May 19, 1892.1 



FOREST AND STREAM. 



483 



weights, the engine would still be balanced vertically but would be 

 unbalanced horizontally. 



I would now direct your attention to Figs t to 9, showing the cal- 

 culation as applied to triple expansion vertical engines. The most 

 suitable positions are first determined for fixing the two eccentrics 

 which give motion to the bob weights, in tbis case the one lettered X 

 being at the forward end of the engines and the other lettered Y 

 being between the low pressure crank and its valve eccentrics. Each 

 unbalanced moving part iu the engine is then dealt with separately, 

 as before described, and the position and amount of the weights 

 necessary to balance is asw rtained, the stroke of the baJauce weights 

 being taken, for the purpose of calculation, as equal to the stroke of 

 the part they balance in each case. For instance, take the middle 

 pressure piston, piston-rod, etc . lettered B, the unbalanced recipro- 

 cating parts of which weigh 1621 bs., the balance required at X is 

 found to be Sl.blbs. and at Y 80,21bs., the stroke of each being 16in. 

 Taking auotber instance, for example, the high-pressure valve and 



balance weights on the cranks only, and (3) with balance weights on 

 cranks and bob weights, The amount of vertical vibration at the 

 stern, as obtained in the river, is given in Fig 8, together with en- 

 larged vitrometer diagrams, from which it will be seen that tne 

 results corresponding to the three conditions show a vibration of 

 37 M in. a= usually made, 9 %4ta. with balance weights on cranks, and 

 7 04 in. with balances on cranks and bob weights. I have not the 

 slightest doubt, from more recent experience, that this small vibra- 

 tion that remained could still further be reduced, and in fact practi 

 cally avoided altogether by taking greater care in accurately ascer- 

 taining the weight of all moving parts. Tl e foregoing trials were all 

 made at 248 revolutions per minute, which corresponded in this boat 

 to the speed producing maximum vibration, that is to say when the 

 movement of the engine synchronized to the greatest extent with 

 that of the boat. I believe that the vibration of the largest Atlantic 

 liner can in this way be practically overcome by the expenditme of 

 a few hundred pounds, if carried out in the original design. 



Fog, JL 



VERTICAL VlBR ATI 0 N 

 AT S T E R N, 



ZT AS w OSUALLV 

 64 CONSTRUCTED 



ALA.NCE WEIGHTS 



on -cranks^only 



BALANCES ON" CRANKS 

 4> BOBJYEIGHTJ 



its go-ahead gear, lettered E, weighing 264.51bs., and at Y 36.251bs., 

 the stroke of each being Sin. After dealing in a similar manner with 

 all the reciprocating parts, if we were to construct two uniform dises 

 with each of the weights thus found Dinned on in its proper relative 

 position, and place them respeciively at X and Y, the engine would 

 be balanced vertically. All the weights at X might be, replaced by 

 one large weight equal to the sum of them, and having ihe same 

 position of center of gravily, in a like manner the weights at Y may 

 be dealt with These are shown by the large black spots on the 

 diagrams. These again might be substituted by larger or smaller 

 weights, as convenient, situated nearer to or further from the center 

 of the shaft, the amount of weight being in the inverse 

 ratio to the distance from the center. It will be seen that in the 

 present case the total weight of all the balances equalled 740 251bs. at 

 X, and H78.151bs. at Y, and the distance of their center of gravity 

 from center to shaft was 1.04in., and .28in. respective] y; these would 

 be equivalent to a rotary weight of 4131bs. at X, with its center of 

 gravity l%iv. from the center of the shaft, and a rotary weight of 

 131lbs at Y, with iis center of gravity SJiin. from the center of the 

 shaft, these two weights would balance the engine vertically, but 

 would set up side vibrat'on. To avoid the latter and retain only the 

 vertical effect, the use of bob weights equal to the rotary weights, 

 and having the same veriical motion, ana in the same relative posi- 

 tion on the shaft, are substituted. This method was adopted in the 

 engines we shall refer to later on. 



The correctness of this mode of calculation is confirmed by exper- 

 ience in practical working, The exact amount, position, and stroke 

 of the bob weights can be accurately calculated in the original de- 

 sign, and if they be made accordingly no vibration will take place at 

 any speed. The calculations are simple, but care must be taken that 

 they are based on accurate data. To estimate the weights of the 

 reciprocating parts from drawings is not sufficient, they should be 

 ascertained by actually weighing the finished ariicles. 



Triple expansion engines with three cranks, although partially 

 balanced when at rest, are very far from balanced when at work, 

 owing to the distance between the various reciprocating parts, which 

 consequently set up a rocking motion which is the principal one to 

 be overcome, and in such engines this rocking motion we have to 

 deal with in addition to the vertical motion of the center of gravity, 

 this vertical motion being due to the difference m weight of the work- 

 ing parts of the three engines. The positions of the bob weights 

 should be chosen so as to minimize their weight. What weight may 

 be necessary to avoid vertical vibration of Che center of gravity is 

 - constant, but what may be required to avoid rocking motion is 

 diminished by an increased distance apart of the weights. In double 

 cylinder engines with cranks at right angles it is a more pronounced 

 galloping motion, i. e ,a motion of a complex kind, being a compound 

 of vertical motions of their center of gravity and a rocking motion. 

 In a single cylinder engine the vibration of the engine is practically 

 up and down. But with whatever type of motion we have to deal 

 the same principle of balancing holds good. All forces causing ver- 

 tical vibration can be neutralized by the use of bob weights, arranged 

 • to set up equal forces acting in an opposite direction. Some years 

 ago we thought the vibration in triple -expansion engines was due to 

 the difference in weight of the pistons, and with a view to balance 

 them, and, as we supposed, avoid vibration, we made each piston of 

 the same weight in a first-class torpedo boat; thus we prevented any 

 vertical movements of the center of gravity of the engines, yet we 

 found no improvement. This clearly indicates that the rocking 

 vibrations are of more importance than the vertical vibrations in 

 triple-expansion engines. 



There is one feature about the vibration of vessels which deserres 

 attention, viz . that it varies in intensity at different points in the 

 length of the hull; there are places where it is excessive and places, 

 termed nodes, where it does not exist. 



I will now refer you to Fig- 10, representing some engines indicat- 

 ing about 1100 horse power, for a first-class torpedo boat, 130f c. in 

 length by 13ft. 6in. beam, having a speed of from 22 to 23 knots, 

 carrying a load of 20 tons. There is nothing special about the 

 engines, excepting the two eccentrics fixed on the shaft at each end, 

 working vertical hob weights. To the cranks were fitted weights 

 sufficient to balance them,' the crankpins, and partially the connect 

 ing rods. How far each connecting rod was balanced by rotary 

 weights was determined by its weight, and the lateral movement of 

 its center of gravity ; what remained unbalanced was balanced oy 

 the bob weights worked by the eccentrics, their stroke and weight 

 being calculated as already explained when describing Figs. ■; to 9 

 Experiments were made with this boat in the Thames and also in the 

 West India Dock. We tried her under three conditions, (1) without 

 any balance whatever, as engines are usually constructed, (2) with 



Bob weights proportioned and arranged, as already described, may 

 be reduced in amount if wished, being substituted by a rotary bal 

 ance weight equal to such reduction; this, however, must not be car 

 ried out to an extent to produce sensible side vibration. 



Thinking it would be of interest to the meeting, and in confirmation 

 of the statements put before you, I propose to throw on the screen a 

 series of instantaneous photographs taken while our experiments 

 were be ! ng carried on. In all cases the revoluiions were 248 per min- 

 ute, and it is the ripples on the water produced by the vibration of 

 the boat to which I would direct vour attention. 



Photograph No. 1 shows the effect at the bow without any balance 

 weights as usual. Photograph No. 2 shows the effect with boh 

 weights and balance weights on cranks as described. Photographs 

 Nos. 3 and 4 show the effect at the stern under a similar set of condi- 

 tions, viz.. without any balance weights, and with balance weights 

 and bob weights respectively. Photograph No. 5 gives a broadside 

 view without balance weights, from which not only can the disturb- 

 ance of the water in the immediate vicinity of the boat be seen due 

 to its vibration, but the points where the vibration is the greatest and 

 the position of the nodes, where there is no vibration. Photograph 

 No. 6 shows the boat under exactly the same conditions with balance 

 and bob weights, in which the disturbance of the water is so small as 

 not to be noticeable in the photograph. To show how easily a boat 

 of this description may be set vibrating when the number of impulses 

 correspond to its natural period of vibration, I beg reference to pho- 

 tograph No. 7, showing the vibrations produced by simply one man 

 springing on the stern. To further illustiate the system and prove 

 its correctness, I nave here a model corresponding to a triple-expan- 

 sion engine, the weights of the pistons have been similarly propor- 

 tioned to one another as in our torpedo boat engines. It will be seen 

 that the shaft is made to revolve by a flexible wire so as to avoid the 

 result being vitiated by the node adopted for causing it to revolve. 

 This model engine is suspended on springs in order to be quite free 

 to move vertically. You will notice when we set it going that unmis- 

 takable vibration is at once set up; the rotary weights, such as crank, 

 crank pin and lower end of connecting rods are all carefully balanced 

 by balanced discs, and consequently this vibration is due to the verti- 

 cal moving parts. We will now connect the bob weights, on each 

 side, the amount, stroke and position of which have been arrived at 

 by a similar calculation to that already described. The effect of 

 these bob weights in completely avoiding the vibrations will be 

 clearly seen. 



In conclusion I would desire to thank those members of my staff 

 who have been occupied with me in carrying out these experiments, 

 Mr. Cronin, Mr. Nesbittand Mr. Marriner, for the able way in which 

 they have assisted me in the investigation I have had the honor of 

 laying before you this evening, which I hope you will consider of in- 

 terest. 



LAUNCH OF THE CORSAIR. 



CONSIDERABLE interest was manifested at the yard of Summers 

 & Payne. Belvidere, Southampton, on April 20, when the 40- 

 rating racing cutter, built for Admiral the Hon. Victor Montagu, of 

 Wherwell Priory, Hams, was launched. She is from a design by Mr. 

 Arthur E. Payne, and was named the Corsair on leaving the ways by 

 the youngest daughter of the owner. The yacht has the now "fash- 

 ionable Roman nose stem, which is introduced into the Decima, 

 Siola and other racing boats of which Mr. Payne is the designer, and 

 outside is painted white, with a gold stripe. The mast is placed well 

 forward: she will have a large mainsail, and she is a very beamy 

 boat. Her fittings below are chiefly iu white, with polished cedar, 

 and her accommodation includes a good saloon, two sleeping berths 

 in the steerage, and a ladies' cabin aft, making up four beds alto- 

 gether. There a captain's cabin and forecastle, and all below is very 

 light. The fittings on deck are chiefly of cedar, and she has one of 

 Cante'o's patent capstans. The Corsair's canvas will be supplied by 

 Ratsey & Lapthorn, and as previously announced in the Meld, she 

 will be sailed by Svcamore, who in previous seasons has had charge 

 of The Babe. 2^-rater. There was a large number to witness the 

 launch, including the owner and his wife (Lady Agneta Montagu) and 

 family, also a strong muster of the yachting skippers of the port, 

 who were all pleased with the trim of the Corsair, and also her ap- 

 pearance; while there was a great deal of criticism with regard to her 

 increased beam, as compared with some other 40-raters, and various 

 opinious were expressed with reference thereto. The yacht was 

 launched with her mast stepped and her topmast half hoisted, her 

 racing color— red, with black star— surmounting the latter. The 

 Corsair was taken alongside the new and spacious ietty which has 

 just been completed at the yard to finish her outfit.— London Field, 



FIXTURES. 



MAY. 



21. Winthrop. 3d and 4th Classes, 30. Eastern, Special, Marblehead. 



Winthrop. 30. Cape Cod, East Dennis. 



•21. Corinthian. Atlantic City. 3J. South Boston, Open, City Pt. 



21. Miramichi, Picnic and Sail. 30. Fall River, Fall River. 



28 31. Oswego, Cruise, Gt. Sodus. 80. Douglaston. Opening, Little 

 28. Rochester, Opening Cruise. Neck Bay. 



28. Lynn, Expert Cup, Lynn. 30. Knickerbocker, Opening, Ool- 

 28. Buffalo, Opening. lege Point. 



28. Quincy, 1st Cham., Quincy, 30. Kill von Kull, Opening. S. 1. 



Mass. 30. Brooklyn, Opening, Graves- 

 30. Larchmont, Special, Larchm't end Bay. 



30. Corinthian Mosquito Fleet. 



JUNE. 



1. Cor. Navy, Ann,, Glen Cove. 18. Corinthian, 21ft. Class, Mar- 



1. Winthrop, Pen.. Winthrop. blehead. 



1. Monatiquot. Opening. 18. Savin Hill, 1st Cham. 



4. Philadelphia, Ann., Del. River 18. Winthrop, Ladies' Race, Win- 



4. Larchmont, Spring. Larehm't. throp. 



6. Corinthian, Atlantic City. 18. Quincy, 2d Cham., Quincy, 



7. Wintbrqn, Moonlight Sail. Mass. 



9. New Yofk, Ann., New York. 19. Winthrop, Sail, Winthrop. 



9. Rochester, Squadron Review. 20. New Jersey, Ann., New York. 



9. Miramichi, Cup, Newcastle. 

 11. Cor Navy, Glen Cove. 

 II. Marine & Field, Ann., N. Y. 

 11. Buffalo, 1st pennant. 



13. Pavonia, Ann., Communipaw. 



14. Atlantic, Ann., N. Y. Bay. 

 1(5. Rochester, Ladies' Day. 

 17. Hull, Class 4, 5. 6, Hull. 

 17. Mos. Fleet, Club, Boston. 



17. Winthrop, Cham.. Winthrop. 

 17. Cape Cod, Open, East Dennis. 



17. Beverly, Monument Beach. 

 18 Eastern, Marblehead. 



18. Dorchester, Dorchester. 

 18. Mos. Fleet, Cham., Boston. 



20. Winthrop, Tender, Winthrop. 



22. Winthrop, 3d and 4th Classes, 



Winthrop. 



23. Rochester, Club Regatta. 



22. Rhode Island, Ann. Regatta 



and Ladies' Day. 

 25. Chelsea. 



25. Indian Harbor, Open sweep, 



Greenwich. 

 25. Hull Cor., 1st Cham., Hull. 

 25. Brooklyn, Spriug, Gravesend 



Bay. 



25. Buffalo, Ladies' Day. 



27. Eastern, Ann., Marblehead. 



30. Savin Hill, Open Race. 



JULY. 



1. Miramichi, Cruise to Nequac. 16. Hull, Classes 3, 4, 5, 6, Hull. 



2, Rochester, Ann. Cruise, Oak 16 Mos. Fleet, Cham.. Boston. 



Orchard. 16. Winthrop, Ann. Cruise. 



2. New Rochelle, Ann., New Ro- 16. Dorchester, Dorchester. 



chelle. 16. Beverly, Monument Beach. 



2. Seawanhaka, Ann.. Oyster Bay 1>. Cape Cod, North Dennis. 

 2. Hull, Class Race, Hull. 18. L.Y.R.A., Oswego. 



2. Savin Hill, First Cup. 21. L.Y.R.A., Rochester. 



2 Mos. Fleet, Cham., Boston. 21. Rochester, L.Y.R A. Regatta. 

 2. Winthrop, Open, Winthrop. 22. Corinthian, Atlantic City. 



23. Monatiquot, 1st Cham.. Ft. Pt. 

 23 Corinthian. Marblehead. 

 23, Hull Cor., Hull. 



4. Corinthian, Marblehead. 

 4. Larchmont. Ann., Larchmont 

 4. Buffalo, Open. 



4 Douglaston, Ann., Little Neck 23. Sippican, Club, Marion. 



Bay. 25. Rhode Island, Cup. 



4. Boston City. Boston. 25. L.Y.R.A., Hamilton. 



4. Beverly, Monument Beach. 27. Royal Can., L.Y.R. A., Toronto 



4. Quincy, City of Quincy Re- 28. Queen City. L Y.R. A.. Toronto 



gatta, Quincy, Mass. 28. Eastern. 21ft. Class, Marbleh'd 



6 American, Ann., Milton Point. 28. Quincy, Ladies' Day, Quincy. 



6. Winthrop, 3d and 4th Classes, Mass, 



Winthrop. 29. Beverly, 21ft. Class, Marbleh'd 



7. Winthrop, Moonlight Sail. 30. Hull, Classes 3, 4, 5, Hull. 

 7. Fall River, Ladies' Day, Fall R 30. Dorchester, Dorchester. 



7. Miramichi, Cup, Chatham. 30. Indian Harbor, Ann., Green- 

 9. Riverside, Ann., Riverside. wich. 



9. Hull, Classes 1, 2, Hull. 30. Corinthian, Marblehead. 



9. Monatiquot, Open., Ft. Point. 30. Savin Hill, 2d Chum. 



9. Sipoican. 1st Open Sw., Marion 30. Mos. Fleet, Open, Boston. 



9. Buffalo, Laoies' Day. 

 10. Savin Hill, Cash Prize. 

 15. L.Y'.R.A., Belleville, Ont. 



30. Beverly, Monument Beach. 

 30. Buffalo, Cruising, Sweeps. 



AUGUST. 



16. Winthrop, Cash. Winthrop. 



17. Hull. Ladies' Day, Hull. 



19. Winthrop, 3d and 4th Classes, 

 Winthrop. 



20. Corinthian, Marblehead. 



3. Hull, Open. Hull. 



5. Winthrop, Moonlight Sail. 



5 Corinthian, Atlantic City. 



6. Douglaston, Ladies'Day.Little 



Neck Bay. 



6. Sippican, 2d Open Sw.. Marion 20. Beverly, Monument Beach. 



6 Cape Cod, Town Cove. 20. Hull Cor., ?d Cham., Hull. 

 6. Corinthian, Marblehead. 20. Cape Cod. Town Cove. 



6. Hull, Classes 1, 2, Hull. 20. Miramichi. Triang., Chatham. 



8. Buffalo, Annual Cruise. 21. Winthrop. Cruise. 



9. Miramichi, Stewart Pen., Black 22. Rhode Island, Open. 



Brook. 23. Fall River, Open, Fall River. 



10, Corinthian Mo=quito Fleet. 25. Rochester. Club Regatta. 



11. Rochester, Ladies' Day. 26. Quincy, 3d Cham., Quincy, 

 1 3. Dorchester, Dorchester. Mass. 

 13. Monatiquot, 2d Cham., Ft. Pt. 27. Hull, Cup Race, Hull. 



13. Chelsea. 

 13. Savin Hill, Second Cup. 

 13. Mos. Fleet, Cham., Boston. 

 13 Winthrop, Ladies' Day. 

 13. Cape Cod, Town Cove. 

 13 Quincy, Invitation Race, 



Quincy, Mass. 

 16. Monatiquot, Ladies' Day. 



27. Dorchester, Dorchester. 

 27. Larchmont. Oyster Boats. 

 27. Savin Hill, Sail Off. 

 27. Mos. Fleet, Cham., Boston. 

 27. Winthrop, 2d Class Cham., 



Winthrop. 

 27. Buffalo, Ladies' Day. 

 27. Sippican, Open, Marion. 



SEPTEMBER. 



2. Winthrop, 3d and 4th Classes, 



Winthrop. 



3. Larchmont, Fall, Larchmont. 

 3. Rochester, Autumn Cruise. 

 3. Beverly, Monument Beach. 



3. Buffalo, 2d Pennant. 



4. Hull Cor., Open. Hull. 



5. Corinthian. Marblehead. 

 5. Beverly, Monument Beach. 

 5. Mos. Fleet, Open, Boston. 

 5. N.Y.Y.R.A., Ann., New York. 

 5. Corinthian, Atlantic City. 

 5. Douglaston, Sweeps, Little 



Neck Bay. 



OCTOBER. 



1. Corinthian, Atlantic City. 15. Buffalo, Closing Cruise. 



5. Lynn, Open, Nahant. 

 5. Fall Kiver Club. Fall River. 

 8. Miramichi, Sweep, Newcastle. 

 8. New York, Schooner Sweeps, 



New York. 

 10. Sippican, 3d Sweep, Marion, 

 10. Eastern, Fall, Marblehead. 



14. AVinthrop, Cash, Winthrop. 



15. Rochester, Grand Review, 

 15. Corinthian, Atlantic City. 

 17. Beverly, Monument Beach . 



18. Miramichi, Triang.Neweastle 

 24. Chelsea. 

 24. Buffalo, 3d Pennant. 



A movement is on foot in the Corinthian Navy to abandon the 

 length and sail area rule for a measurement of waterline length 

 alone. One of the members favoring the change is Mr. Clapham, 

 who recently appeared in our columns as a defender of the length 

 rule, afterward expressing his belief in a radically different rule, the 

 old "cubic contents," and finally admitting that he was satisfied with 

 the existing length and sail area rule. It is to be hoped that the 

 other experts of the Corinthian Navy are better posted as to what, 

 they really think and want. 



While we believe in the Seawanhaka rule as applicable to all sizes 

 and classes, it is quite possible that practical difficulties have arisen 

 in its use for a mixed fleet of all rigs and sizes of sailing boats and 

 small yachts. Before abandoning it an this account, it is well to 

 consider that the first requisite in any rule is a uniformity among all 

 clubs; and further, that whatever its faults, it is a much fairer rule 

 than any of its predecessors, such as mean length, waterline length 

 length and beam or cubic contents. 



One uniform rule for all yacht clubs is at this time an imperative 

 necessity, a yacht built one year for racing in the Corinthian Y. C, 

 of Marblehead may next season be sold to Newport, New York or 

 Philadelphia, the Boston and New York boats of the last five years 

 being scattered over the lakes as well as all parts of the coast. If 

 each club and each locality has its own rules, as was once the case, 

 this sale of yachts to new ports must largely cease and the value of 

 ex-racers will decrease in proportion. It would be better on the 

 whole that all clubs should use one poor rule rather than that half a 

 dozen better rules should be in simultaneous use. 



The principle of the length and sail area rule has been thoroughly 

 tested by all the larger yacht clubs of this country and Great 

 Britain, and the rule has been accepted as superior to any other yet 

 proposed. This being the case, such further improvement as is 

 desirable should be iu the direction of the details and the practical 

 application of the rule to the various sizes of yachts and sailing 

 bsats. As for the length rule in an y of its forms, not only the leaders 

 but the great body of yachtsmen have progressed too far, and are 



