 -- 150.85 ---- means 21.623