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Tutorial: Landers, Fundamentals of Free Vehicle Design and Operation

Instructors:

Kevin Hardy, Global Ocean Design, San Diego, CA

Greg MacEachern, Edgetech, Inc., West Wareham, MAJohn Head, Prevco, Fountain Hills, AZLarry Herbst, Earthlight Communications, Pasadena, CA

Overview

Untethered free vehicles are absolutely the most cost-effective way to get to mid-wateror benthic locations. They can carry traps, samplers, and sensors. They can travel toany depth, and remain from short periods of time to multiple years. They can releasewith countdown timers, acoustic command, galvanic time releases, or a preprogrammedevent trigger. Operations may be conducted on smaller charter vessels from ports close

to the site of interest, freeing explorers from the cost and scheduling issues of largeroceanographic ships. Some are small enough to be lifted with one hand from the ocean,but strong enough to journey to the bottom of any ocean trench. Small free vehicles withno HazMat have been flown overnight on passenger aircraft to remote destinations. Thedeepest places in the Atlantic and Pacific are close to American Trust Territories(Puerto Rico and Guam, respectively), simplifying U.S. Customs approval. Free vehiclesmay be integrated into larger bottom platforms, providing the interval return of massdata recorders to the surface, as done with the ATOC Pop-Up Buoy (PUB) design.

Free vehicles complement the other classes of undersea vehicles: Remotely OperatedVehicles (ROVs), gliders, Autonomous Undersea Vehicles (AUVS), mid-water floats,

towed platforms, and manned submersibles. Each has a distinct suite of strengths andweaknesses. Component technologies such as batteries, glass spheres, syntactic,cameras and lights, may be tested on free vehicles prior to installation on the otherclasses of undersea craft. When a free vehicle is deployed as seafloor robotic station,we call refer to it as a lander. Some samplers, such as drop arms with baited traps andsediment samplers, are best used with a lander. Time-lapse photography or stitchedpanoramic views of a site are best done with a lander. Sitting stationary on the seafloor,landers are absolutely quiet, allowing recording of ambient sound fields. Swarmingamphipods and other benthic scavengers are yet to have their sounds recorded. Oceanengineers gain valuable experience and confidence in deployments of free vehicles.New technology can be tested prior to fleet rollout using these robust, cost-effectiveplatforms.

The concept of free vehicles for ocean exploration was first proposed in 1938 in abrilliant paper by Maurice Ewing (Lamont) and Allyn Vine (WHOI), inspired by thebathyscaphe work of Swiss professor Auguste Piccard. Using rubberized float bags ofkerosene for flotation, assorted instruments and animal traps began arriving on theabyssal plains. Ocean trenches were unfathomable in those early days of free vehicles.Later the bags were replaced with soft plastic jugs, finally reaching the ocean trenches

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in the 1970s. The buoyant fluid technique persists into the 21st century, but is beingreplaced by buoyant glass spheres and syntactic foam. Other new materials andcomponents exist today to achieve the mission objectives of arobotic free vehicle. Still,many of those early ideas, like basic seamanship skills, areprofoundly relevant today.Using a SWOT approach (Strengths, Weaknesses, Opportunities, Threats), this tutorial

will walk attendees through defining a free vehicle based on a potential cruise profile. Acruise doesnt start when a team leaves port, but when the work to get there begins. The limitations of the port facility and surface support ship will be considered.Commercial Off-The-Shelf (COTS) sources of components will be shared, permittingend-users the opportunity to intelligently consider the Make-Buy decision, based onfactors of time, cost, and quality.

The course will cover:I. IntroductionII. Vehicle Design

A. General concepts

1. Potential missions2. Applications of single or multiple free vehiclesB. Frame

1. Hydrodynamics, Stability and trim2. Lifting points3. Taglines4. Release mechanisms5. Anchors6. Drop Arms, traps, core samplers7. Failure avoidance analysis

C. Housings

1. Pressure protected, pressure equalized, pressure tolerantD. Flotation1. Fixed, VB, trim

E. Power, Cables and Connectors, intersphere communicationF. Communication, Ship to SubsurfaceG. Sensors and samplers, including imaging systemsH. Design for operation

1. Modularity means flexibility2. Shipping3. Handling at sea, launch and recovery

I. Testing and Sea trialsIII. Prelaunch preparations and Deck operationsIV. Launch

A. Surface launchB. Suspended deploymentC. Repositioning

V. RecoveryA. Communications and trackingB. Surface recovery beacons

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VI. Sample handlingA. PhysicalB. BiologicalC. Data

VII. Charter vessels

A. Selection CriteriaVIII. Ports of operationIX. Cruise Preparation

A. Staying in touch from the fieldX. Shipping

A. Foreign and domesticB. HazMat and ITAR considerations

XI. Tips from the FieldXII. User Group dialog: fostering a creative dynamicXIII. ReferencesXIV. Reprints of selected papers

The lecture will be supplemented with hands-on lab activities in operating an unmannedfree vehicle.

Instructor Bios:

Kevin Hardy, is CTO of Global Ocean Design (San Diego, CA). Hardy retired as aSenior Development Engineer from Scripps Institution of Oceanography/UCSD in June2011 folowing 36 years of service. In November 2011, he was invited to join JamesCamerons Deepsea Challenge Expedition, leading the successful Lander Team thatdesigned and constructed twin ocean trench rated free vehicles, concluding thatassignment in April 2012. With its corporate partners, Global Ocean Design continues tomake the next logical steps in free vehicle component development.

Greg MacEachern, Edgetech, Inc., West Wareham, MA, supported adaptation of theEdgetech BART board and acoustic deck units to Hardys ocean trench free vehicles.The systems performed successfully in the Tasman Sea, New Britain Trench, and boththe Challenger Deep and Sirena Deep of the Mariana Trench. The Edgetech BARTacoustic system has substantial built-in command expandability, including two releasecommands in the base model.

John Head, Prevco, Fountain Hills, AZ, is President of Prevco Subsea LLC, amanufacturer of a standard line of underwater pressure cases.

Larry Herbst, Earthlight Communications, (Pasadena, CA), adapted a high definitionCanon 5D camera for both still and video operation. His experience with digitalphotography, camera controller interfaces, programming, batteries, and mass storagedevices resulted in some of the finest high resolution, color images of the ultra deep seaever made.