69 



the vehicle was deployed through a 4m x 7m (10 by 23 ft) centerwell. The 

 well extends from main deck to keel and is open to the sea and covered over 

 by hydraulically -actuated watertight doors at main-deck level. The forward 

 and after bulkheads of the well are semicylindrical in order to break up 

 wave action when underway. To further dissipate the energy of water in the 

 well, baffle plates are mounted at the well ends, above and below the waterline. 

 A completely enclosed bridge-truss structure straddles the well which has a 

 45t (50 ton) design load-carrying capacity. The carriage, an elevator-like 

 structure riding four vertical guiderails through the well, provides the means 

 for launching and retrieving the towed vehicle. During a towing operation 

 the carriage is locked at keel level and provides the towpoint for the cable 

 streaming the towed vehicle. Upon retrieval, the towed vehicle is nested 

 to the underside of the carriage; both are then hoisted through the well. 

 The carriage is then locked at its uppermost elevation, the well doors are 

 closed, and the vehicle is lowered to rest atop the well doors. The carriage 

 steadies the vehicle and permits launching and retrieving in sea states of 

 5 or more. 



2.4 UNTETHERED VEHICLES 



Technology in this field is best described as emerging. Although the Applied 

 Physics Laboratory (APL) of the University of Washington has, for over 

 a decade, successfully operated the untethered SPURV and UARS vehicles, 

 there are several major technological areas where breakthroughs are required 

 before untethered ROVs can equal the capabilities of their tethered counter- 

 parts. The following discussion describes current developments in this area 

 and the present state-of-the-art. A listing of untethered vehicles and the 

 activities involved with each vehicle is presented in Table 2.7. Appendix F 

 contains descriptions of each vehicle to the extent that dimensional and 

 operational data are available. 



2.4.1 SPURV I & II and UARS 



The APL vehicles are the only untethered vehicles known to be operational 

 in the civil community. A particularly lengthy description of the SPURV 

 vehicles is given in Appendix F since they are the only operational vehicles 

 in this category. 



The SPURV (Self-Propelled Underwater Research Vehicle) has been under 

 development at APL since 1963, and has conducted hundreds of runs, mainly 

 from U.S. Navy AGOR-type ships (Widditsch, 1973). The initial objective 

 was to develop a controllable trajectory vehicle to acquire data on physical 

 properties of the sea, particularly temperature and sound velocity, and for 

 submarine wake investigations. A 3-element transistor array on the vehicle's 

 bow was developed to obtain multiple microstructure data and a fluorometer 

 for dye diffusion and water transport studies has also been developed. There 

 are presently three operational SPURVs: two SPURV I's which are designed 

 for 3,048m (10,000 ft), and one SPURV II for 1,524m (5,000 ft) depth. 

 Oceanographic and vehicle performance data are multiplexed and digitized and 

 taped on a special recorder. Digital-computer data reduction provides a run 

 summary printout and system performance check a short time after a run. Data 



