Page 20 - The ROV Manual - A User Guide for Remotely Operated Vehicles 2nd edition
P. 20

  8 CHAPTER 1 The ROV Business
 Table 1.1 ROV Classifications
 Classification General Capability
OCROV MSROV WCROV
Flying eyeball with limited intervention
Full gigabit data throughput with light intervention Full gigabit data throughput with heavy intervention
    Table 1.2 Representative Vehicle Characteristics
 Size Input Vehicle Telemetry Depth Category Power Power Type Rating
 Launch Method
 TMS Thruster/ Tooling Tooling Fluid Flow
OCROV MSROV
WCROV
110/220 VAC 1Φ
440/480 VAC 3Φ
440/480 VAC 3Φ
Low-voltage DC
Medium- voltage DC or AC High-voltage AC
Copper only
Copper or fiber
Fiber only
1/2 300 m Hand (1000 ft) deploy
.1000 m Crane or (3000 ft) A-frame
.3000 m A-frame (10,000 ft.)
No Optional
Yes
Electric/ electric
Electric/ hydraulic
Hydraulic/ hydraulic
Electric only
15 lpm (4 gpm)
70 lpm (18 gpm)
   worldwide population of WCROVs is hydraulic due to the power requirement and the inherent reli- ability of hydraulic systems over their electric counterparts within the seawater environment. OCROVs are generally called “flying eyeballs” as their main job is to function as a shallow water video platform. The MSROV has additional deepwater capabilities along with fiber optic telemetry for full gigabit sensor throughput. The WCROV possesses all of the attributes of both the OCROV and the MSROV along with high-powered hydraulic manipulators and tooling capabilities (Table 1.1).
Table 1.2 depicts representative vehicle configurations and power/telemetry requirements. Configurations vary within each category from vehicle to vehicle, but these represent the general characteristics of vehicles within the specified size category. For specific vehicle parameters, please consult the vehicle manufacturer’s technical specifications.
1.1.3 Vehicle shape versus mission
The length to width (termed “aspect”) ratio of the vehicle directly affects its hydrodynamics. Long slender vehicles generally have lower drag characteristics at higher speeds but exhibit poor station- holding capabilities. Short vehicles have much better station-keeping capabilities along with higher maneuverability in all three axes of travel (x/y/z) but have much higher drag profiles as the speed ramps up. AUVs typically exhibit the classical torpedo shape with a high aspect ratio and minimal number of thrusters coupled with control fins for long-distance travel at higher speeds. The ROV is typically used in station-keeping (or slow speed observation) tasks for close inspection and/or sen- sor and tooling delivery.
AUVs typically have a closed frame for uninterrupted fluid flow about the vehicle (for minimal drag at higher speeds) while ROVs typically have an open frame to allow for fluid flow through the frame due to a higher number of internally mounted thrusters.































































   18   19   20   21   22