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30 : THe Marine REVIEW A REVERSIBLE PROPELLER A reversible propeller for use in boats fitted with inter- nal combustion engines is shown in the accompanying il- lustrations. It was designed by W. E. Geyer, Cambridge, Mass. The propellers are made both with two and with three blades, the blades being pivoted upon the boss. The blades can be rotated and their angle relative to the shaft can be changed by means of a sliding piece. In the case of a propeller fitted with three blades the change in the inclination of the blades is accomplished by means of gears. The blades are set in a solid hub with a semi-. circular overhung rabbet, as shown in Figs. 1 and 2. - The hub slides longitudinally upon the propeller shaft. In each rabbet a slot A is cut which goes through to the FIG. I. GEYER REVERSIBLE PROPELLER. shaft. A pin B projects from the shaft through this slot and engages in a slot C cut in the propeller boss. The propeller flange is pivoted to the hub by means of a set of screws as shown in the end view of the hub in Fig. t. When the propeller boss is moved longitudinally on the shaft the pin B engages with the slot C and will rotate the flange about this set screw. The blade is cast in one integral part with the flange and rotates with the latter. Its angle of inclination, therefore, can be reversed by sliding the propeller boss along the shaft as desired. , HUB OF GEYER REVERSIBLE PROPELLER ) FIG. 2 The center of pressure of the blade lies between the set screw and the sliding pin. Thus the thrust of the pro- peller is divided between the two, the greater pdrtion be- ing taken by the pin which is an integral part of the shaft. But a small fraction of the total thrust is' transmitted to the boss and through it to the reversing force. This en- ables a solid shaft to be used instead of the hollow shaft which is usual in a reversible propeller. "The maker states that the main features of this propel- . ler are strength, reliability and ease of operation. The -- GEYER REVERSIBLE PROPELLER, blades are cut to a standard gauge, each being of the same weight. They form a perfectly true screw and balanced propeller. The hubs, blades and stuffing boxes are made of a good quality of bronze and are highly finished: The shafts are made of Tobin bronze. These propellers are made regularly in sizes from 4 in. to 24 in., larger sizes being made to order. se ee eee aoa ' MARINE METALLIC BOILER COMPOUND The Bird-Archer Co. of New: York and San Francisco has placed on the market a'marine metallic boiler com- pound which: has met with much success on the great lakes: "Very exhaustive tests have been carried. on during the past season.on the great lakes in the boilers of some of the Pittsburg Steamship Co.'s vessels, Corrigan, Mc- Kinney & Co.'s fleet and the Ceveland & Buffalo steam- ers--with most flattering results, especially in the latter vessels where the test has been watched with great care. On April 5 they began using the Bird-Archer marine metallic compound. The boilers of the ships were washed out the latter part of May showing a decided decrease of scale which had formed in the boilers the year before. There had absolutely been no new scale formed on the tubes that had been put into the boilers before the steamer started on this season's work, nor had any scale formed on the parts of the boilers that had been cleaned. A month later the opening of the boilers showed a still greater im- provement. In fact, the improvement was so great that the chief engineer decided not to open the boilers for eight weeks. This was something that had never been done before, as in seasons past they always opened their boilers from three to four weeks for washing out. Upon opening the boilers on Oct. 9 on the City of Erie, the boilers were found vastly improved over the for- mer opening, and on the City of Buffalo, a day later, the same conditions existed. | . The Bird-Archer people claim that it will not' be neces- sary for the Cleveland & Buffalo Transportation Co. to open their boilers for cleaning but once next season. This is made possible by the use of their boiler compound, and by a blow-off tube which Chief Engineer Rendall of this line has invented. It has assisted the compound wonderfully in removing the scale that had been thrown down, and the mud that accumulated in the boiler from _ the use of the Cleveland and Buffalo river water. This in itself will be a great saving to this company in' time and coal, as well as having the satisfaction of knowing that their boilers are free from scale, and are being grad- ually preserved by the formation of an amalgam, which forms over the interior surface of the boiler below the water line. There is no trace of scale on the tubes put in this year. This is considered a great card for the compound, for in years past, and using other compounds, by this time in their season's run they usually found from % to &% in. of this destructive stuff on the tubes or staybolts that may have been put in new at the beginning of the season. It certainly must be gratifying to the owners of steam craft that ply the great lakes, to know that there has been such a valuable discovery made in the shape of a marine metallic boiler compound, that will remove the scale from boilers, do away with the necessity of cleaning, and form this protective coating, which will preserve their life, they deriving from this a saving in coal and repair bills. In order to introduce the Jamaica banana in London, Elders & Tyffes, Ltd., upon the arrival of their steamer Chickahominy at Avonmouth, dispatch a_ special train to London with 14,000 bunches of bananas. The bananas were loaded into 100 vans and in a parade extending some half a mile in length crossed through a considerable part of the metropolis. The procession attracted a great deal of atténtion. It was projected for the purpose of showing how amply the bananas could be distributed to dealers.