Editing Remotely operated underwater vehicle (section)

==Classification==
Submersible ROVs are normally classified into categories based on their size, weight, ability or power. Some common ratings are:
*Micro - typically Micro-class ROVs are very small in size and weight. Today's Micro-Class ROVs can weigh less than 3&nbsp;kg. These ROVs are used as an alternative to a diver, specifically in places where a diver might not be able to physically enter such as a sewer, pipeline or small cavity.
*Mini - typically Mini-Class ROVs weigh in around 15&nbsp;kg. Mini-Class ROVs are also used as a diver alternative. One person may be able to transport the complete ROV system out with them on a small boat, deploy it and complete the job without outside help. Some Micro and Mini classes are referred to as "eyeball"-class to differentiate them from ROVs that may be able to perform intervention tasks.
*General - typically less than 5 [[horsepower|HP]] (propulsion); occasionally small three finger manipulators grippers have been installed, such as on the very early RCV 225. These ROVs may be able to carry a [[sonar]] unit and are usually used on light survey applications. Typically the maximum working depth is less than 1,000 metres though one has been developed to go as deep as 7,000 m.
*Inspection Class - these are typically rugged commercial or industrial use observation and data gathering ROVs - typically equipped with live-feed video, still photography, sonar, and other data collection sensors. Inspection Class ROVs can also have manipulator arms for light work and object manipulation.
*Light Workclass - typically less than 50&nbsp;hp (propulsion). These ROVs may be able to carry some manipulators. Their chassis may be made from polymers such as [[polyethylene]] rather than the conventional stainless steel or aluminium alloys. They typically have a maximum working depth less than 2000 m.
*Heavy Workclass - typically less than 220&nbsp;hp (propulsion) with an ability to carry at least two manipulators. They have a working depth up to 3500 m.
*Trenching & Burial - typically more than 200&nbsp;hp (propulsion) and not usually greater than 500&nbsp;hp (while some do exceed that) with an ability to carry a cable laying sled and work at depths up to 6000 m in some cases.

Submersible ROVs may be "free swimming" where they operate neutrally buoyant on a tether directly from the launch ship or platform, or they may be "garaged" where they operate from a heavy submersible "garage" or "tophat" on a tether deployed from the garage which is lowered from the ship or platform. Both techniques have their pros and cons;{{clarify|reason=What are the pros and cons?|date=March 2019}} however very deep work is normally done with a garage.<ref>{{cite web|title=ROV Categories - Summary|url=http://www.rov.org/rov_categories.cfm|website=Remotely Operated Vehicle Committee|access-date=4 June 2016|archive-date=17 September 2016|archive-url=https://web.archive.org/web/20160917162517/http://www.rov.org/rov_categories.cfm|url-status=dead}}</ref>