Simplified method of water cooled exhaust system design and performance assessment

The water cooled exhaust systems are not often used onboard ships. Prime goal is to lower temperature of exhaust gas from main propulsion and auxiliary engines to the defined limit. The design of such systems require detailed analysis of propulsion system operational parameters to meet designer expectations. The paper outlines the cooled exhaust system design problems in specific application. The simplified method of evaluation of expected cooling water flow requirements has been developed. Based on marine diesel engines test bench data, the results of short analysis of cooling water demand for two different diesel engines are presented. A simplified engineering approach may be useful for assessment of exhaust gas cooling system performance in commercial application like rescue vessels wet exhaust design or exhaust gas cleaning systems

Application of underwater hydroacoustic navigation system in the research of submerged cables and ROV umbilicals

There is several algorythms known for a computer simulation of tethers used in underwater vehicles. The results of research done for specific conditions are hardly available. Practically, there is a very limited number of data available for comparision of various calculation algorythms. The described profect was directed on comparison of analytical and experimental results of the sumberged cables behaviour subjected to 3-D water flow. Experimental data were obtained in a part during tests of cable models in circular water tank. Real sea condition measurements done at full scale with ROV and underwater towed vehicles were done to compare data from test tank with reality. Sumerged cable cooridnates were obtained using super short baseline u/w navigation system. Forces inducted in the tethers were also measured using spectal measurement methods. The paper describes major problems encountered during use of the ORE LXT u/w navigation system and summarises experience with real underwater systems used in the research

A measurement of 3-D water velocity components during ROV tether simulations in a test tank using hydroacoustic doppler velocimeter

A computer simulation of ROV tethers performance could be done more precisely if velocity field of water flowing around the tether cable is known. The paper describes operation and performance of the doppler acoustic velocimeter ADVlab. A brief outline of the procedures and related problems with determination of 3-D velocity components in the test tank is described