Snow Crab Tracking Using Wave Gliders

New Technology Bringing Science and Industry Together
Coastal communities around the globe are seeking better ways to understand and manage regional ecosystems. They depend on the ocean to sustain economic opportunities, ensure food security and safeguard fragile environments and species. For harvesters, scientists and government organisations in Nova Scotia, Canada, timely, accurate and comprehensive data on movements of valued species as crab is essential for designing effective fishery management regimes. Ocean Tracking Network (OTN), the Canadian government and local harvesters have been tagging and monitoring aquatic animals for years. But not all tracking methods are practical or cost-effective for highly mobile, yet slow moving animals like snow... (read more)
2017-06-19 01:57:59

Seeking a Rift

Confused by Fracture Zones
In 1953, Hans Pettersson published Westward Ho with the Albatross, a popular account of his around-the-world scientific cruise on the Swedish sailing ship Albatross. In it he stated, “… geological evidence found in the last thirty years indicates that the Ridge is probably built up by extensive submarine volcanic action, i.e. by molten magma from deeper layers in the crust being extruded through an enormously long fissure in the bed of the Atlantic.” Although Pettersson and earlier authors certainly came close to describing the concept of a rift, it was not until the late 1950s that a rift and rift... (read more)
2014-12-15 02:06:18

Ice Navigation and the ­Electronic Age

Still No Perfect Electronic Solution to the Challenges of Ice Navigation
Ice navigation is more of an art than a science, and like most arts, does not fit neatly into any scheme for enhancement by electronic means. It is an art learned in theory at navigation school, and perfected by many years of practical experience in forcing ships though ice. The successful ice-navigator is living proof that the human brain processes data faster, and with more accurate results for correct decision-making, than any computer currently in service. Thus, it becomes clear that electronic assistance to the process will consist mainly of the provision of tools, which will not only make the... (read more)
2013-01-18 02:19:55

Meet the Hydro International Team at Oceanology International (A-F)

In the third week of March, the entire marine world will be gathering in London, as this is where the biannual Oceanology International event is taking place. The exhibition and the conference bring together technological and scientific developments. With over 550 exhibitors and a state of the art conference programme OI12 is definitely the place to be. OI12 will be held from 13 to 15 March at the ExCel Exhibition and Conference Centre in London’s Docklands. The organisers are expecting at least 7,000 visitors to attend. Hydro international will of course be present. We not only have a stand (No.... (read more)
2012-03-08 09:56:00

Grounding of the Queen Elizabeth 2 (response)

The Rest of the Story
Last month we brought you the story of the famous Cunard cruise liner Queen Elizabeth 2 (QE2), which grounded on 7 August 1992 off the coast of Martha’s Vineyard and the state of Rhode Island. Captain Lusk stated that the US judicial system arrived at the wrong decision regarding who was at fault for the QE2 grounding and suggested that the US agency for this survey, the US Coast and Geodetic Survey, predecessor to the National Oceanic and Atmospheric Administration (NOAA), should have investigated and determined the shoal depth. On this page we give NOAA the opportunity to respond to... (read more)
2009-06-26 12:00:00

The Rocknes Casualty 2004

A Chartmaker’s Retrospect
The MV Rocknes (about 17,000 GRT (Gross Register Tons), draught approximately 10.5m, see Figure 1), en route from Eikefet, Norway to Emden, Germany, hit a shoal in Vatlestraumen, Norway on 19 January 2004. The vessel carried a pilot from the Norwegian Coastal Administration (NCA). Soon after the grounding the ship capsized with the loss of 18 crew. 12 crew were rescued. Norwegian Hydrographic Service (NHS) was blamed for not publishing its knowledge of a presumed new shoal in the Vatlestraumen. Three subsequent lawsuits were necessary to establish a credible explanation of the accident’s root causes. 10 years after the serious... (read more)
2014-07-17 01:17:21

Heaven Descended to Earth

The Invention of the Fresnel Lens
At the dawn of the nineteenth century, France, like every other nation, regarded shipwrecks as an inevitable downside of maritime life. There were fewer than 20 lighthouses dotting the French coastline, and these were generally limited to its harbours, intended to guide ships into port. The government did not keep any records about the number of ships that went down, but the numbers were clearly in the hundreds every year. Napoleon Bonaparte formed the first national lighthouse organisation, the Commission des Phares, in 1811. This came at the peak of his imperial conquest of Europe, and his decree promised to improve... (read more)
2013-09-06 03:52:43

Hydrographic Surveying in Dense Aquatic Vegetation

Digital signal processing for improved bottom tracking
It can be difficult to detect the true bottom depth beneath dense Submersed Aquatic Vegetation (SAV) using current hydrographic echo sounder systems. High acoustic reflectivity of the vegetation can result in depth declarations within the vegetation canopy. This leads to underestimating bottom depth and overestimating dredging quantities required. This is demonstrated at a harbour, densely colonised with a robust bladed seagrass. Two echo sounder systems were used simultaneously - one a widely used single-beam hydrographic echo sounder; and the other a similar system designed to detect SAV. Dramatically different results are attributed to differing signal processing approaches. This is further... (read more)
2008-01-01 01:00:00

Hydrography in Japan

Interview with D.Sc. Shoichi Oshima of the Japan Hydrographic Association
In spite of modern communications and connections by air, Japan still is for most people from Europe and America, a ‘far away country’. Hydro international is in the fortunate position to have very good contacts in Japan via dr. Shoichi Oshima, who served as Editorial Advisory Board (EAB) member since the start of Hydro international. The term of an EAB member is officially limited to two years and therefore dr. Shoichi Oshima is now leaving the EAB. On the occasion of his withdrawal he agreed to be interviewed and inform readers on some more details of hydrography in Japan. Can... (read more)
2008-01-01 01:00:00

Artefacts in Multi-beam Echosounder Data

This article is about my thesis project, which I did in collaboration with Auke van der Werf at the Dutch Nautical Academy at Terschelling (the Netherlands). The research for the thesis was done at the Dutch Directorate General for Public Works and Water Management (Rijkswaterstaat). This article presents a subset of the thesis. I would like to share the knowledge I gained and the lessons I learnt about lever-arm errors, motion time delays and yaw misalignment, which can result in dynamic motion residuals, also called artefacts or wobbles.<P>   Over the last decade, Rijkswaterstaat (part of the Dutch Ministry of... (read more)
2008-05-30 12:00:00
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