Principles of naval engineering - Historic Naval Ships Association

PRINCIPLES OF NAVAL ENGINEERINGerror signaL This signal produces a rapid responsefrom the system when the engineeringplant is in the maneuvering mode. Under normalmode of plant operation the speed feedback signalis not utilized.The signals for astern throttle movement arehandled in the same manner but all of the polaritiesare reversed.In the near future we may see a substantialincrease in the automation of naval propulsionmachinery and auxiliary machinery. At the presenttime, it is entirely possible to design acompletely automated ship. Although completeautomation is an unlikely goal for the naval ship,three is little doubt that automation will increaseto some extent within the next few years.FUEL CONVERSION PROGRAMAs of this writing, the Department of Defensehas authorized the Navy to shift to an all distillatemarine diesel type fuel which will replacethe Navy Special Fuel Oil (NSFO) now in use.The shift will take place on a gradual basis overa three year period. This conversion will easethe principal adverse factors associated with theuse of Navy Special Fuel Oil such as:1. Fouling of firesides of boilers by permissibleimpurities in Navy Special Fuel Oil, principallysulphur, ash, and carbon residue.2. Decrease in ship readiness associatedprincipally with cleaning of firesides.3. High corrosion rate of above-deck equipmentassociated with exposure to products ofcombustion of Navy Special Fuel Oil.4. Substantially below average retention rateof Navy enlisted personnel who perform boilercleaning operations.Testing planned completion date 1975, ispresently taking place with diesel engines andgas turbine propulsion plants; the results of thesetests are to be evaluated for the "Single- Fuel"Navy concept, which will permit the Navy tooperate either steam diesel, or gas turbinedriven propulsion plants with one and the sametype fuel.GENERAL TRENDSIn conclusion, it may be of interest to notesome general trends in naval engineering and tohazard a few predictions concerning possiblefuture developments.we may expect continuing refinementFirst,and improvement of the machinery and equipmentnow in use. The steam turbine, the diesel engine,the gas turbine, thenuclear propulsion plant— allare capable of further development and perhapsincreased efficiency. We may reasonably lookfornew designs in boilers, turbines, reducing gears,bearings, propellers, condensers and other heatexchangers, and a wide variety of auxiliary machinery.Some improvements may be aimed atreducing mechanical losses, others at increasingthe utilization of power developed by the primemover, others at reducing noise levels, and stillothers at minimizing maintenance requirements.We may look forward to the introduction ofnew engineering materials-metals and alloys,plastics, ceramics, lubricants, and others. Wemay watch for— though not necessarily count on—a materials breakthrough that would raise theupper temperature limits of our present machinery.If it is not possible to devise new materialsto withstand ultra-high temperatures, wemay perhaps lookfor new designs that will enableus to utilize higher temperatures with some ofour present materials. We may also expect newand improved techniques for welding or otherwisejoining metals, new methods of metal formingand shaping, new methods of treating metalsto obtain desired properties, and new proceduresfor the nondestructive testing of engineering materials.In the more distant future, perhaps, we mightlook for some entirely new concepts of ship propulsion.In particular, we might expect to seeship and machinery designs tending toward theultimate goal of integrating the prime mover, thepropulsive device, the steering device, and thehull form into one coordinated unit. Designers ofships and propulsion machinery have long lookedwith envy at the fully integrated propulsion systemsof many fish, and a good deal of work hasbeen done in analyzing fish propulsion with a viewto picking up some usable ideas. One approachthat has been suggested is to effect undulation ofa flexible hull by pumping water in a sinusoidalpath through a series of compartments. Stillanother approach utilizes a series of undulatingplates. Although no type of simulated fish propulsionis even close to being operational at present,these approaches should not be dismissedas frivolous or trivial. A great deal has alreadybeen learned through biological and simulationstudies of fish propulsion.Altogether, we may expect the future to bringat least a few surprises, a few practical results652