Page 332 - The ROV Manual - A User Guide for Remotely Operated Vehicles 2nd edition

324 CHAPTER 12 Sensor Theory
12.3 Common ROV sensors
Although sensor technology is a large and growing field, the majority of ROV-deployed sensors
falls easily into just a few types based upon the job function being performed.
12.3.1 Sensor by job type
“It’s not about the vehicle, it’s about the sensors and tooling” (Phil Montgomery, NAVSEA ca. 2001).
The ROV is simply the “ride to the job site” for most sensors. The choice of sensor will cer- tainly evolve around the client’s final deliverable product from the operation. The decision to pur- chase or lease a particular sensor will be a combination of economics (return on investment) and logistics (opportunity cost for not having the sensor or backup available in the field should you need it). The following are just a few applications requiring sensors. The ultimate sensor selection will rest with the end user of the data gathered during the field operation.
12.3.2 Aquaculture
Aquaculture operations are directed toward the growth of aquatic species for animal or human use (either for direct consumption or use of the products from harvest). The objective is to make the environment as friendly to breeding as economically possible. That means enhancing the “stock- friendly” factors and mitigating the “stock-unfriendly” factors. Examples of stock-friendly environ- mental factors include high dissolved oxygen, optimal breeding temperatures for the species culti- vated, proper pH balance, low parasite and disease content, and other things that will enhance cultivation. Mitigation of stock-unfriendly factors would include net protection from stock natural predators, disease inhibitors, feeding cycle recognition, and water chemistry analysis.
A sample sensor load-out of an aquaculture vehicle would include:
• Dissolved O2 meter
• Alkalinity and pH sensor
• CTD for temperature and salinity measurement by depth
• ORP (oxidation reduction potential)
• Rhodamine
• Turbidity
• Chlorophyll
12.3.3 Construction
The main sensor requirements for subsea construction projects involve dissemination of the physi- cal characteristics of the subsea environment at the construction site along with conditions for com- pletion of the work scope. Such job tasks involve setting subsea structures, measuring distance offset between items (termed “metrology”) for physical connections, placing anchors for proper mooring of large floating structures, and a host of other tasks. Metrology is defined by the International Bureau of Weights and Measures (BIPM) as “the science of measurement, embracing