who represented a total of 27 tethered, free- swimming ROVs (the military sector 

 was not included) . Only three of the operators responded, but they repre- 

 sented 15 vehicles. The total diving days of these 15 vehicles was 2,007. 

 All of this activity was financed by private industry. In 1978 manned submersibles 

 operated for only 510 dive days. 



1.3 PROBLEMS ENCOUNTERED 



There are many recurring problems that are inherent in the design of the vehicle 

 itself and its application in the field. The most prevalent problem operators 

 have encountered is entanglement of the umbilical cable or the vehicle itself. 

 Entanglement in its most mild form has resulted in merely a short delay until 

 the problem can be worked out. In its more serious form it can lead to abandon- 

 ment of the vehicle for several months until it can be retrieved or its complete 

 loss. Another area where almost half the operators expressed dissatisfaction 

 concerned erratic performance of electrical connectors. Other areas include 

 sediment disturbance which obscures visibility; cable rupture due to drag, 

 stress or abrasion; and electrical interference between the control, power, 

 and data video transmission in the umbilical cable. Less severe problems lay 

 in the area of support ship station-keeping ability, compass performance, power 

 supply surges, currents and sea state limitations. One area of particular 

 importance is the lack of - and need for - qualified experienced personnel. 

 The type of personnel sought varies; but those with an electronics background 

 and experience in undersea operations and shipboard handling techniques are 

 most desired. A listing, by decreasing order of occurrance of problems 

 encountered by free-swimming, tethered ROVs is shown in Table 1.4. 



1.4 CURRENT RESEARCH AND DEVELOPMENT PROGRAMS 



Current research and development in tethered, free-swimming ROV technology is 

 being funded and conducted by a variety of sources; these include the federal 

 governments of several nations and private industrial sources. In several 

 instances the project is funded jointly by the government and industry, with 

 the work being carried out by the industrial partner. (This is particularly 

 true in the United Kingdom. ) 



Most of the ROV research and development programs deal with specific components 

 or aspects of technology. However, the Government of England has embarked on a 

 program which deals with the field in its entirety. The major thrust of the 

 program is to sophisticate the ROV system, increase its efficiency and lessen 

 the hazard to humans by replacing man underwater with a remotely operated 

 system. A tabulation of the current research and development programs by 

 country, task and objectives is contained in Table 1.5. 



1.5 RECOMMENDED RESEARCH AND DEVELOPMENT PROGRAMS 



There are a variety of areas in which present and future ROV capabilities can 

 be improved. For convenience, these are categorized into "immediate" (those 

 programs which enhance present vehicles) and "long-term" (those which call 

 for new developments or further refinements to new techniques) . The programs 

 recommended include developments recommended by operators and manufacturers, 

 and those indicated by trends and potential requirements of the future. The 

 majority of recommended research programs are in support of industrial and 



