Rheology as a Survey Tool

“We Are Not There Yet”
To reduce the dredging cost many harbour authorities and governmental bodies are seeking for a more suitable and a rheology-related survey tool. The in situ instruments available on the market are based on mechanical, acoustical, optical or radioactive measuring principles. But before one will be able to map the real nautical bottom, we need to understand the influence of the mud properties (micro scale) on a vessel (macro scale). This article gives an overview of the general reaction forces of the mud which definitely play an important role in the vessel behaviour when sailing into it. Without naming any commercial... (read more)
2011-05-17 03:42:46

‘Killer’ AUV Sonar System

In January 2001, C&C Technologies (C&C), a company based in Lafayette (Louisiana, USA), introduced the first commercially successful autonomous underwater vehicle (AUV) to the offshore industry. The AUV’s survey sensor suite, which included an EdgeTech side-scan sonar and sub-bottom profiler, performed well in the Gulf of Mexico and Brazilian offshore environments. However, West Africa proved more challenging – particularly for the sub-bottom profiler. C&C soon began searching for alternative technologies to provide better sub-bottom profiler penetration and higher resolution side-scan sonar imaging.Jim Chance, C&C Technologies (USA) Art Kleiner, EdgeTech (USA)<P> Narrator: Fast forward to the early autumn of 2004… C&C... (read more)
2008-04-02 12:00:00

Assessing the Quality of Soundings

Ensuring that your hydrographic data complies with the latest standards can be difficult, particularly as standards continually change with new advances in technology. Simon Squibb discusses a ‘binning’ technique that may improve data confidence for surveyors and clients. The standards for hydrographic measurements are regularly reviewed to cope with advances in technology and the demand for higher accuracy data, which continually increases. For example, last year the 4th edition of the international standard, IHO S44 (1), was modified by various hydrographic authorities to meet wider application. To aid their surveyors in assessing the quality of data collected, Andrews Survey has... (read more)
2008-01-01 01:00:00

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

Evolving Terminology

From managing property rights in marine space to the marine cadastre
With extended national jurisdiction offshore brought about by the coming into force of the United Nations Convention on Law of the Sea (UNCLOS), new territories have emerged that need to be explored, exploited, protected and shared. The oceans are being subdivided into Territorial Seas, Exclusive Economic Zones and Continental Shelves, each with attendant rights and responsibilities. Effective marine resource management in these vast coastal regions will hopefully be based on a better understanding of the interrelationships between human activities and marine ecosystems than we have had even in the recent past. UNCLOS has provided a legal mechanism whereby a nation... (read more)
2008-01-01 01:00:00

Uncovering the Mysteries of the Oceans

What is Oceanography and How to Become an Oceanographer
This article will dig into the field of Oceanography and the trends and methods developed over the past decades. Did you know that marine species compound more than 80% of the Earth’s biodiversity? Or that seaweed and other sea plants living in the ocean produce around 50% of the oxygen in the atmosphere? With this in mind, many efforts are now concentrated on studies of the ocean, such as identification of those beneficial to ocean resources and organisms that can be used as medicines for many critical ailments. Within this article, you will also get familiar with terms like biomimicry,... (read more)
2019-02-26 09:44:32

Motion Sensor Performance

Direct Comparison Using 2005 Common Dataset
Integral components of a swathe bathymetry system are the motion and heading sensors. The current trend is to offer a system that combines both components in one package, either as an aided inertial sensor or as two sensors linked by component software. The quality of these inertial sensors has a direct effect on the quality of the final survey. This paper compares five leading available sensors, concluding that they produce markedly differing results. Most surveyors when purchasing or specifying a particular inertial system for a project will base their decision on information generated by the manu-facturers, which often shows all... (read more)
2008-01-01 01:00:00

Oceanology International 2010 Preview (2)

This is the continuation of the Oceanology International Preview. For companies A - L, see part 1  MacArtney Underwater Technology Group MacArtney will be introducing their newest innovation in multiplexers - the NEXUS MK E electrical multiplexer, which is designed to the same high standards as the fibre optic multiplexer range with the telemetry part of the multiplexer adapted to non-fibre optic cables. Another highlight will be the demonstration of a working active heave compensation winch, the Cormac 3 Stainless Steel winch. It will demonstrate load stability during vessel movement on the sea. MacArtney will show their Focus ROTV, camera... (read more)
2010-03-01 05:03:47

Satellite Derived Bathymetry Migration

From Laboratories to Chart Production Routine
Much has been said about Satellite Derived Bathymetry (SDB), but with the exception of SHOM, which led to the introduction of a number of SDB charts into the French chart series, next to nothing has been implemented within the international hydrographic community. This article aims to update readers as SDB, thanks to new generation satellites and modelling, seeing the light after going through a thirty years’ tunnel. In 2014, detailed tests and analysis conducted by government hydrographers, cartographers and recognised satellite scientists operating for a number of projects initiated by the European Space Agency, the WWF and other stakeholders, were completed,... (read more)
2015-10-12 04:09:41

Discovering the True Nature of the Mid-Atlantic Ridge: Part I

Prior to the mid-19th century, the floor of the world ocean was virtually a clean slate. Nothing was known of the bottom of the deep sea with the exception of a few sporadic soundings. In the early 1850s, this began to change as Matthew Fontaine Maury obtained use of one small ship, the USS Dolphin, and sent it out on two expeditions, one in 1852 under Lieutenant Samuel Philips Lee and the second in 1853 under Lieutenant Otway Berryman. Apparently one sounding of 1,720 fathoms was by Lee southwest of the Azores Islands, but under Berryman a number of relatively... (read more)
2014-09-02 11:50:26
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