underwater work
{{Short description|Work done underwater during diving operations}}
Underwater work is work done underwater, generally by divers during diving operations, but includes work done underwater by remotely operated underwater vehicles and crewed submersibles.
Underwater work is the activity required to achieve the purpose of the diving operation additional to the activities required for safe diving in the specific underwater environment of the worksite, including finding and identifying the workplace, and where necessary, making it safe to do the planned work. Some of these activities have a wide range of applications in work suitable for a given diving mode, and are likely to be considered basic skills and learned during professional diver training programmes for the relevant mode. Others are specialist skils and are more likely to be learned on the job or on skills training programmes not directly related to diving.
Occupational diving fields
There are several occupational specialty fields in occupational diving, and the work done in them may overlap.
- {{annotated link|Aquaculture diving}}
- {{annotated link|Aquarium diving}}
- {{annotated link|Combat diving}}
- {{annotated link|Commercial offshore diving|aka=Offshore diving}}
- {{annotated link|Recreational dive guiding |aka=Dive leader}}
- {{annotated link|Diver training}}
- {{annotated link|Hazmat diving}}
- {{annotated link|Media diving}}
- {{annotated link|Nuclear diving}}
- {{annotated link|Pearl diving|aka=Pearl hunting}}
- {{annotated link|Police diving}}
- {{annotated link|Potable water diving}}
- {{annotated link|Public safety diving}}
- {{annotated link|Reconnaissance diving}}
- {{annotated link|Rescue diving}}
- {{annotated link|Salvage diving}}
- {{annotated link|Sewer diving}}
- {{annotated link|Scientific diving}}
- {{annotated link|Seaweed harvesting}}
- {{annotated link|Shellfish harvesting}} (such as abalone, scallops, lobster)
- {{annotated link|Ships husbandry diving}}
- {{annotated link|Sponge diving}}
- {{annotated link|Underwater archaeology}}
- {{annotated link|Underwater construction diving|aka=Civil engineering diving, or "Civils"}}
- {{annotated link|Underwater demolition|aka=clearance diving}}
- {{annotated link|Underwater mineral extraction}}
Work skills commonly used in professional diving occupations
There are several kinds of skill that may be needed in underwater work by occupational divers in various fields, and are often learned during entry level training.
=Underwater searches=
{{main|Underwater searches}}
Underwater searches are procedures to find a known or suspected target object or objects in a specified search area under water. They may be carried out underwater by divers, crewed submersibles, remotely operated underwater vehicles, or autonomous underwater vehicles, or from the surface by other agents, including surface vessels, aircraft and cadaver dogs.
A search method attempts to provide full coverage of the search area. This is greatly influenced by the width of the sweep which largely depends on the method used to detect the target. For divers in conditions of zero visibility this is as far as the diver can feel with his hands while proceeding along the pattern. When visibility is better, it depends on the distance at which the target can be seen from the pattern, or detected by sonar or magnetic field anomalies. In all cases the search pattern should completely cover the search area without excessive redundancy or missed areas. Overlap is needed to compensate for inaccuracy and sensor error, and may be necessary to avoid gaps in some patterns.
- Diver searches:
- {{annotated link|Circular search}}
- {{annotated link|Pendulum search}}
- {{annotated link|Jackstay search}}
- {{annotated link|Snag-line search}}
- {{annotated link|Compass search}}
- Spiral box search
- Compass grid search
- Ladder search
- Swim-line search
- {{annotated link|Directed search}}
- {{annotated link|Towed search}}
- Searches using hand held submersible sonar transponders
- {{annotated link|Current drift search}}
- {{annotated link|Depth contour search}}
- Searches by submersibles, remotely operated vehicles and autonomous underwater vehicles
- Searches by surface vessels
- Searches by aircraft
- Searches from the shore
=Rigging and lifting=
{{See also|Rigging (material handling)}}
Most underwater rigging uses equipment and techniques common to rigging in other environments, except for the common use of buoyant lifting underwater, and the equipment designed and used specifically for that purpose.
- Basic ropework, knots and splices, tackle
- Rigging slings cargo nets and spreaders, lifting hooks and shackles
- Lifting bags (variable buoyancy lifting equipment)
- Chain blocks, tirfors and pullers
=Inspection, measuring and recording=
- {{annotated link|Underwater photography}}
- {{annotated link|Underwater videography}}
- {{annotated link|Tape measure#In surveying|Surveyor's measuring tape}}
- {{annotated link|Vernier calipers}}
- {{annotated link|Spirit level}}
- {{annotated link|Clinometer}}
- {{annotated link|Compass}}
=Use of basic hand tools=
- Hacksaws
- Hammers
- Cold chisels
- Pliers
- levers, wedges and crowbars
- Screwdrivers and wrenches
- Pipecutters and bolt cutters
Underwater inspection
Inspection of underwater structures, installations, and sites is a common diving activity, applicable to planning, installation, and maintenance phases, but the required skills are often specific to the application. Much use is made of video and still photographic evidence, and live video to allow direction of the inspection work by the supervisor and topside specialists. Inspections may also involve surface preparation, often by cleaning, and non-destructive testing. Tactile inspection may be appropriate where visibility is poor.
{{expand section|date=January 2021}}
Gallery
File:970216-N-3093M-002 Underwater Construction Training.jpg|Underwater construction training
File:Arbeitstaucher bei Industrietaucharbeiten.jpg|Industrial inspection
File:Buceador en hélice.jpg|Inspecting a thruster grating
File:Coral-drilling hg.jpg|Core-drilling coral
File:Buzos con globos de elevación.JPG|Lifting bags
File:Buzos con cemento.jpg|Placing concrete underwater
File:Buzo junto toma de aspiración del buque.jpg|Inspecting an intake grating
File:ROV working on a subsea structure.jpg|ROV working on a subsea structure
File:US Navy 011105-N-3093M-011 Navy deep sea diver.jpg|Salvage work
File:Ultrasonidos.jpg|Ultrasonic testing
File:Inspeccion mediante corrientes.jpg|Non-destructive testing by measuring electrical current
File:US Navy 080624-N-5329L-290 U.S. Army Staff Sergeant David Gills, assigned to the 86th Engineering Dive Team, attaches a line on a wire rope that is attached to the sunken former Soviet submarine Juliett 484.jpg|Rigging
File:US Navy 051206-N-0879R-005 A U.S. Navy diver uses a scrubber to clean the hull of the Los Angeles-class fast attack submarine USS Key West (SSN 722).jpg|Hull scrubbing
File:US Navy 080724-N-3093M-019 Senior Chief Diver Billy Gilbert, assigned to Mobile Diving and Salvage Unit (MDSU) 2, uses a pipe wrench to remove a damaged propeller on a small patrol boat.jpg|Removing a small propeller
File:US Navy 110520-N-VF350-023 Navy Diver 2nd Class Joshua Westman sucks sand off the bottom of the ocean during a Joint POW-MIA Accounting Command (JP.jpg|Removing sediment with a suction pump
File:US Navy 110608-N-XD935-079 Navy Diver 2nd Class Justin McMillen holds the lift line as Ordinary Seaman Romando Thomas fills air into a lift bag.jpg|Filling a lift bag
References
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{{Underwater diving|prodiv}}