ree ee Ll he Composite Design Bsiodving Approved Features of Standard Types Vib, 1s Advocated—Faults of Individual Engines to be Eliminated SSERTING that the word “stand- A ardization”, when taken in connection with marine en- gines, had become greatly abused, W. V. Lang opened an interesting discus- sion on the standardization of marine engines for cargo vessels before the Institute of Marine Engineers of Great Britain at a recent session. He stated it is difficult to define stand- ardization exactly in its present-day sense. He pointed to the proceedings of the Northeast Coast Institution of Shipbuilders and Engineers, at the meeting held in Newcastle, England, recently, as marking “a (great . ad- vance in marine engine construction, in that the old-fashioned ideas of numerous designers were sought to be skillfully focussed upon one type and approved pattern. He said it is a hopeful sign that men at the head ~of world renowned companies, should drop their differences on minor points and try to agree on’ main principles. Simplicity Should Characterize Design In taking up the body of his dis- cussion, he stated in part as follows: A composite design, embracing the best and eliminating the faults in in- dividual engines, should be the object and the outcome of all deliberations. It is to be hoped, and fully expected, that simplicity with ample strength and rigidity will characterize an adopted design; and from the data available in the various existing de- signs there should be no lack—or need of revision—in thickness of cast iron sections or flanges, or of bearing and wearing surfaces, nor of efficient guides; the minimum of vibration to working parts; or of accessibility to all and every part, and ease in over- hauling and adjustment. Bedplates are usually found in two designs: on tank top, or a girder section bolted on a built seating. The former neces- sitates the holding down bolts going through the watertight plating, the latter allows of independent bolting and re-bolting. It is important in any design that the holding down bolts are easily accessible; also that pump facing and jointing bolts are A box section bolted direct easily accessible. Where an unneces- sary depth exists between the tank top and the level of the engine plat- form, it is a pity that such lost space is not better utilized by making the engine room tank deeper, thereby in- creasing water ballast or ie feed capacity. For the purpose of allowances for wear and tear, I have assumed a period of possibly 30 years. We all know “jobs” of near that age which are, broadly speaking, as good as ever, and I personally lost from my superintendence in 1915 by that cow- ardly and insane torpedo attack on commerce a Palmer job of 30 years of age, still. good for years of sea- going. The double ended boilers had the original furnaces without any patches upon them. Sizes of engines might be arranged for by leading engine builders on the basis of indicated horsepower, rising by increases of perhaps 500 horse- power per size, from 1000 to 2500 indicated horsepower, to. suit the standard hulls that may be evolved and which might give, say vaguely for the purpose of the argument, ves- sels of 3500, 5000, 7500 and 10,000 tons deadweight. Such standardized engines might, would, or could have cylinders of equal diameter and cen- ters, similar stroke rising, say by 3 inches per size, and similar disposal of valve chests, etc. It would then become possible—making due allow- ance for individualism in the re- spective builder’s design and_ finish, and attention to details, etc—to have the component parts of such stand- ardized engine sets absolutely iden- tical to length, diameter and gage. So much so, that manufacturing firms could specialize in piston rods, valve spindles, connecting rods, crankshaft pieces, thrust, propeller, etc. A builder in this event could even take the sur- plus or spare parts from another to help forward his own erections, while at the same time a standardization of prices for spares and renewals would keep down unremunerative production and competition. I suggest nothing new in this hypothesis; it is merely carrying into mercantile design on 179 the grand scale what the navy does in types of warships; and that without materially altering general practice, but only consolidating upon output and reducing cost and maintenance. Reliability is everything in a cargo boat engine. Such steamers trade the world over; to such out-of-the- way places as Mauritius, Ocean Island and Iquique, and places where prac- tically no facilities exist for repair. A run of a month or two months is nothing nowadays to. a tramp steamer, and a run of nearly 80 days, without an easement of alteration of the stop valve, can be vouched for by the writer, for a typical east coast job of 2000 indi- cated horsepower. nor the passenger services can beat the work of the ocean tramp steamer where reliability comes in. It is im- portant that this feature should not be weakened in any new design. Equally should a steamer’s time be- tween ports bear a close approxima- tion to calculation, but it is the ship- builder and his designer who are chiefly responsible in this matter, and unless the engine builder is a partner in the modelling, the “best all-round ship” will never be produced. or renewal. Of Much Interest to Owner Speed and fuel consumption are the twin factors that the ship owner is most interested in next to dead- weight. If a ship can transport 8000 tons deadweight a distance of 240 nautical miles (equal to 276 land miles) in 24 hours at an expenditure of 33 tons of coal, he will not com- plain. I have such a vessel in mind. She is 400 x 52 x 26 feet, loaded draft with a block co-efficient of 0.78. ° It may be taken as good practice that the beam of a cargo steamer should not exceed 7% beams to length, and at such a proportion of hull, good ends are obtainable. The vessel that cannot average 240 miles per day to the River Plate and back is too slow for modern needs and_ the A co-efficient hustling times ahead. of 0.76 would be better. As an owner’s man, I cannot too strenuously urge that maintenance, as Neither the navy Bo ree te CRE ree VN Oe ee Pt STR CHE ET