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MARINE REVIEW. 87 Value of the Indicator. About the middle of last season a large triple expansion en- gine in one of our Cleveland steamers suddenly lost three revolu- tions a minute, so that instead of making her usual 80 revolu- tions per minute, only 77 could be obtained, while her coal bill was considerably increased to get even that number. This was a bad state of affairs surely, but as it is one that occurs through the wear and tear of certain parts of an engine, the usual remedies were resorted to. The eccentrics on the main shaft were exam- ined to see if they had shifted; covers of the high, intermediate and low pressure steam chests were taken off to see if any of the ~ valves had slipped on their stems. But, no! Every thing looked to be allright. The valves had the correct amount of lead on both centers. Up came the cylinder heads so the en- gineers could look at the piston rings. 'They were also in good shape and did not need setting out. 'The air pump and vacuum guage were then examined and found to be in good working order. Still the engine was not doing her work, and the steamer was not making her time, while the firemen were '"'sneaking"' the blower on at every opportunity to help. to keep up the steam. Fortunately for his reputation as an engineer the chief was working for an owner who would listen to an explanation, so _ instead of his being discharged by the captain because be could _ not "drive her," the owner and captain, agreeable to the chiet's _ suggestions got him a good straight "lyne" indicator. This was applied to the engine and here are the cards obtained while run- _ ning at full speed through the lake. H.P. CYL, | Spring 80 L.P Cb. SPRING 40 Ear ey ic. SPRING 8. ee eg a eae Particulars of cards: High pressure--diameter of cylinder 20 inches, stroke 4o inches, cut, all off, scale of spring 80; Intermediate--diameter of cylinder 32 inches, stroke 40 inches, cut, 1% in. on, scale of spring 40; Low pressure--diameter of cylinder 52 inches, stroke 4o inches, cut, all on, scale of spring 8; Steam pressure I50 ee Throttle wide open; Vacuum, 20 inches ; Revolutions per minute 7 Card number 1 from the high pressure cylinder indicates | everything there to be in good shape, although a freer exhaust - would be beneficial, Card number 2 from the intermediate shows that a little more lead would help some, while card number 3 from the low pressure looks as if that engine was doing as much work as a wooden-legged soldier in the fire holdin a gale of wind. The low pressure was where the indicator located the trouble; and knowing that the rings were set out plenty tight enough, the steam chest cover was again taken off, when on a very Close examination it was discovered that the valve stem had sprung off from the valve seat, carrying the valve with it, so tightly, was it keyed on the stem, causing a direct "blow through" ofithe steam under the valve into the exhaust port. 'The trouble was easily remedied and the valve allowed to face up on its seat again when the usual number, 80, revolutions were again obtained, much to the relief of the "smokers" and satisfaction of the cap- tain and engineers. fou 2 1Est The vacuum gauge showed a vacuum of 20 smote all that could be obtained with the attached air pump in use when work- ing strong. Of course with an independent air pump and con- denser a vacuum of 26 inches could have been malntaied paglly but to quote Kipling, "That would be another story." Pt The engineers in the line boats out of Buffalo are given an indicator by the management and are ordered to hand in as 'part of their report, cards taken from their engines every trip... "But the majority of the steamboat owners of Cleveland are at present unaware of the value of the indicator to them as a saver offuel, for very few of them furnish or require one to be used. © But'ad- mitting that fuel is no object to them, the indicator as' an impor- tant factor in getting out of an engine all that is in it, should be a big recommendation for it to be placed in the. hands. of the Cleveland engineers. S.-i. H., Marine Engineer. i Locate Obstructions. 1 ott sabad It has been suggested repeatedly during the past reg seasons that masters of deep draft vessels carry a buoy of some kind with line attachment, to be thrown overboard in case an obstruction of any kind is found in shallow parts of the lakes. During'the coming season some work in the way of surveys will very'pro- bably be made in certain localities, and in all of the districts the naval officers and engineers will do all in their power to locate any sunken rocks or wrecks that may be reported to them. _Ves- sel masters should co-operate in this movement. Commander Ludlow, Chicago, writes as follows to Capt. Geo. P. pease on the subject; Capt. George P. McKay, Dear Sir:--As you are in position. to meet many of the masters of the vessels engaged in running to Chicago and other ports in the Ninth light-house district, which comprises Lake Michigan, Green bay and the Straits of Mackinac, to Old Mackinaw point, I would be obliged if you would request all masters who notice obstruc- tions to navigation which are not on the charts, to inform me as soon as possible. I shall be in the government steamer Dahlia during | most. of the season, and when time can be spared from the legitimate duties of the vessel, shall endeavor to locate as accurately as possible any dangers, rocks, shoals, wrecks, etc., that may be reported to me. I would like to impress upon those who discover dangers, that in re- porting them, accurate ranges of well known objects are the best to lo- cate by, which can be supplemented by compass bearings corrected to give true bearings. The compass errors in some of the lake vessels are so great that little can be made out of uncorrected bearings. It has been already reported to me that a shoal exists six miles south (true) of Skilligalee, with 17 or 18 feet of water overit. This I shall try to hunt up this season. The Roumania shoal and the obstruction found by the Pana in 1890, can hardly be the same, if the data given is anything like correct. There may be two or even more shoal spots there. NIcoLL LUDL Ow, Commander U. S. Navy, Inspector Ninth light- house district. If you will send your name and address to the J. L. Jackson, foundry and machine shop, Saginaw, Mich., and mention ,the MARINE REVIEW you will receive a morocco covered memo- randum book that contains valttable mechanical tables and ew lations,