The Challenger Deep is the deepest-known point of the seabed of Earth, with a depth of 10,902–10,929 m (35,768–35,856 ft) by direct measurement from deep-diving submersibles, remotely operated underwater vehicles and benthic landers, and (sometimes) slightly more by sonar bathymetry.
Sonar is a technique that uses sound propagation to navigate, measure distances (ranging), communicate with or detect objects on or under the surface of the water, such as other vessels. Two types of technology share the name "sonar": passive sonar is essentially listening for the sound made by vessels; active sonar is emitting pulses of sounds and listening for echoes. Sonar may be used as a means of acoustic location and of measurement of the echo characteristics of "targets" in the water. Acoustic location in air was used before the introduction of radar. Sonar may also be used for robot navigation, and SODAR is used for atmospheric investigations. The term sonar is also used for the equipment used to generate and receive the sound. The acoustic frequencies used in sonar systems vary from very low (infrasonic) to extremely high (ultrasonic). The study of underwater sound is known as underwater acoustics or hydroacoustics.
A merchant ship, merchant vessel, trading vessel, or merchantman is a watercraft that transports cargo or carries passengers for hire. This is in contrast to pleasure craft, which are used for personal recreation, and naval ships, which are used for military purposes.
The Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research is located in Bremerhaven, Germany, and a member of the Helmholtz Association of German Research Centres. It conducts research in the Arctic, the Antarctic, and the high and mid latitude oceans. Additional research topics are: North Sea research, marine biological monitoring, and technical marine developments. The institute was founded in 1980 and is named after meteorologist, climatologist, and geologist Alfred Wegener.
A research vessel is a ship or boat designed, modified, or equipped to carry out research at sea. Research vessels carry out a number of roles. Some of these roles can be combined into a single vessel but others require a dedicated vessel. Due to the demanding nature of the work, research vessels may be constructed around an icebreaker hull, allowing them to operate in polar waters.
The Marion Dufresne II is a research and supply vessel named in honour of the 18th-century French explorer Marc-Joseph Marion du Fresne launched in 1995 and having two main missions: logistic support for the French Austral Islands and oceanographic research.
Hydroacoustics is the study and application of sound in water. Hydroacoustics, using sonar technology, is most commonly used for monitoring of underwater physical and biological characteristics.
NOAA Ship John N. Cobb was a National Oceanic and Atmospheric Administration research vessel in commission from 1970 to 2008. She was named for John Nathan Cobb and was the oldest commissioned ship in the NOAA fleet when she was decommissioned, having previously served in the United States Department of the Interior′s Fish and Wildlife Service from 1950 to 1956 and in the United States Fish and Wildlife Service′s Bureau of Commercial Fisheries from 1956 to 1970 as US FWS John N. Cobb.
RV Knorr was a research vessel formerly owned by the U.S. Navy and operated by the Woods Hole Oceanographic Institution for the U.S. research community in coordination with and as a part of the University-National Oceanographic Laboratory System (UNOLS) fleet. On March 14, 2016, Knorr was officially transferred to the Mexican Navy and renamed Rio Tecolutla. She was replaced at Woods Hole by the RV Neil Armstrong. Knorr is best known as the ship that supported researchers as they discovered the wreck of the RMS Titanic in 1985. R/V Knorr (AGOR-15) has traveled more than a million miles—the rough equivalent of two round trips to the Moon or forty trips around the Earth. Her sister ship is the RV Melville.
R/V Roger Revelle is a Thomas G. Thompson-class oceanographic research ship operated by Scripps Institution of Oceanography under charter agreement with Office of Naval Research as part of the University-National Oceanographic Laboratory System (UNOLS) fleet. The ship is named after Roger Randall Dougan Revelle, who was essential to the incorporation of Scripps into the University of California San Diego.
R/V Thomas G. Thompson (AGOR-23), an oceanographic research vessel and lead ship of her class, is owned by the United States Office of Naval Research and operated under a bareboat charterparty agreement by the University of Washington as part of the University-National Oceanographic Laboratory System (UNOLS) fleet.
A multibeam echosounder (MBES) is a type of sonar that is used to map the seabed. It emits acoustic waves in a fan shape beneath its transceiver. The time it takes for the sound waves to reflect off the seabed and return to the receiver is used to calculate the water depth. Unlike other sonars and echo sounders, MBES uses beamforming to extract directional information from the returning soundwaves, producing a swath of depth soundings from a single ping.
The AN/UQQ-2 Surveillance Towed Array Sensor System (SURTASS), colloquially referred to as the ship's "Tail", is a towed array sonar system of the United States Navy.
The RV Sonne was a former German fishing trawler converted into a research vessel by Schichau Unterweser AG, doing mostly geoscience-related work for a variety of commercial and scientific clients. She was registered in Bremen. In 2015 she was sold to the Argentine institute CONICET and was renamed ARA Austral (Q-21). A new geoscientific research ship, also called RV Sonne, replaced her role in Germany that same year.
RV Atlantic Explorer is a twin-screw ocean vessel. It is owned and operated by the Bermuda Institute of Ocean Sciences (BIOS) in coordination with and as a part of the University-National Oceanographic Laboratory System (UNOLS) fleet. Atlantic Explorer is in compliance with US Coast Guard, UNOLS and American Bureau of Shipping (ABS) regulations as an uninspected oceanographic research vessel and is supported by the National Science Foundation (NSF). Its homeport is St. George's, Bermuda.
RV Falkor is an oceanographic research vessel operated by the Schmidt Ocean Institute. Ship time aboard the vessel is made freely available to researchers once they have undergone an application, peer review process, and their proposal has been accepted. One condition for using the Falkor is that research findings and data from all expeditions are made publicly available. Researchers aboard Falkor receive expert shipboard support, use of scientific equipment, as well as robotic and computational resources. RV Falkor is adaptable and can facilitate new technologies and external resources as required for each science expedition. Falkor’s current status and a virtual ship tour are publicly available on the Schmidt Ocean Institute website.
The RV Meteor is a multidisciplinary research vessel operating mainly in high seas. She is owned by the German state represented by its Federal Ministry of Education and Research and registered in Hamburg.
RSVNuyina is an icebreaking research and supply vessel intended to support Australian scientific activities and research bases in Antarctica. Capable of deploying a wide range of vehicles, including helicopters, landing barges and amphibious trucks to support the resupply operation, the new ship provides a modern platform for marine science research in both sea ice and open water with a large moon pool for launching and retrieving sampling equipment and remotely operated vehicles.
JS Nichinan (AGS-5105) is the only ship of her type of oceanographic research ship for the Japan Maritime Self-Defense Force.
JDSAkashi(AGS-5101) was an oceanographic research ship of Japan Maritime Self-Defense Force (JMSDF) in the late 1960s.
Germany 
Germany 