184 



FOREST AND STREAM. 



[March 18, 1886. 



my estimation, when I found her 30ft. of length close up on the pair. 

 In course of an hour, when clear of Turkey Point, a bold headland 

 surmounted by a fixed white light, the little cat had run the yacht's 

 lee and conversation was begun. Then I learned with pleasure and 

 some surprise that the yacht hailed fifty milps east of New York on 

 the Sound, and was bound for Florida, for better or for worse. She 

 was a handsome craft. 27ft on deck, of lapstreak build, on the inodpl 

 of the well known Long Island surf boats, but decked fore and aft, 

 with a small cabin in the. stern. Amidships she had hatches, her 

 hold being given up to stowage of provisions in bulk, shooting and 

 fishing implements, etc. She was rigged as a sloop, drew 3ft. aft. had 

 a eenterboard. and was new, neat and trim throughout. Her siding 

 was of %in. cedar, and great care had to be exercised lest the ice cut 

 her through. This yacht had passed through the csnals a few days 

 in advance of the Coot, and had fortunately escaped thecold weather 

 I had experience 1, or it would have fared badly with her light con- 

 struction. For strength she had all the wood arid fastenings required, 

 having but 6ft. beam and no overhang aft. In a general way she 

 might be compared to a ship's "loner boat" with more deadrise and 

 shear. She was a fine sea boat, but loaded too dpep with fittings and 

 stores to profit by the great buoyancv upon which the surf boats 

 depend. Her hatch coamings were low and not watertight, an over- 

 sight which her owner realized and proposed rectifying - some day. 

 The cabin was 7ft. long with a berth on each side, but half the floor 

 space was tak»n up by a gallev stove. Abaft the cabin house, the 

 stern sheets formed a narrow, tiny cockpit, big enough for the man 

 at the helm, and, as I thought, uncomfortably elo*e to the sea, an>l 

 likplv to ship water when the boat heelel, as she easily did. 



Meanwhile the smack had hauled her wind to await our coming, so 

 we might all nvike harbor together for the night. The lookout aloft 

 aided materially in discerning the clear lpads through the field ice 

 which had again packed around us in a threatening manner. We 

 zigzagged through the winding lanes all the afternoon, passing the 

 ic c -ehoked mouth of the Sassafras River, which is three miles and a 

 half across from Grove Point to Howell's Point, a great strpam. up 

 which you can carry 13fr.. to the town of Frederick, ten miles from 

 the capes, and which in places brings up the lead in no less than 8J^ 

 fathoms. Ordinary Point and Turner's Creek, on the south shore 

 opoosite, about tour miles up. afford good shelter. Llovd's Harbor, 

 on the south, two mile* from the mouth, is too shoal, averaging only 

 2%tt. at low water, though it may be entered through a very narrow 

 opening with over 4ft, ou the bar at high tide, if you do not mind 

 taking the bottom at low water inside. 



Below the Sassafras 'he coast tend? southward, forming a big bight 

 to the next headland, after which you open the well known and 

 much frequented Still Pond Harbor. This consists of an outer an- 

 chorage, an indentation one mile deep and broad, tapering at the 

 head where it. splits into two small arms at Kmnaird's Fluff, one 

 called Still Pond proper, with a very narrow and secluded entrance, 

 the other known as Church Creek. Even the outer bay supplies fair 

 anchorage from all but northwesterly winds. It was for this we 

 were making, as it has the reputation of being clear of ice before 

 other shelters. 



The wind had dropped away entirely, while we were still three 

 miles away from our haven. The sky cleared and the weather moder- 

 ated, so our hopes of getting clear of all ice below Pool's Island rose 

 in proportion as we set to at the sweeps and scull with a will. Night 

 overtook us, however, while jammed fast in the pack just before 

 opening the safe retreat. It looked as though we were in for a desper- 

 ate situation, squeezed between some big floes which were carrying us 

 down on the ebb and boded evil in the ruthless scrunching of our 

 boat's sides. I felt seriously alarmed for the safety of my light tim- 

 bered friend, the Long Island surf boat. After exhausting all means 

 to free ourselves we made the best of matters and tossed anchors out 

 ou the floes, lashing all three vessels alongside one another, the surf 

 beat in the middle. Then we cooked supper and awaited events with 

 resignation Gradually drifting down abreast of the bay we dis- 

 covered with concern that it was closed with the ice solid across from 

 shore to shore, but apparently of new formation near the entrance. 

 Hailing in the dark, an answer came from shore with the cheering 

 information that we could not get in. Captain So and So's schooner 

 had been fast for two week3 and could not budge an inch. It would 

 have been madness to remain in the drifting pack as we had tempo- 

 rarily brought up. so an effort had to be made to cut a way into the 

 fast ice and so at least avoid the friction of the moving fields. For 

 four hours, nearly up to midnight, we hacked and smashed and stove 

 away with ovrs, poles, hooks and hatchets, till the heavy floes were 

 cut through and quitted to go on their voyage down the bay alone. 

 Then our friend of the smack sent his son ahead in a stout yawl boat 

 and by dint of violent rocking from side to side, he succeeded in 

 slowly breaking a channel well into the fast ice under the protection 

 of the northernmost bluff of the harbor. We then sculled the boats 

 iato his wake and in the light of a bright moon brought up for rest in 

 tolerable security with congratulations upon our success. Tired out, 

 bunks were speedily sought and sleep indulged till well along next 

 day. 



The flow of ebb and flood and light easterly airs had by that tune, 

 much to our relief, partially cleared the outer waters of the heavy 

 drift and we got under way. No wind stirring, an ash breeze had to 

 be called in. Now if there is anything I hate it is such artificial style 

 of locomotion. The Coot is a heavy thing to scull along and with the 

 lightest breath ahead, she could scarce be made to answer the most 

 assiduous labor at the ten foot sweep. Of course what wind we were 

 vouchsafed had to come out ahead. There was not room to tack 

 ship through the narrow waterways we were working, so our whole 

 reliance had to be placed upon the wooden implements of torture. The 

 smack got out sweeps and pulled ahead. The surf boat likewise rowed 

 and both dropped the Coot with her single hand plying the scull over 

 the stern with the greatest vigor and disgust. Out of our berth we 

 forced our way tediously enough down the coast to Wharton's Point, 

 the northern headland of a snug harbor by the same name, some 

 three miles from the anchorage of the previous night, and after 

 doubling the same, two miles more stared us in the face to the head 

 hefore we could fetch into good shelter. Luckily the creek proved 

 quite clear of ice and in due course of time the boats were propelled 

 far enough in and anchors lPt go near a projecting sand spit, around 

 which we could easily drop into more perfect shelter should it come 

 out hard from the northwest. 



In triumph the skipper of the smack ran a brand new star spangled 

 banner to the masthead and broke out a variagated assortment of 

 brass and wind instruments, a bass drum, kettle drum, triangle and 

 cymbals, upon which he and bis son proceeded to regale the neigh- 

 borhood for miles around with choice melodies, such as "John 

 Brown's Body," "Marching Through Georgia," "Red, White and 

 Blue," winding up with the "Rebel Charge-" m soothing of possibly 

 wounded feelings of ante-bellum birth. Imagine a quiet, peaceful, 

 farming community invaded on a calm forenoon, without warning, 

 with the most terrible din, the banging of a sonorous bass drum, the 

 rolling of a rattling kettle, the clang of cymbals, brassy bugle calls, 

 plaintive strains from a fiddle and piping of fifes, and to top all, waves 

 of df leful harmony from the ever-popular accordeon. upon which the 

 great masters were interpreted with a license to correspond with the 

 liberty of the age. Three vessels in a state of pandemomium, bunting 

 flying, smoke issuing from the galley funnels, bedding and clothing 

 littered about in profusion for an airing, and what else could the 

 sudden exhibition produce upo.i the bucolic mind but the feverish 

 state of excitement anticipatory to the arrival of a circus! The 

 countryside woke up in midwinter. The small boy appeared on the 

 brow of the hills in such numbers as the population could afford, the 

 housewife and the lord of the manor appeared, dogs likewise, and 

 they assisted powerfully with their organs of expression. Cat calls 

 resounded through the woods, and hails, half in earnest, half face- 

 tious rang over the calm waters as our impromptu band from New 

 Jersey rent, the air with their devotions to the muse of the lyre. 

 When the festivities had finally ceased as wind and muscle gave out, 

 the old skipper of the smack kept all hands in a state of roaring 

 laughter with humorous reminiscences from his life, and the son now 

 and then chimed in with a choice morsel equally as good. 



A.n exploration of the creek in yawl boats occupied the remainder 

 of the day The surf boat also unshipped her mast and sawed 2y 2 tt. 

 off tne heel, after which she sailed with a single reef in mainsail, she 

 being oversparred for winter work. The night was calm till day- 

 break, when the chafing of the Coot against the smack's side an- 

 nounced the advent of a breeze from southwest, the sky becoming 

 overcast with fleecy clouds at the same lime. Eignt A. M. saw us 

 under sail, our next rendezvous being Annapolis, twenty-eight miles 

 in a southwesterly direction, with Love Point, eigh eenjniles, due 

 south on the eastern shore as a refuge should the wind head us off 

 as it threatened to do. Our plans, however, came to naught, and the 

 Coot was the only one of the three to fetch into Annapolis roadstead, 

 though not until five days later. . . 



A course could j ist be laid out clear of Wharlon's, when the wind 

 was found with enough westing to make it a dead beat down with a 

 night in the b'iy in prospect. As the moon was near full we v&e sed 

 the word to stick to first intentions and make for Annapolis, below 

 wnich we were sure to escape being frozen in for the season. After 

 a board or two to ch ar Pool's Island, we opened the main waters ol 

 Chesapeake Bay and found ourselves well cleai- of busquehanna ic« 

 at last. The Coot soon had both her friends under her lee. and in the 

 smooth water and smart breeze was worfcing away from them m good 

 snape despite her rough split tered bottom. 



Suddenly the wind lulled, then shifted into W. and came out with 

 vigor For a while all hands kept at it un 'er full sail, the rapidly 

 rising sea tossing the Coot about like a lit'le shell. The breeze nad a 

 sweep of eight miles, coming out of Middle River. It rapidly in- 

 creased to a mild gale, and while the Coot was hove into the wind s 

 eve to haul down a single reef, it piped out from northwest id a full. 



fledged storm, which whistled ani shrieked about my head and lashed 

 the waters into furious seas. The halliards were let ran and the 

 close-reef cringle hauled out at once. Tying the points was a difficult 

 job, as it was scarce possible to get along decks, the way the boat 

 was tossing and rolling in waves which by this time were almost 

 overpowering to so small a craft. While thus engaged the smack 

 drove by to the northward under head of her jib, the mainsail hav- 

 ing been doused in a hurry. She lost all the southings we had effected, 

 and in half an hour bad cut and run out of sight, probably trying for 

 Gunpowder River. The Long Islander had freed sheet and headed 

 before the gale in some trouble with his cauvas. When next I looked 

 for him no traces were to be seen, though I scanned the sea with my 

 glasses for a long while. Presumably he had lowered away all and 

 his tiny spars were lost to vision. He could not undertake to lav up 

 in the heavy sea, I thought, and had concluded to run to leeward and 

 hunt shelter around Love Point on the ea-tern shore. In this, I trust, 

 he was successful, for it howled tremendously out of the northwest 

 for three days following. Of my two companion vessels I have 

 neither seen nor heard anything since, though inquiry was instituted 

 at the ports touched on my way do svn. 



A COMPARISON OF TYPES. 



Editor Forest and Stream: 



Last fall, after reading some numbers of your valuable paper, Mr. 

 Robertson, eur builder, and mvself. designed two yachts to represent 

 two prevailing types, now attracting the attention of yachtsmen, 

 And this winter having seen in that wonderful store of information. 

 "Small Yachts." illustrations of some designs similar to ours, we con- 

 cluded to compare elements. 



Accordingly, from the drawings of two illustrations, those of the 

 Petrel and Madge, I deduced such of the elements, not already given, 

 as I wished to compare with the corresponding elements of our own 

 design. 



With regard to our designs of a cutter, as compared with the Madge, 

 there is nothing novel, further than in our giving some elements not 

 furnished in the book, but which may be of intere-t to some of your 

 readers. And with regard to our sloop as compared with the Petrel, 

 we see how a particular characteristic will cling to a particular type, 

 notwithstanding a great disparity in size. 



Bv observing the distances of the center of buoyancy and the center 

 of gT 'Vity in each, from their respective water lines.it will be seen 

 that these two points are coincident in both vessels, showing that 

 though the sloop may have immense sail-carrying power, at a moder- 

 ate heel it is utterly helpless whpn on her beam, as then it is without 

 a righting couple. While with the cutter, the center of gravity being 

 below the center of buoyancy, the righting power is at a maximum 

 when the vessel is on the beam, though it may be "tender" at small 

 angles of heel. 



We see too, in the comparison of the sloops, the wonderful increase 

 in power, derived from the increase of volume, due to increase of 

 dimensions, when these vary all alike. Thus, the sloop, though only 

 HO per cent, greater iu its lineal dimensions, has more than four times 

 the sail-carrying power (as seen in their righting moments) and more 

 than two times as much power to the foot of wet surface as the 

 Petrel. 



COMPARISON OF DESIGN OF CUTTER WITH MADGE. 



Cutter 

 (Pearson's). Madge. 



Length load waterline, ft 30.8 



Beam at loadline, f t 7.9 



Depth, gunwale to rabbet, ft 7 2 



Displacement, gross tons — 16.81 



Center of gravity of displacement below L.L., ft. . 1.33 



Center of gravity below center buoyancy, ft 1 .57 



Metacentric point above center buoyancy, it 1.33 



Arm of righting couple for a heel of 15°, ft 73 



Area of plain sail, sq. ft 1430. 



Ratio of sail area to square of loadline 90 



Arm of sail area above center of lateral plane, ft.. 24.75 



Sail moment=arm xsail area=sq ft 353i>2. 



Flighting moment in foot lbs , for 15° heel 27485. 



Righiing moment in foot lbs., per sq.ft. wet surface 56.76 



Sail area pr. sq. ft. wet surface, sq. ft 2.92 



Mean obliquity of water-lines forward 8 J .20' 



Coefficient of load water plane area 688 



Coefficient of fineness to bottom of keel 38 



Waterline. in terms of beam, as unity 5.04 



Coefficient of immersed section at midship section, .50 



COMPARISON OF DESIGN OF SLOOP WITH PETREL. 



Sloop 

 (Robertson). Petrel 



9.75 

 7.66 

 7.5 

 16.5 

 2 13 

 1.50 

 1.35 

 .712 

 1290. 

 .83 

 23.65 

 30508. 

 26350. 

 50 29 

 2.46 

 9° 10' 

 .656 

 .33 

 5.19 

 .51 



Beam at loadline, ft. . 



f buoyancy t 





28. 





8 



6.1 



4 6 



17.6 



7.5 



518. 



265. 



26.4 



12.6 



.88 



5 



1.18 



M 



1.50 



.94 



1.51 



.93 



3 4 



1.93 



1.95 



.99 



Righting moment, for 15° heel, ft. lbs 31693. 



Righting moment, for 20° heel, ft. lbs 48850 



Center of effort above center lateral plane, ft .... 24 4 

 Righting moment, ft. lbs., per sq. ft, wet surface.. 66.91 



Coefficient of water plane area 60 



Coefficient of fineness of displacement 32 



Mean obliquity of waterlines 12° 40' 



Loadline, in terms of beam as unity 8.43 



Molded depth, terms of beam as unity .81 



Grand Haven, Mich., March 5. 



8400, 

 11200, 

 16. 

 31.7 

 .67 

 80 

 14° 80' 

 3.50 

 .57 



H. C. Pearsons. 



TRIPLE EXPANSION MARINE ENGINES. 



THE most remarkable and interesting fact in connection with the re- 

 turns of the tonnage of new ships launched last year is the decrease 



i|- un,! tons, whereas the tonnage ot sailing ships amounted to nearly 

 105 0(H) tons: but in 1684 the screw steamers stood at 190,000 tons and 

 the saili tg ships at 68,000 tons; and in 3883 the figures were, respec- 

 tively 316 000 tons and 64,000 tons. From these particulars we see 

 that in 1883 the tonnage of new screw ships was about five times the 

 new sailing tonnage; that in 1884 the screw ships were only three 

 tim»s the sailing ships; and that in 1885 the balance wa3 turned 

 against the screw tonnage which amounted to but little more than 

 two-thirds of the sailing tonnage. In other words, during the short 

 period to which we have referred, the aunual production of sailing 

 tonnage increased 64 per cent., while the p-oduction of sere w tonnage 

 decreased nearly 80 per cent., though the cost of steamships per ton, 



exceeded the sailing tonnage, except iu the years I81O-1 and I880 

 Whatever the causes may be which have led to this second reaction 

 in favor of sailing ships, it is clear from the figures we have given 

 that the reaction is a very decided one, and is of considerable interest 

 to marine engineers, who, if freights continue low, will probably 

 have but little work to do except for ships of war and vesselR in- 

 tended for mail, passenger, and other special services. Therefore, 

 any device which diminishes the working expenses of steamers is of 

 peculiar interest at the present time. 



It is extremely satisfactory that the latest great improvement of 

 the marine engine largely diminishes the consumption of fuel with- 

 out any drawback iu the shape of lessened durabil ty of the engines 

 or boilers We refer to the extension of the ordinary compound 

 engine known as the Triple Expansion Engine, where steam of very 

 high pressure is expanded in three successive stages in three separate 

 cv finders. For those of our readers who may not be acquainted with 

 the customary technical expressions we may say that, in the ordinary 

 compouud engine, the steam from the boiler is admitted into a 

 cylinder known as the high pressure cylinder, and after a certain 

 amount of expansion is allowed to enter another cylinder, known as 

 the low-pressure cylinder, where expansion again takes place, atter 

 which the steam passes to the condenser; but iu the triple expansion 

 engine the steam, after leaving the high-pressure cylinder, and 

 before entering the low-pressure, is passed through an additional 

 cylinder known as the intermediate cylinder, where expansion also 

 takes place. In the ordinary compound engine the steam expands in 

 two successive stages, and in the triple compound in three successive 

 stages In a few instances two intermediate cylinders have been 

 used, and the steam expanded in four stages: these are spoken of as 

 quadruple expansion engines, . , J 



Those engineers who have had the largest experience with the 

 triple expansion engine, agree in claiming an economy of fuel of 20 

 per cent, when compared with ordinary compound engines. Cases 

 may be cited where a saviug of considerably over 20 per cent, has 



I been obtained, and no doubt others may show somewhat less than 

 this; but 20 per cent, is a saving which ship-owners may, as a rule, 

 safely depend upon ae being obtainable by the substitution of triple 

 expansions for the old compound engine. Of course it very much 



1 depends upon the particular compound engine taken as the standard 



of comparison, Taking a good specimen, that is, an economical 

 specimen, with which the consumption of fuel may be taken as 2 lbs. 

 of coal per indicated horse power per hour, on a sea voyage, and 

 taking the average consumption of a triple expansion engine, where 

 the initial pressure is about 140 lbs. above the atmospheric pressure, 

 at l-61bs. per indicated horse power per hour, we have a saviug of 20 

 per cent. When an old compound engine with an initial pressure of 

 OOlbs. or less has been replaced by a triple expansion engine, the sav- 

 ing in fuel has approached 30 per cent. Assuming a saving of 20 per 

 cent., this large reduction is not only a saving of 20 per cent, in the 

 coal bill which the owners have to pay, but, also, for any given voy- 

 age, a reduction of 20 per cent, in the amount of coal to be carried, 

 and to be provided for in the design of ship. The longer the voyage 

 the greater is the absolute saviug, and in China and Australian trades 

 the advantage is very considerable. Not only may the capacity of 

 the coal boxes be diminished, but the size ortbe numberof the boilers 

 may be so reduced as to occupy much less space than the boilers 

 necessary to supply steam for a compound engine. The reductions 

 from these two causes are a gieat advantage, even after allowance 

 has been made for any increase of space which may be necessitated 

 by the engine itself . The triple expansion engine, therefore, offers 

 the ship owner, who is ordering a new s'eamship or refitting an old 

 ship, the prospect of a considerable gain in comparison with recent 

 vessels which have not been supplied wiih this type of engine. 



The advantage obtained by the use of steam ot about 15()lbs. press- 

 ure, expanded till the pressure becomes very low, may theoretically 

 he obtained as fully in the ordinary compound engine as in the new 

 type, but experience has shown that in the former no appreciable 

 gam in economy is cerived by increasing the pressure, over about 

 80lbs. per square inch, and the cause of this appears to be that when 

 a cylinder works through a large range of pressure, and therefore 

 through a large range of temperature the loss of steam by conden- 

 sation more than balances the gain due to the use of the higher 

 pressure. In the triple expansion engine the steam being expanded 

 in three cylinders i" the three successive stages, the range of temper- 

 ature in any one cylinder is much less than the range would be if the 

 expansion were carried out in two stages. This limitation of the 

 temperature through which the cylinder works is not the practical 

 application of any new priuciple, for the ordinary compound engine 

 derives its advantage over the simple engine from the application of 

 the same principle. 



It may be asked, Why. with these advantages of economy of fuel, 

 and compactuess of machinery spaces, was not this principle of 

 generating steam of very high pressure and utilizing it by means of 

 triple expansion brought into general use before now? The answer 

 to this reasonable question is that, although the principle was under- 

 stood, the difficulty of manufacturing suitable marine boilers was 

 insurmountable until the introduction of reliable steel plates capable 

 of withstanding, without impracticable thicknesses, the great 

 strains due to the higher steam pressure. The adoption of this im- 

 proved type of marine engine is following as a consequence of the 

 improvements made in the manufacture of boiler materials. 



The triple expansion engine was first fitted on board the Propon- 

 tis, by Mr. A. C. Kirk, iu the year 1874. This vessel was supplied 

 with boilers on the water tube principle, capable of standing a work- 

 ing pressure of 150lbs., but of ter a time they gave considerable 

 trouble and were removed from the ship. The trials proved that the 

 engine was very economical in the use of steam. The water-tube 

 boilers were replaced by ordinary marine boilers to work at POlbs. 

 pressure— a high pressure at that time -and we believe the engines 

 are still at work. About four years later, a small set of these en- 

 gines were tried in the yacht Isa, and gave satisfaction. The Aber- 

 deen, however, was the first vessel which came into gene - al notice 

 for the economical and satisfactory results attainable on a long 

 sea voyage be means of the triple expansion eugine. The Aberdeen 

 — a ship 350ft, long by 44ft. beam by 33ft, deep — wasbuilt and en 

 gined by Mr. A. C. Kirk's firm in 1881, for the Australian trade, and 

 the particulars of the early trials were published at the meetings of 

 the Institution of Naval Architects in 1882. The results of these 

 trials gave promise of the most satisfactory performance at sea, 

 which promise was fully realized. When at sea, the necessary data 

 were, taken in the most careful manner, and the result was a con- 

 sumption of fuel about 20 per cent, less than that of the best com- 

 pound engines of the same power. Although the particulars of this 

 vessel's performance were published so recently, there are now 

 probably about one hundred sets of the new type of engine at work. 

 The firm which turned out the Aberdeen has supplied triple expan- 

 sion engines to the mercantile marine amounting, in the aggregate, 

 to about 24,000 indicated horse power, and generally considering the 

 short tim e the engine has been before the shipping world as a prac- 

 ticable and economical machine, it has made a remarkable advance 

 in the favor and confidence of shipowners, and, in view of the great 

 advantage its adoption afford3, it will not be surprising to see its ap- 

 plication become rapidly universal in the mercantile marine. Ma- 

 chinery on the new plan is in course of constructien in various parts 

 of the country for the Government, and we understand that for the 

 British Navy, all sea- going vessels, from the largest armor clad to 

 the smallest gun vessel, are for the future to be supplied with triple 

 expansion engioes in preference to the ordinary compound engines, 

 which till recently were in general favor for war purposes. The de- 

 signers of war ships consider it an important feature in their ar- 

 rangements to secure the required horsepower upon as small a 

 weight and space as conveniently, and sometimes inconveniently 

 possible, and their adoption of the triple expansion engine may be 

 accepted as evidence that it offers a decided advantage in the matter 

 of economy of space and weight. Although in the merchant ship 

 economy of fuel is the most importaut consideration, and in the 

 great majority of cases is almost the only consideration, still it is 

 sometimes, in vessels of high speed, necessary to give attention to 

 the question of weight and space, especially when the speed is to be 

 obtained with moderate dimensions of hull. In the largest class of 

 fast vessels, such as the Atlantic liners, t he restriction placed upon 

 the engineer designer, with the space and weight available for the 

 machinery, is not nearly so stringent as in some smaller vessels, but 

 in any future addition to the fleet of these liners a higher speed may 

 be obtained without any increase of the displacement or of the con- 

 sumption of fuel, and we may expect to find that the ''herring 

 pond" will be crossed in less time than the best recorded per- 

 formances. 



We will now make a few observations in general terms about the 

 mechanical arrangements of the triple expansion engine. Where 

 an old compound engine is to be replaced by the new type of engine, 

 the length of engine room is generally so restricted that one of the 

 three cylinders has to be fitted above the others, and the usual plan 

 is to place the high pressure over the intermediate cylinder, and to 

 place the low pressure beside the intermediate, the high nnd inter- 

 mediate cylinders being applied to the same crank, This is the ar- 

 rangement also frequently used in new engines; but a more satisfac- 

 tory method is to place each of the cylinders over a separate crank. 

 The two-crank arrangement tikes up l^ss length of engine room, 

 and is probably cheaper in the matter of first cost, but the three- 

 crank arrangement gives a better balanced engine, with less wear 

 and tear, and a more uniform motion is transmitted to the propeller, 

 which con-equently is more efficient in the propulsion of tne vessel. 

 Experience has proved over and over agalu that the three crank en- 

 gine is more efficient in propulsion than the ordinary two-crank 

 engine. Moreover, when the three cylinders are placed side by side 

 they admit of the internal parts being more easily and rapidly over- 

 hauled than when one of them is below another. The engines of the 

 Aberdeen are of the three.crank type, and the small wear and tear 

 during the four years they have been in use should raise this tvpe in 

 the favor of shipowners. To overcome the difficulty of obtaining a 

 well-balanced triple expansion engine with two cranks, an arrange- 

 ment has been used in a few vessels with four cylinders, two of them 

 over each crank, the high pressure and a low pressure cylinder over 

 one crank, and the intermediate and another low pressure over the 

 other crank. With this plan the low pressure cylinder is divided into 

 two separate cylinders of equal dimensions. This four cylinder en- 

 gine is not likely to be a favorite for triple expansion, but for quad- 

 ruple expansion it is a very suitable arrangement, with the second 

 intermediate cylinder taking the place ot one of the low pressure 

 cylinders. ...... 



'Some little difficulty has been experienced with a few marine 

 boilers working at sea under the high pressures now coming into use, 

 and this difficulty has been erroneously ascribed to the engine. The 

 boilers of the Aberdeen and other vessels have been in constant use 

 on the longest sea voyages, and have given practically no trouble. 

 Experience proves that with proper care, and such care as is not be- 

 yond the capabilities of the ordinary sea-going engineer, and under 

 the conditions wnich obtain at sea, the boilers may be worked at the 

 highest pressures without giving trouble. It is essential that too 

 great a quantity of oil sh >uld not be used in the cylinders, as 

 it passes the condenser and is carried by the feed water into the 

 boilers where with the ordinary scale it forms a deposit which is 

 such a poor conductor of heat that a thickness of one-sixteenth of 

 an inch will sometimes cause over-beating. Of course where over- 

 heating of the plate cakes place, the higher the pressure of steam 

 the more likely is the plate to suffer partial collapse or bulging. If 

 attention be given to this point, and care be taken to regulate the 

 feed and the deusitv of the water in the boiler, no difficulty may be 

 anticipated. In she rt. &e we have already said, with proper care the 

 boilers may be worked on the longest sea voyages without the slight- 

 est trouble. ..... ». 



It is probable that within a measurable period of time the quadru- 

 ple expansion engine will receive more attention than has yet been 

 given to it. With quadruple expansion, steam of higher pressure 

 than that generally used for triple expansion is utilized in the manner 



