ARA Deploys Sonardyne USBL System in Port Survey
ARA Inc. (Sykesville, Maryland) has completed a subsurface survey of Terminal 91 in the Port of Seattle, in which it deployed its ROV ROUMRS and Sonardyne International Ltd.'s (Yateley, England) Scout USBL acoustic positioning system, Sonardyne said last Friday.

Commissioned following the discovery of World War II munitions on the seafloor under the cruise ship facility at Pier 91 within the terminal, ARA’s operation was to identify and clear any magnetic anomalies that could potentially warrant further investigation. The survey was completed in March.

Scout USBL is designed for tracking divers, ROVs and towfish in waters up to 1,000 meters. It calculates the position of a subsea target by measuring its range and bearing from a vessel-mounted transceiver to an acoustic transponder fitted to the target.

To undertake the survey, ARA mobilized its ROV ROUMRS, which was fitted with a Sonardyne WSM 6 transponder. A Scout transceiver was deployed from the side of the dock on a simple pole arrangement. Positioning data from Scout was fed to the accompanying Sonardyne ViewPoint navigation software.

"Although commonly used by the offshore survey and ocean scientific industries, Scout is equally at home tracking a diver or target in just a few meters of water so we were confident that it was the right solution for ARA to use on this unusual project," said Ralph Gall, technical sales manager at Sonardyne in Houston.

Caption: Engineers prepare the ROUMRS ROV, equipped with a WSM 6 transponder, ready for deployment.

Source: Sonardyne International Ltd. press release

Dolphin-Inspired Sonar Could Aid Detection
In Cluttered Environments
Research from the University of Southampton that examines how dolphins might process their sonar signals could provide a new system for man-made sonar to detect targets in bubbly water, such as sea mines.

The researchers used echolocation pulses of a type that dolphins emit, but processed them using nonlinear mathematics instead of the standard way of processing sonar returns. This Biased Pulse Summation Sonar (BiaPSS) reduced the effect of clutter by relying on the variation in click amplitude, such as that which occurs when a dolphin emits a sequence of clicks. The study was published last week in Proceedings of the Royal Society A.

BiaPSS was shown to be effective in distinguishing targets, such as sea mines, from the clutter generated by bubbles in the sonar's field of view, according to the study. The tests used linear frequency-modulated pulses to detect a solid steel sphere that measured 0.12 meters in diameter.

When hunting prey, dolphins have been observed to blow "bubble nets" around schools of fish, which force the fish to cluster together, making them easier for the dolphins to pick off. However, such bubble nets would confound sonar systems because the strong scattering by the bubbles generates clutter in the sonar image, which cannot be distinguished from the true target.

From an engineering perspective, taking a dolphin's sonar and characterizing is not superior to the best existing sonar systems. In blowing bubble nets, dolphins are either blinding their echolocation sense when hunting, or they have a facility absent in man-made sonar. The study examined whether there is a way by which dolphins might process their sonar signals to distinguish between targets and clutter in bubbly water.

"We know that dolphins emit sequences of clicks and the amplitude of each click can vary from one to the next, so that not all the clicks are the same loudness. We asked, what if this variation in amplitude was not coincidental, but instead was key to distinguishing fish from bubbles," said Tim Leighton, lead author of the study and professor at the university. "The variation in amplitude of these clicks is the key: it produces changes in the echoes which can identify the target (fish) in the bubble net, where man-made sonar does not work."

The findings do not conclusively prove that dolphins use nonlinear processing, but show that man-made sonar could differentiate between targets and bubble clutter using dolphin-like sonar pulses, Leighton said.

Professor Leighton added, "There are still questions to answer. For one thing, dolphins would have to use a frequency, when they enter bubbly water, which is sufficiently low that they can hear up to frequencies twice as high in pitch. Until measurements are taken of wild dolphin sonar as they hunt in bubbly water, these questions will remain unanswered. What we have shown is that it is not impossible to distinguish targets in bubbly water using the same sort of pulses that dolphins use."

The authors previously proposed a form of sonar signal, TWIPS, or Twin Inverted Pulse Sonar, which could work in bubble clouds, consisting of pairs of pulses that were identical except that one was inverted with respect to the other. While TWIPS pulses were successful, there was no conclusive evidence that the types of pulses devised for that study are used by any type of dolphin.

Caption: Dolphins in the Atlantic. (Credit: ©chri_spa/Fotolia)

Source: University of Southampton press release

EdgeTech Launches Portable Acoustic Deck Box
EdgeTech (West Wareham, Massachusetts) has designed a new portable acoustic deck box. The Portable Acoustic Command System (PACS) can be used to obtain status information, enable, disable, range-to and release EdgeTech’s low-frequency or medium-frequency acoustic releases and transponders, the company said last week.

Capable of working with all EdgeTech, ORE Offshore and EG&G Marine Instruments acoustic releases, PACS works with acoustic frequencies from 9 to 25 kilohertz. The splash-proof unit operates on internal lithium ion rechargeable batteries and has a backlit screen.

Caption: The Portable Acoustic Command System.

Source: EdgeTech press release

Rapp Hydema Completes Acceptance Tests
For ARRV, Receives WHOI Winch Contract
Rapp Hydema U.S. (Seattle, Washington) deck machinery for the RV Sikuliaq, or Alaskan Regional Research Vessel (ARRV), successfully completed factory acceptance tests in Seattle. The company also announced last week that it was selected by the Woods Hole Oceanographic Institution (WHOI) to supply an electric ROV winch.

Other than winches, the tests for the ARRV deck machinery included the load-handing system, which was tested in an upside-down configuration. All major components have been delivered to Marinette Marine Corp. (Marinette, Wisconsin) since the test, and remaining deliverables will be completed soon. The remaining components from Rapp are two sheaves and a display.

A University-National Oceanographic Laboratory System delegation and representatives of Marinette Marine shipyard and the U.S. Navy's Office of the Chief of Naval Operations witnessed the tests.

The ARRV should launch in October, Rapp said.

The company expects to deliver an electric ROV winch to WHOI in February 2013. It will accommodate 7,350 meters of 0.681 electromechanical cable, or 7,500 meters of 9/16-inch cable.

The winch-powering scheme has three electric motors mounted on the gearbox; management is through variable-frequency drives. Rapp’s Pentagon Research winch control system will provide controls for the active heave compensation. The system could see heavy usage at deployments of up to 7,000 meters of cable, Rapp said.

Caption: A rendering of the Alaska Region Research Vessel (Credit: The Glosten Associates Inc.)

Source: Rapp Hydema U.S.

Proteus Completes Red Sea Satellite-Based
Bathymetric Mapping Project in 10 Days
Proteus (Abu Dhabi, United Arab Emirates) has completed a 200-square-kilometer bathymetric mapping project along the Red Sea coastline in 10 days, deriving the bathymetric data from DigitalGlobe (Arlington, Virginia) WorldView-2 high-resolution, eight-band satellite imagery.

The project could have taken six to eight months if the data had been collected by boat due to required government permits and shallow-water navigation obstacles, Proteus said.

In the Red Sea, the satellite bathymetry process successfully extracted seafloor elevation measurements to depths of 20 meters with a 4-meter point density at distances up to 5 kilometers off the Saudi Arabian Coast.

The project used a bathymetric and seafloor mapping method that Proteus developed in partnership with EOMAP GmbH & Co.KG (Gilching, Germany). The bathymetric data supported an environmental assessment being conducted by Sogreah (Lyon, France) in preparation for construction of a new power plant south of Jeddah, Saudi Arabia.

Source: Proteus press release

Oceans Could Provide 10 Percent
Of Australia's Electricity, CSIRO Finds
Ocean wave energy could play a significant role in Australia's energy sources, provided there is a price on carbon and the specific technology remains within appropriate capital and operating cost thresholds, according to a report published on Wednesday by the Commonwealth Scientific and Industrial Research Organisation (CSIRO).

Ocean renewable energy could supply up to 10 percent of Australia’s electricity by 2050. Compared to wave energy devices, the prospects for large-scale deployment of tidal and ocean energy devices and systems are less likely to penetrate the market before 2050, the report found. Modeling used in the report returned the unexpected result that under all scenarios investigated, tidal and ocean flow energy was not considered competitive in Australia to 2050.

Australia's wave energy resources are concentrated along the country's southern coastline. For example, the total wave energy crossing the 25-meter-depth isobath between Geraldton and the southern tip of Tasmania is more than 1,300 terawatt-hours per year, about five times the country’s total energy requirements. Other factors such as the economics of energy extraction, transmission, environment and social impacts will determine its future exploitation.

The east coast also provides a consistent, albeit not as large, contribution. Tidal energy is most abundant in the Kimberley region in Western Australia and Banks Strait off Tasmania; ocean currents off the east coast of Australia; and ocean thermal energy off the coast of far north Queensland. The report estimates 8 terawatt-hours per year for a King Sound (Kimberley, Western Australia) barrage scheme and 0.13 terawatt-hours per year at most for a Banks Strait tidal stream project. Additional work needs to be done to better quantify the available extractable power from tidal flows.

Nontidal ocean current energy was found to be the least technically and economically viable. However, the potential is large enough—about 44 terawatt-hours per year—to attract commercial interest.

Given the current activity and the outputs of the modeling showing that ocean renewable energy could be a significant contributor to Australia's future energy supply, the study recommends CSIRO commence a structured approach to the development of a renewable energy program.

The study was carried out by the Wealth from Oceans and Energy Transformed flagship programs. The assessment was a first for ocean renewable energy in Australia, CSIRO said.

The full report is available here.

Caption: Australia's coast line in the Southern Ocean has the best wave energy resources. Particular areas to note are the west coast of Tasmania, the southern ocean in Victoria and southwest Western Australia.

Source: CSIRO press release

CARIS Launches Open-Source API
For Making Custom Web Maps
CARIS (Fredericton, Canada) released last week its first open-source API (application programming interface). CARIS OSCAR-js, a JavaScript Map API, allows users to create, embed and display custom Web maps on their website.

The API was created to extend CARIS Spatial Fusion Enterprise and includes tools for navigation, measurement and download, as well as providing a means for developers to create custom tools and extensions. OSCAR-js extends the OpenLayers library and utilizes jQueryUI and YUI user interface libraries, which are used to build CARIS's Spatial Fusion Viewer. Users can create a new client using OSCAR-js and then connect to Spatial Fusion Viewer for centralized site management.

The API is designed around the creation of thematic maps along with optional functionality, such as selection or data download. OSCAR-js supports the use of Open Geospatial Consortium web services.

The source code for the API is available on GitHub under the Apache License 2.0. This will enable the development community to make their own development branches for customization or as a way to contribute code to the project. Building a distribution is done using Maven 3.

Source: CARIS press release