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8 | MARINE Collapse of a Pair of Corrugated Furnaces. The illustrations on this page represent an accident that recently occurred to one of the four marine boilers of whaleback steamer City of Everett on the Pacific coast. They are reproduced from the Loco- motive, and they show the wonderful amount of deformation that a well made corrugated furnace can undergo without leading to a dis- astrous explosion. They also convey the lesson that unnecessary complications in valves and piping should be carefully avoided, since they are almost sure to result in trouble some time or other. The Everett is the only vessel of the whaleback type built on the Pacific coast. She was designed by Capt. Alex. McDougall, and was placed in commission in 1894. Her dimensions are 346 feet length, 42 feet 8 inches breadth, and 13 feet 7 inches depth. She has four com- pound marine boilers, each 182 inches in diameter and 11 feet long. The shells are of steel, 0.938 inch thick, and of 60,000 pounds tensile strength, and the pressure allowed by the government inspectors is 168 pounds per square inch. LEach of the four boilers has two corru- gated steel furnaces, 40 inches in diameter and 8 feet 6 inches long. The furnace shown in Fig. 1 is from the forward starboard boiler, both furnaces of which were burned: and bulged down by blowing the FIG. 1.--BULGED FURNACE. water out of the boiler while there was a fire in each of them. The blow off pipes from the four boilers are connected into cross, or thwartship, blow pipes, which pass over the tops of the boilers as shown in Fig. 2, and are provided with valves on the port and star- board sides of the vessel. It was this arrangement of the blow pipes that led to the accident under discussion. It appears that some time after putting out from Victoria, B. C., for San Diego, Cal., with a cargo of coal the engineer in charge or- dered the water tender, or fireman, to blow down 3 or 4 inches of water from the forward starboard boiler. In carrying out this order the fireman opened the valve on the front head of the starboard boiler, and also the outboard blow valve on the starboard side. (This will be understood by reference to Vig. 2.) After blowing down as far as desired, the top outward valve was closed. This, of course, stopped the blowing at once,but when the man came down from the ladder he forgot to shut the lower valve, on the head of the boiler. When the steamer reached Port Townsend, one of the breeching bolts on the forward port boiler was found to be leaking, and the chief engineer therefore ordered the pressure to be lowered on that boiler, and that water blown out so that the bolt could be renewed. He also gave or- ders to wash out the two after boilers, and carry steam only on the forward starboard boiler (the one on the right in Fig, 2.) As the REVIEW. Everett was to lie at the dock over night, a slow fire was kept under this boiler, the fires under the other three being hauled. When the steam pressure on the three cooling boilers had been reduced to about 20 pounds, orders were given to open the blow off valves attached to them and blown down. This was done, the blow off valve on the front head of the starboard boiler being open all os time ee it t was supposed to be shut. ps PORT BLOW-OFF STARBOARD BLOW-OFF aN ==) =a COLLAPSED FURNACES \ ANGLE VALVES FIG. 2.--CROSS SECTION SHOWING ARRANGEMENT OF BLOW PIPES, The result hardly needs to be told. The boilers from which the fires had been drawn were under only twenty pounds of steam, while the forward starboard boiler, with a fire in each furnace, was carrying 60 pounds, so that it emptied itself much more rapidly than any of the others. After some little time, one of the firemen opened one of the doors of the forward starboard boiler, and found the furnace red hot and bulged down as shown in the engraving. Upon investigation he found the other furnace in this boiler in the same condition. The fives were at once hauled out, and upon examination it was found that the furnaces were down 21 inches, the corrugation being pulled out so that at the bottom of the bulges the furnace was almost smooth but no signs of fracture could be discovered. If these furnaces had been poorly made, or if they had been constructed of a material deficient in ductility, it is almost certain that a disastrous explosion would have followed the rough usage to which they were subjected, and this fact ought to satisfy any one of the paramount importance in boiler con- struction of having good material and good workmanship. The folly of giving a fireman too many things to remember will, also be apparent, for if each boiler had been provided with its own separate blow pipe, discharging directly into the sea without any connection with the other boilers, this accident could not have happened. Waverly Salvage Case. In September, 1893, the freight steamer Waverly, bound fea Chicago to Buffalo, foe two schooners in tow, and 47,000 bushels corn as her own cargo, became disabled on Lake Michigan, by reason of a break in her machinery. The schooners proceeded under sail. The steamer blew signals of distress, and the Charlevoix, bound from Northport to Chicago, with passengers and cargo of general merchan- dise and fruit, came to her assistance. The matter of compensation was left to the owners for settlement. The condition of the weather was not such as to place the Waverly in imminent peril from that source, but there was sufficient sea to require care and skill, and in- volve some extent of risk to the Charlevoix in maneuvering to take the line and also in towing the disabled vessel, the wind having in- creased. The Waverly and cargo were valued, by stipulation, at $67,000, and the Charlevoix and cargo at $75,000. Judge Seaman of the United States district court, Milwaukee, decided that the service was voluntary, but prompt and efficient; it was more than mere tow- age, but only a minor order of salvage. A tender of $500 had been refused. The court allowed $1,500, saying "the purpose of the rule of salvage, which grants compensation in the nature of a reward, would not be fulfilled by narrowing the allowance so closely to the rate of mere towage," and that the amount awarded would be just under the circumstance shown. ; The season of painting is at hand and the Joseph Dixon Crucible Co. of Jersey City, N. J., asks everybody who is intending to pur--- chase paint to write for circulars and other information regarding Dixon's silica graphite paint. |