Principal Investigator: Barrie Walden Institution: WHOI Proposal #: 0433409
WHOI proposes to design and build a new, state-of-the-art 6500 meter deep submergence research human occupied vehicle (HOV) for the U.S. oceanographic community to replace the DSV Alvin. By providing the capability to routinely access the deep seafloor and conduct observational, sampling and mapping studies, DSV Alvin has, over the past four decades, helped to revolutionize our understanding of seafloor geologic processes and benthic ecosystems, making important discoveries about the biological, chemical and geological processes that shape our planet.
The proposed HOV replacement will be a more robust and technologically advanced deep submergence vehicle, and will still be capable of operating off of the R/V Atlantis with only minor ship modifications. Proposed scientific elements of the design include many cutting edge technologies, such as a variable ballast system to allow for midwater column research, use of new battery systems to increase bottom time and depth capability to reach 95 per cent of the ocean bottom. Implementation of these unique technologies will allow science users enhanced capabilities and expand the suite of oceanographic disciplines that will be able to use a deep submersible for research. ***
The Alvin Upgrade Project: Project Outcomes In 2004, WHOI received funding from NSF to design and build a new, state-of-the-art 6500 m research submersible for the U.S. oceanographic community to replace the HOV Alvin. A contract was awarded to Lockheed Martin for design of this vehicle in 2007. A Preliminary Design Review held in November 2007 revealed cost estimates for construction would be prohibitive. Consequently, in 2008, WHOI proposed that an alternative lower cost, staged approach to upgrade the capabilities of the current Alvin be pursued. In Stage 1, the 4500 m-rated DSV Alvin would be significantly enhanced although it would maintain its 4500 m depth capability. In Stage 2, the changes necessary to extend Alvin’s depth rating to 6500 m would be accomplished. Because the redefined project involved modifying the existing Alvin, and because it was anticipated that costs would be reduced by conducting the project in-house, WHOI proposed to utilize its Alvin Engineering and Operations Group and the Deep Submergence Laboratory to lead this engineering effort. The Final Design Review for the Stage 1 modifications to Alvin was conducted successfully in September 2010. This upgrade consisted of either new design of, or modifications to, a number of major vehicle components, including a new 6500 m personnel sphere with both electrical and fiber optic penetrators; a new electrical system, new 6500 m syntactic foam, and new illumination and high-definition imaging systems. One of the major – and critical – accomplishments of the Alvin upgrade project was the successful construction of the 6,500 m personnel sphere by Southwest Research Institute (Texas). This was the first time that a project involving forging and electron beam welding of large 6A1-4V ELI titanium hemispheres had ever been undertaken in the U.S., and hence the design and fabrication challenges of this "first of its kind" endeavor were extremely high risk. Weighing more than 11,000 pounds and with walls nearly 3 inches thick, the new sphere is larger, with an interior diameter about 6 inches greater than before allowing for better ergonomics. The number of viewports has been increased from three to five, and additional penetrators for both electrical and fiber optic cables were planned. Construction began in 2007 with the forging for two titanium hemispheres that were then electron beam welded together the following year. Fabrication then continued through a series of steps, including welding of window and hatch inserts, post-weld heat treatment, viewport installation, and hatch assembly. The construction project culminated in a successful hydrostatic test at the Northrup Grumman Facility in Annapolis, MD, in June 2012. While construction of the sphere was underway, WHOI engineers created a mockup of the sphere’s interior that not only dealt with improvements in the ergonomics but also the installation and testing of all the instrumentation and wiring. In December 2010, Alvin was completely disassembled. Its titanium frame was sent out for modifications to allow the larger new personnel sphere to be installed, and all other components to be reinstalled were refurbished. Assembly of the vehicle began in September 2012 when the frame was returned to WHOI, and continued until May 2013, when it was loaded on to the R/V Atlantis for departure for the west coast. In the fall 2013, Navy certification trials were conducted off California. On 18 November 2013, Alvin successfully completed a certification dive to a depth of 3729 meters. Lack of deep water and additional cruise time precluded attempting a deeper dive. In January 2014, the Navy certified Alvin for use to 3800 meters water depth, which will support all planned science activities in 2014. Later this year, an additional certification dive will be conducted to achieve a maximum operating depth of 4500 meters as planned for Stage 1 of the upgrade. This project has had significant impact. The Alvin is owned by the U.S. Navy and is considered a one-of-a-kind national asset. It is available for use by the Navy at any time. The project has upgraded Alvin’s capabilities for observations, imaging, sampling, and data collection for all marine disciplines studying the seafloor and water column – geology, geophysics, chemistry, biology, microbiology. The improved capabilities will transform the ways scientists use the vehicle, as well as increase the efficiency of operations. Several engineering student interns have worked on the project, as well as technical and engineering staff who have been cross-trained among other types of deep submergence vehicles, including ROVs and AUVs. This project partially addresses concerns that U.S. deep submergence systems have fallen technologically behind those of other countries, although an increase in depth capability to 6500 m is still an ultimate goal. This upgrade will help maintain U.S. preeminence in oceanographic research. The vehicle is now available to train the next generation of deep-sea scientists through participation of graduate students and post-docs on research cruises.
