| 词条 | Towboard |
| 释义 |
|name = Towboard |image = Towboard.jpg |alt = |caption = A towboard being used by a NOAA archaeologist to search for shipwrecks in the Papahanaumokuakea Marine National Monument |acronym = |other_names = |uses = Towed diver search or survey |inventor = |manufacturer = |model = |related = Diver propulsion vehicle }} A towboard is a piece of aquatic survey equipment consisting of a board attached to a rope that is towed by a surface vessel. It is used to tow one or more divers underwater at a constant depth to survey bottom features such as coral reefs. The diver may use a scuba set, or if only a snorkel, may remain at the surface, or travel underwater for around two minutes.[1] The towing vessel travels at approximately 1 to 2 miles per hour and may tow two divers, one with a camera pointing down, and other with a camera facing forward. The boat follows a depth contour to keep the towboard over a specific depth. The divers can also maneuver the board to maintain a more precise depth and avoid obstacles. A survey may cover up to nearly 2 miles over a period of around 50 minutes. This type of surveying method is called a towboard survey, towed-diver survey,[2] and the manta tow technique, the latter named after the Manta Board, an oval towboard marketed for recreational use.[3][4] A variant is the SAM or "Single-armed Manta-board". This consists of a small board with a strap to secure and tow the diver by the forearm. This frees the other arm, allowing the diver to take notes on a pad held by the towing arm.[5] The use of a towboard is considered safe for NOAA reef surveys by trained divers at depths where no decompression stops are required (down to approximately 90 feet).[6] Towboards may be equipped with sensors to record the temperature and depth every few seconds and the tow vessel may have a GPS to record position. Position of the diver is approximate and must be calculated from the boat position, heading and towline length.[6][7][8] References1. ^http://www.aims.gov.au/334 2. ^https://data.noaa.gov/dataset/cred-towed-diver-benthic-characterization-survey-at-niihau-main-hawaiian-islands-in-2010 3. ^http://www.unesco.org/csi/pub/source/rs12b.htm 4. ^http://www.aims.gov.au/334 5. ^{{cite web|url=http://spo.nmfs.noaa.gov/mfr562/mfr5623.pdf|title=A Single-armed Manta-board as a New Diver-controlled Planing Board and Its Use for Underwater Surveys|last1=Zimmerman|first1=Kenneth D.|first2=Thomas E|last2=Burton|year=1994|work=Marine Fisheries Review|pages=12 – 16|accessdate=13 June 2016}} 6. ^1 {{cite web|url=http://www.pifsc.noaa.gov/cred/towboard.php|title=NOAA PIFSC - Towboard Diver Surveys|work=noaa.gov}} 7. ^{{cite web|url=http://coralreef.noaa.gov/aboutcorals/facts/coral_towboard.html|title=NOAA's Coral Reef Conservation Program: What is a Towed Diver Survey?|work=noaa.gov}} 8. ^{{cite web|url=http://www.hawaiianatolls.org/video/towboarding.php|title=NWHI: Video: Tow Boarding|work=hawaiianatolls.org}} External links
1 : Diving equipment |
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