Ship Systems Engineering Station Research Articles

The Evolution of Machinery Control Systems Support At the Naval Ship Systems Engineering Station

Introduction Machinery Control Systems (MCS) have evolved rapidly with the development of smaller and more powerful computational and display technologies. Over the past three decades machinery controls have moved from hardware-based logic to software-based logic. The use of relays, push buttons and light-bulbs has been replaced by processors, graphical user interfaces, keyboards and track balls. Suppliers have also evolved from using basic circuit cards and military-specified processors running machine language to Commercial Off The Shelf (COTS) processors running high level languages like C11 and JAVA. Networks provide communication using industry standard protocols. These changes have driven changes in acquisition philosophy, life cycle support, training, and modernization programs.

Design, Manufacturing, and Testing of an Improved Watertight Door for Surface Ships

Designed in the 1950s to be watertight during flooding and airtight under normal operating conditions, the Navy standard watertight door for surface ships is inexpensive to manufacture but expensive to properly install and maintain. Furthermore, by today's requirements, it is too heavy. The need for a lightweight, affordable, low maintenance watertight door led to a collaborative project involving the Applied Research Laboratory at Penn State University, Naval Surface Warfare Center, Carderock Division, Ship Systems Engineering Station, and Northrop Grumman Corporation Newport News to design, fabricate, and test an improved watertight door for surface ships. The design and manufacturing of this door is entirely new and based on advances in laser cutting and welding technology. Its novel design reduces the number of dogs (latches) and linkages of the Navy standard watertight door, decreasing the weight of the complete door assembly from 290 to 213 lbs. The door is fabricated from corrosion resistant stainless steel, and its opening and closing forces are extremely low, reducing the potential for mechanical and gasket wear. Pending successful completion of certification testing and with technical warrant holder approval, the new door will offer an attractive choice for insertion by Acquisition Program Managers and Fleet Maintenance Managers.

Engineered Approach to Effective Maintenance Management

ABSTRACTThe Assessment of Equipment Condition (AEC) Program at the Naval Ship Systems Engineering Station has been providing shore based support to assess the condition of shipboard equipment. This paper examines some of the limitations of the existing process. The paper offers an engineered approach to provide condition assessment on board ship and the shore side support necessary to maximize the effectiveness of the total ship maintenance process. The recommended approach uses existing technology and current hardware and software applications. Included in the approach is the use of microcomputer machinery work stations with expert system software, and a central Condition Maintenance Information System with the capability to provide work packages based on condition assessment and to trend the effectiveness of maintenance decisions. The paper identifies a phased implementation with a limited pilot program prior to fleet wide involvement.

New Technology in Oil Content Monitors

ABSTRACTInternational antipollution requirements have been legislated to regulate the oil content of bilge effluent from ships. In response to these standards, the U.S. Navy is currently in the process of installing pollution abatement equipment on all vessels. The equipment will consist of an oil‐water separator in the bilge discharge line, followed by an oil content monitor which makes the final decision on whether or not the water is clean enough to be pumped overboard. The monitor is required to make a real‐time measurement of oil concentration in the range 15 ± 5 to 100 ± 20 ppm for flow rates up to 50 gal/min. and possibly in the presence of interfering contaminants, such as rust.This paper presents the results of the current effort to develop a monitor which satisfies all of these requirements and is sufficiently rugged for fleet deployment. The monitor under development employs two fiber optic systems and a small microprocessor. The first optical system measures the concentration of particles in the flow as a function of their sizes, using small angle forward scattering. The second determines what percentage of the particles in the flow are oil, using large angle scattering. The microprocessor takes the data from the two optical systems and calculates the oil concentration in the flow. Since the particle size is measured by the monitor, no sample preparation is required and the monitor may be placed directly in the discharge line where it responds to changes in oil content in less than one second. In addition, this monitor can notify the operator of impending oil‐water separator failure associated with passing large oil particles.A demonstration monitor consisting of the forward scattering unit has been successfully tested at the NavSea oil pollution abatement test facility at the Naval Ship Systems Engineering Station at Philadelphia. The monitor agrees well with chemical means of measuring oil content. Results of this comparison and laboratory test of a prototype instrument that features contaminant discrimination will be presented.

TEST AND EVALUATION OF THE REVERSIBLE CONVERTER COUPLING REVERSE REDUCTION GEAR

ABSTRACTThe Reversible Converter Coupling (RCC), designed and manufactured by Franco Tosi Industrial of Italy, underwent testing at the Naval Ship Systems Engineering Station (NAV‐SSES) Philadelphia, Pa. in March 1984. The Franco Tosi RCC concept can be simply described as a conventional hydraulic coupling (i.e., input or pump rotor driving an output or turbine rotor) with a set of stationary blades that can be inserted between the two rotors to reverse the fluid direction and hence the output rotor direction. The purpose of this testing was to test and evaluate a main propulsion reverse reduction gear concept, using the Franco Tosi RCC, for its compatibility and applicability to gas turbine propulsion machinery configurations, specifically the AOE‐6 class ship. Satisfactory development of a workable and reliable reversing system permits use of a fixed pitch propeller.The RCC models tested were the Original Type “79,” the Type “79” Prototype, the Type “79” Production, the Type “84” Production, and the Type “84A” Production. A series of tests was conducted to verify rotor integrity, determine RCC efficiency, evaluate machinery interface, and to determine the overall characteristics of the RCC design. Testing revealed that the Type “79” Production RCC was the most suitable for application on gas turbine powered main propulsion systems. The Type “79” RCC design was approximately 10 percentage points higher in astern efficiency than the Type “84” design and, although the structural integrity of the Type “84” design was superior to the Type “79” design, the Type “79” Production RCC was satisfactory for its intended use without introducing any operational restrictions.The Naval Sea Systems Command approved the Type “79” Production RCC for the AOE‐6 class ship in April 1986, based on the information acquired during testing.

RELIABILITY OF SHIPBOARD ELEVATORS — THERE IS HOPE FOR IMPROVEMENT

ABSTRACTIn 1980, at the Ship Systems Technical Symposium in Cherry Hill, New Jersey, a paper was presented entitled “Reliability of Shipboard Elevators — Is There Hope for Improvement?” It painted a bleak picture of elevators and their future. The history of Navy cargo/weapons elevator installations does reveal a wide variety of equipment sizes and con figurations developed by numerous vendors working to different performance specifications for each contract. The result has been poor reliability, a proliferation of spare parts requirements, and logistic and maintenance nightmares. To correct this, NAVSEA has initiated various efforts, including a program to develop and test improved, standardized designs. The improvements expected by that program include standard capacities and speeds, lightweight construction and easy removability for maintenance. This is being accomplished through standard drawings and detailed, as opposed to performance, specifications. But the key to the success of this effort is to design and test for reliability, maintainability and safety. This is being accomplished by following NAVSEA Quality Assurance Plan 200, which specifies failure mode, criticality, stress, worst case and sneak circuit analyses.New equipment will be tested and evaluated at the new land based engineering site (LBES) at the Naval Ship Systems Engineering Station (NAVSSES), Philadelphia, Pennsylvania. This site has been designed to test elevator systems and components and simulate shipboard conditions including temperature and humidity. Initially, equipment intended for the new AOE‐6 and AE‐36 classes will be tested. The site will also be able to test cargo and weapons elevator doors and hatches in an aircraft carrier configuration. The site includes a standard hydraulic power unit (HPU) to operate flush deck and in‐trunk hatches and different door types. This paper describes the philosophy and methods for the overall standard elevator RDT&E effort and how it will improve the reliability of shipboard cargo and weapons elevators.

SHIP SYSTEMS TEST PROCESS —CONCEPT AND APPLICATION

ABSTRACTSome technical managers are moving closer to a more disciplined approach when introducing ship systems into the fleet. In the past, many installed systems with inadequate testing. These systems were simply not operationally ready. The consequences of their actions show in impaired performance, system down‐time and fleet casualty reports (CASREPS).Thorough, cohesive and well‐managed testing will insure operationally ready ship systems. However, testing must not be done as an independent project to prove whether or not a system meets requirements. The technical manager must consider testing as an integral process of engineering and design. He can do this, if he uses the disciplined total systems approach to ship systems' development and introduction. Testing is an important process in this approach; is not an end unto itself; and is integral to the life cycle of a system. The test process must be adequately designed, constructed and operated. Program mangement is the most adaptable management technique to testing. In a test program, facilities, fuel and manpower are significant cost factors. The technical manager can minimize test costs and still use a facility that adequately meets his needs. He should use test sites, test facilities, land based test sites, or land based engineering facilities. He must be creative and innovative. He must introduce other techniques to reduce time and cost. These are discussed.In 1978–1979, one of the authors developed this concept and with the other implemented it at the Naval Ship Systems Engineering Station (NAVSSES), Philadelphia, Pennsylvania. NAVSSES is discussed as the Navy's Ship System Development and Production Test Center. Several system based facilities are introduced.Simply hypothesizing that developmental and initial phase production testing pays off is one thing, but the proof is in actual test results. The paper looks at various tests recently conducted at NAVSSES and shows how several technical managers achieved improved system and component performance through well planned testing, viz., the LSD‐41 propulsion system, the FFG‐7 diesel generator, air compressor, the RACER, and the reverse reduction gear test processes. The phased development of the DDG‐58 LBEF is discussed.The paper concludes that substantial pay‐off resulted in those instances where the technical manager treated testing as a process integral to engineering and design. Other conclusions are also drawn.