Dynamic 17 Vessel

[Oreo Huppe]

Right whales can be very difficult to spot from a boat due to their dark color and lack of a dorsal fin. Poor weather and sea state or low light conditions can make spotting these whales nearly impossible.

NOAA Fisheries announced proposed changes to the North Atlantic right whale (Eubalaena glacialis) vessel speed rule to further reduce the likelihood of mortalities and serious injuries to endangered right whales from vessel collisions. NOAA Fisheries accepted public comment on the proposed rule until October 31, 2022. The public comment period is now closed. Comments are reviewed and generally posted in the order they were received and may be viewed here.

Most vessels 65 feet or longer must travel at 10 knots or less in certain locations (called Seasonal Management Areas) along the U.S. East Coast at certain times of the year. This mandatory regulation reduces the likelihood of deaths and serious injuries to endangered North Atlantic right whales that result from collisions with vessels. Vessels of all sizes can strike a whale, so we encourage vessels less than 65 feet long to help protect right whales by slowing to 10 knots or less within these areas as well.

To monitor compliance with vessel speed regulations, we developed an interactive speed zone dashboard. Users can explore the dashboard to view vessel traffic by speed, season, month, speed zone, and vessel type.

Separate from the federal speed regulations in the Cape Cod Bay SMA, Massachusetts state law requires most vessels less than 65 feet to travel at 10 knots or less in the Cape Cod Bay Vessel Speed Restriction Area from March 1 to April 30. Speed restrictions may be extended by the Massachusetts Division of Marine Fisheries (DMF) if right whales continue to remain present in Cape Cod Bay. Please visit the Massachusetts DMF website for information on state speed restrictions and advisories.

Right Whale Slow Zones and Dynamic Management Areas (DMAs) are voluntary programs NOAA Fisheries uses to notify vessel operators to slow down to avoid right whales. Maintaining speeds of 10 knots or less can help protect right whales from vessel collisions. Under these programs, NOAA Fisheries provides maps and coordinates to vessel operators indicating areas where right whales have been detected. For a period of 15 days after a whale is detected, mariners are encouraged to avoid these areas or reduce speeds to 10 knots or less while transiting through these areas.

NOAA Fisheries establishes DMAs based on visual sightings of three or more right whales within a discrete area. Right Whale Slow Zones are based on both visual and acoustic triggers. They are identical to DMAs when triggered by right whale visual sightings.

All boaters from Maine to Virginia, or interested parties, can sign up for email or text notifications about the latest Right Whale Slow Zones. You can also follow us on Facebook (@NOAAFisheriesNEMA) and Twitter (@NOAAFish_GARFO) for announcements.

You can check for Right Whale Slow Zones on our online right whale sightings map. Or, you can download the free Whale Alert app, which will automatically notify you when you enter one of these areas. Learn more about the slow zones and DMAs declared last year.

For ships weighing 300 gross tons or more, a voluntary seasonal Area To Be Avoided (ATBA) is in effect each year from April 1 to July 31, when right whales face their highest risk of ship strikes in this area.

The North-South lanes of the Traffic Separation Scheme servicing Boston were narrowed from 2 miles to 1.5 miles (consistent with the East-West Boston Traffic Separation Scheme lanes) to reduce vessel collisions with whales.

The Imedos Dynamic Analyzer (IDA) is the third generation of the well-known Dynamic Vessel Analyzer (DVA) and was developed especially for the method of dynamic vessel analysis. As a worldwide unique system for the investigation of the function of smallest vessels and their regulatory mechanisms, it is the only device that allows the investigation of the endothelium of microvessels.

Dynamic vascular analysis is used in more than 20 countries for various scientific questions in almost all medical disciplines. More than 750 publications have been produced, providing a broad scientific basis for the method and making it the gold standard in the increasingly important measurement of endothelial function.

Stimulation or flicker light phase:For functional diagnostics of the MVD, flicker light is used for 20 s during vessel diameter recording (stimulation phase). The green measuring light is interrupted in the change of the image sequence (12.5 Hz), so that a dark image alternately follows an illuminated one. The recording of the vascular response is continuous and in real time.

Dynamic positioning (DP) is a computer-controlled system to automatically maintain a vessel's position and heading by using its own propellers and thrusters. Position reference sensors, combined with wind sensors, motion sensors and gyrocompasses, provide information to the computer pertaining to the vessel's position and the magnitude and direction of environmental forces affecting its position. Examples of vessel types that employ DP include ships and semi-submersible mobile offshore drilling units (MODU), oceanographic research vessels, cable layer ships and cruise ships.

The computer program contains a mathematical model of the vessel that includes information pertaining to the wind and current drag of the vessel and the location of the thrusters. This knowledge, combined with the sensor information, allows the computer to calculate the required steering angle and thruster output for each thruster. This allows operations at sea where mooring or anchoring is not feasible due to deep water, congestion on the sea bottom (pipelines, templates) or other problems.

Dynamic positioning may either be absolute in that the position is locked to a fixed point over the bottom, or relative to a moving object like another ship or an underwater vehicle. One may also position the ship at a favorable angle towards wind, waves and current, called weathervaning.

Dynamic positioning is used by much of the offshore oil industry, for example in the North Sea, Persian Gulf, Gulf of Mexico, West Africa, and off the coast of Brazil. There are currently more than 1800 DP ships.[1]

As part of Project Mohole, in 1961 the drillship Cuss 1 was fitted with four steerable propellers. The Mohole project was attempting to drill to the Moho, which required a solution for deep water drilling. It was possible to keep the ship in position above a well off La Jolla, California, at a depth of 948 meters.

After this, off the coast of Guadalupe, Mexico, five holes were drilled, the deepest at 183 m (601 ft) below the sea floor in 3,500 m (11,700 ft) of water, while maintaining a position within a radius of 180 meters. The ship's position was determined by radar ranging to buoys and sonar ranging from subsea beacons.

Whereas the Cuss 1 was kept in position manually, later in the same year Shell launched the drilling ship Eureka that had an analogue control system interfaced with a taut wire, making it the first true DP ship.[2]

While the first DP ships had analogue controllers and lacked redundancy, since then vast improvements have been made. Besides that, DP nowadays is not only used in the oil industry, but also on various other types of ships. In addition, DP is not limited to maintaining a fixed position any more. One of the possibilities is sailing an exact track, useful for cablelay, pipelay, survey and other tasks.

The costs are falling due to newer and cheaper technologies, and the advantages are becoming more compelling as offshore work enters ever deeper water and the environment (coral) is given more respect. With container operations, crowded ports can be made more efficient by quicker and more accurate berthing techniques. Cruise ship operations benefit from faster berthing and non-anchored "moorings" off beaches or inaccessible ports.

Dynamic positioning is concerned primarily with control of the ship in the horizontal plane, i.e. the translation along the two horizontal axes (surge and sway) and rotation on the vertical axis (yaw).

For most applications, the position reference systems and thrust elements must be carefully considered when designing a DP ship. In particular, for good control of position in adverse weather, the thrust capability of the ship in three axes must be adequate.

Maintaining a fixed position is particularly difficult in polar conditions because ice forces can change rapidly. Ship-borne ice detection and mitigation is not sufficiently developed to predict these forces, but may be preferable to sensors placed by helicopter.[3]

There are several means to determine a ship's position at sea. Most traditional methods used for ships navigation are not accurate enough for some modern requirements. For that reason, several positioning systems have been developed during the past decades. Producers of DP systems are: Marine Technologies LLC, Kongsberg Maritime, Navis Engineering Oy, GE, SIREHNA, Wrtsil (ex L-3), MT-div. Chouest,[check spelling] Rolls-Royce plc, Praxis Automation Technology, Brunvoll AS. The term digital anchor has been used to describe such dynamic positioning systems.[4]. The applications and availability depends on the type of work and water depth. The most common position reference systems (PRS) and position measuring systems (PME) are:

In the beginning PID controllers were used and today are still used in the simpler DP systems. But modern controllers use a mathematical model of the ship that is based on a hydrodynamic and aerodynamic description concerning some of the ship's characteristics such as mass and drag. Of course, this model is not entirely correct. The ship's position and heading are fed into the system and compared with the prediction made by the model. This difference is used to update the model by using Kalman filtering technique. For this reason, the model also has input from the wind sensors and feedback from the thrusters. This method even allows not having input from any PRS for some time, depending on the quality of the model and the weather. This process is known as dead reckoning.

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