Abstract: 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 project 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.