TURTLE – Systems and technologies for Deep Ocean long term presence

Hugo Ferreira3,4, Alfredo Martins4,5, José Miguel Almeida4,5, António Valente6, António Figueiredo1, Batista da Cruz1, Maurício Camilo2, Victor Lobo2, Carlos Pinho4, Augustin Olivier4, Eduardo Silva4,5

1A Silva Matos – Metalomecanica S.A. 2CINAV (Portuguese Navy Research Center)

3ESEIG – School of Industrial Studies and Management, Porto Polytechnic Institute 4INESC TEC - Institute for Systems and Computer Engineering of Porto

5ISEP - School of Engineering, Porto Polytechnic Institute 6PLY Technologies (Engineering)

{hugo.a.ferreira, alfredo.martins, jose.m.almeida, cpinho, aolivier, eduardo.silva}@inesctec.pt, {antonio valente}@ply.pt, {antoniofigueiredo, batistadacruz}@asilvamatos.pt, {mauricio.camilo, sousa.lobo}@marinha.pt

Abstract – This paper describes the TURTLE project that aim to develop sub-systems with the capability of deep-sea long-term presence. Our motivation is to produce new robotic ascend and descend energy efficient technologies to be incorporated in robotic vehicles used by civil and military stakeholders for underwater operations. TURTLE contribute to the sustainable presence and operations in the sea bottom. Long term presence on sea bottom, increased awareness and operation capabilities in underwater sea and in particular on benthic deeps can only be achieved through the use of advanced technologies, leading to automation of operation, reducing operational costs and increasing efficiency of human activity.

I. INTRODUCTION Over the past decades, the underwater operations in deep

sea are an attractive topic in the robotics community. However, most of the work related with deep ocean robotic operations is conducted by a few academic institutions, and the oil and gas industry.

Current operations at full ocean depth are carried out by

dedicated systems and for the most part with the use of ROVs (Remotely Operated Vehicles) operated from a support ship. These systems allow teleoperation on the bottom of the sea and are used in a variety of tasks, from work and assembly in the offshore oil sector to inspection or information retrieval for wide range of activities.

Longer term moored instrumentation is often deployed mainly for information gathering either scientific data collection or defence related information (such as monitoring human activity on the sea for instance by acoustic signal monitoring). In addition, survey and mobile data gathering is performed, not only by surface driven methods such as ships or submerged two-fish systems, but more recently by

Autonomous Underwater Vehicles (AUV). These systems have found increased applications with emphasis on Mine Countermeasures Operations in the military applications or in bathymetric surveying or oceanographic data gathering in civilian oriented tasks.

This project will provide added value by developing new structures, processes and systems allowing higher efficiency in autonomous and semi-autonomous operation on the ocean floor. It will allow for lower transport and reduced logistics for cargo deployment and retrieval (energy efficiency) between surface and ocean floor. This is achieved through the coupling of 3 key elements: new structural lightweight materials for pressure vessel and immersed mechanical structures, versatile and high efficiency methods for surface-bottom transport (taking advantage of variable buoyancy systems and controlled deformable structures) and advanced control and guidance algorithms.

TURTLE aim to develop a robotic benthic lander with

autonomous capability of re-positioning and multiple ascend and descend cycles without the need for human intervention. A benefit is that its efficiency capabilities will allow it to break through the barrier of UUV (Unmanned Underwater Vehicles) long duration missions. Take in account that in nowadays economy people are starting to realize that this new generation of ocean robots can often do what ships do at a fraction of the operation cost.

TURTLE is envisioned to be a system with no need for mooring chains or umbilical cables. Its wireless characteristic is a major benefit in scenarios with crowded surface and subsea systems. High traffic marine waterways or offshore oil and gas industry scenarios with drilling rigs and drilling ships, geological survey vessels, floating production off-loading and storage units (FPSOs), crane and heavy lift vessels, shuttle tankers, cable and pipeline layers, and multipurpose vessels [1]. Underwater operational environments with work-class

operating ROVs, unmanned crawlers, dredging and drilling vehicles, cable laying remote operated vehicles are scenarios were the TURTLE lander prototype cable-free capability is an important asset. Fig. 1 presents a scenario – Deepwater Horizon disaster – were mobility and ship operations were confined to different distance radius.

II. DEEP SEA TECHNOLOGIES - SEAFLOOR LANDERS The oceans bottom are the single largest geographic

feature in our Planet that, not only need to be mapped, but explored. The general rise in resource materials procurement will increase the exploration of deep sea deposits. This will boost the need for marine technologies, with crucial economic and scientific role, for deep sea inspection and exploration tasks.

Deep sea technologies, such as, Remotely Operated Vehicle (ROV) and Autonomous Underwater Vehicle (AUV) systems are utilized, in the oil and gas industry, for underwater surveys, underwater structure/pipeline inspections and construction support, focused in performing repetitive and arduous subsea tasks more efficient and consistent.

A. Manned submersible The deep sea is also visited by manned vehicles capable

of reaching depths of near 11km. A well-knowned project was developed by James Cameron and the National Geographic – the Deepsea Challenger. The manned lander was used in 2012 to go to the deepest place on Earth – the Marianas Trench.

One of the most important vehicles in the oceanographic community is the ALVIN deep submergence vehicle (DSV) from WHOI. A 7 meters length and 16 tons weight submarine that transports a crew of 3 elements till 4500 meters depths for a maximum of nine hours dive.

The French IFREMER institute has the NAUTILE manned submersible capable of 6000 meters depths. The Russian Mir II, battery powered and 3 person submersible, is also capable of achieving 6000 meters depths. This deep diving capabilities allows this vehicles to reach approximately 98% of the ocean floor.

B. Remotely Operated Vehicle The biggest robotic tool for deep sea operations are the

ROVs. Originally conceived as subsea “eyeballs”, ROVs are rapidly evolving into highly capable robotic machines. Work-class ROVs are powerful heavy tools, slow in speed due to the high drag on the vehicle and tether cable, but are dedicated to work via video or imaging sonar on site, with full control of movement along all axes.

Several vehicle are capable of 6000 meters dives: the Tiburon and now the Doc Rickettes from MBARI, Keil6000 from GEOMAR, or Victor6000 from IFREMER. Used within multidisciplinary scientific/industrial projects and for the installation and maintenance of ocean observatories/networks. Equipped with high definition video cameras, fiber optics telemetry, hydraulic thrusters, variable buoyancy system and payload mounting capabilities.

For lower depths (<4000 meters) but with high usability in the scientific/industry community are ROVs, such as,

JASON ROV from WHOI, Quest4000 from MARUM, Venom from SMD, Ventana from MBARI, or the Portuguese LUSO ROV from the Mission Structure for the Extension of the Continental Shelf.

C. Autonomous Underwater Vehicle Numerous worldwide research and development

activities have occurred in underwater robotics, especially in the area of autonomous underwater vehicles (AUVs). This vehicles are commonly used for seafloor mapping, underwater object searching, and pipeline tracking/inspections. Compared to ROVs the AUVs have more autonomous decision capabilities and are un-tethered vehicles, but on the other hand, they have low operational capabilities to physically interact with deep sea structures/platforms.

Vehicles as the Bluefin21 from Bluefin Robotics, which was used in April 2014 for the search of the Malaysian Airline flight MH370, is a torpedo shape with 5 meters and 800 kilograms capable of depth ranges of 4500 meters during 25 hour missions. Similar specifications are demonstrated by the REMUS 6000 AUV which allows 22 hours autonomous operations in up to 6000 meters depths, weighting 800kg and 4 meters long. Kongsberg also develops the Hugin AUV capable of high speed surveys at operating depths of 3000 meters.

Fig. 1 – SENTRY AUV from WHOI close to the Deepwater Horizon disaster site [2]

Nowadays, several non-torpedo shape vehicles have appeared and proven to be design efficient. Normally associated with hovering maneuvers or hybrid ROV/AUV capabilities.

Fig. 1 presents the Sentry AUV from WHOI which is designed to descend to 4500 meters and to carry a range of devices to take samples, readings and pictures from the deep sea.

DEPTHX AUV from Stone Aerospace [3] is an ellipsoid shape vehicle developed for exploration and mapping of deep hydrothermal springs (subterranean cavern) to sub-glacial lake exploration and science missions in Antarctica. Equipped with

several directions sonars that allows it to create 3D maps and implement 3D-SLAM [4].

MARUM Centre for Marine Environment Sciences is developing a hybrid ROV for under-ice operations, near bottom work in harsh topography or hydrothermal vents. It is envisaged a flat shape design with 5x2 meters, capable of hovering maneuvers till 4000 meters depth [5].

The top of the art in deep sea unmanned vehicles was the WHOI hybrid ROV Nereus. It operates in two different modes. For broad-area survey, the vehicle can operate untethered as an autonomous underwater vehicle (AUV) capable of exploring and mapping the sea floor with sonars and cameras. Nereus can be converted at sea to become a remotely operated vehicle (ROV) to enable close-up imaging and sampling [6]. The ROV configuration incorporates a lightweight fiber-optic tether for high-bandwidth, real-time video and data telemetry to the surface enabling high-quality teleoperation. A manipulator, lightweight hydraulic power unit, and sampling instruments are added to provide sampling capabilities [7].

Sadly, HROV Nereus was lost during a dive to 10,000 meters in the Kermadec Trench in May, 2014 [8].

Fig. 2 – HROV NEREUS from WHOI

D. Deepsea Benthic Landers

Benthic landers are instrumented platforms that are lowered and left in the seafloor to gather in situ physical, chemical and biological variables over a period of time. They function autonomously without any connection to the surface for periods of a few days (for biological studies) to several years (for physical oceanography studies) [9], [10].

They can be deployed in a free fall mode or, deployed in a high precision location to measure geomorphological features using special design launching device connected to the surface ship. Normally they are retrieved by an acoustic command that releases ballast weights.

Benthic landers come in a variety of shapes and sizes depending upon the instrumentation they carry, and are typically capable of working at any ocean depth [11], [12].

1) Micro tripod open-frame landers

Open frame tripod shape equipped with high definition cameras for deep sea creatures’ image capture. Other missions incorporate multiparametric water quality sensor probes.

The ROBIO – Robust BIOdiversity lander [13] is a free-fall autonomous baited camera lander rated to 3000 meters and has been used in several biodiversity surveys in the vicinity of sub sea oil extraction. The landers (presented in Fig. 3) carry the camera as well as other equipment which measure how fast the current is moving, and in which direction, and it also measures how salty the sea is (salinity).

Fig. 3 – The entire ROBIO lander with mooring and ballast ready for deployment

The ISIT (Intensified Silicon Intensifier Target) lander has been designed to research spontaneous and stimulated bioluminescence in the water column and benthic boundary layer to depths in excess of 4000m [14].

Fig. 4 –ISIT deep sea lander (left). Medusa modular lander (right).

MYRTLE – Multi-Year Return Tide Level Equipment is a deep water free-fall lander used mainly for measuring sea pressure/depth. It is designed to stay in the seabed for 5 years and gradually release data capsules. The new version is the MYRTLE-X capable of ten years deployments.

The Medusa research lander system is a low cost modular system rated for 2000 meters depth (See figure Fig. 4). Autonomous video and instrumentation lander with high payload capacity, a modular frame, and an acoustically-actuated sacrificial drop-weight release mechanism, allowing recovery from the surface. It can operate in three different modes, as a lander, mooring, or drifter [15].

The WHOI HADAL-lander A and B are free-falling baited landers equipped with high resolution video cameras and conductivity temperature and depth (CTD) sensor.

2) Macro open-frame landers

Longer term deployments and with a greater number of equipment leads to landers growth in size.

DOBO – is the Deep Ocean Benthic Observatory lander from the Aberdeen Ocean Lab. Designed with a titanium structure, capable of 10 month deployments at water depths of 2500 meters. It is fitted with bait release systems and stills cameras in time lapse mode. It released portions of bait at pre-programmed time intervals. The bait will attract fish and invertebrates that are photographed by the lander cameras.

The lander presented in figure Fig. 5 was deployed for gather data on within-canyon water and sediment movement to determine their impact on deep-sea corals and other biota.

Fig. 5 –DOBO deep sea lander (left). Deep sea coral study lander (right).

The German company KUM Kiel develops the K/MT lander. With 2 meters wide and possible titanium structure allows to descend them up to a depth of 6000m and attach a variety of instruments, e. g. benthic chamber, sediment trap, syringe sampler.

Denmark KC-Denmark Company produces several custom made deep sea landers (See figure Fig. 6).

Fig. 6 – K/MT deep sea lander (left). KC-Denmark lander (right).

GEOMAR develops and deploys several underwater landers [16]. Systems like the BIGO lander (autonomous biogeochemical ocean floor observatories) monitor the Baltic Sea floor. The GasQuant lander uses acoustic swath sonars to quantify the volume discharge through bubbles in underwater vents [17].

The BOBO Benthic Boundary Observatory [18] is a 4-m tall deep sea lander from the Netherlands Institute of Sea Research. This landers measure near-bottom temperature, salinity, the amount of particles in the water column, current speeds, current directions, and are equipped with cameras. All data collected by the landers are stored on data disks The BoBo lander will be deployed either as free fall lander (released at the sea surface) or, to get a defined and more accurate positioning, it will be lowered on a wire and dropped approx. 50m above the bottom by using an acoustic releaser.

The Netherlands Institute of Sea Research also uses the ALBEX lander that it is normally deployed in the Middle Atlantic deep-water canyons.

Other line of work are the landers for in situ measurements at the Sediment-Water Interface. Focused on the biogeochemical cycling of organic matter in the seafloor sediments. The SedOBs and NusOBS are two landers deployed to monitor the exchange process between sediments and water in Shelf Seas (coastal areas). AMERIGO is another benthic lander for dissolved flux measurements at sediment-water interface. The lander is able to measure fluxes of nutrients such as ammonium, nitrites, nitrates, phosphates and silica, gases such as oxygen, carbon dioxide and methane, trace elements such as heavy metals and also other dissolved pollutants resulting from human activity.

NOAA (National Oceanic and Atmospheric Administration) uses benthic landers to perform long term monitoring and data gathering in deep-sea habitats. Fig. 7 shows the triangular aluminum frame lander used to study unique slope habitats, such as deep-sea coral reefs and deep canyons.

Fig. 7 – Univ. of North Carolina at Wilmington benthic lander

The ECOGIG landers are used for microbial methane and hydrocarbon observations on the seafloor. Have open-frame cubic structures equipped with instruments and collection chambers.

The above landers are normally deployed by a support vessel with dynamic positioning by lateral or A-frame cranes. Landers are lowered or guided to the seafloor and might need the support of a medium or work-class ROV. The ROVs flow down to the location of the lander on the seafloor and using manipulator arms can grasp tools or actuators.

3) Flat shape landers (network nodes) The mission objective of each lander can be very

influenced by their mechanical shape. Landers discussed above uses open-frames with low horizontal drag to minimize the effects of sea currents and allow water to flow through the instruments and sensors payload. Mooring weights in their bases that are left behind after the seafloor release.

Other systems uses a flat shape structure (trawl resistant frame) that seats in the bottom, presenting a low drag exposure, and uses its hydrodynamic effect to act as free downward forces that anchors the systems with the increase of seafloor currents. Fig. 8 presents a flat shape system of one of offshore communications backbone TWERC node being deployed/landing.

Fig. 8 – Photos from Node deployment and landing in the sea floor [19]

Kongsberg Maritime presented their modular subsea monitoring (MSM) design to be deployed in any kind of subsea operation for continuous monitoring of the surround environment. Created to act as a tool in the increasing environmental awareness world as a subsea alert unit for events such as oil and gas leakages from subsea installations, pipelines and risers (See Fig. 9).

Fig. 9 – Kongsberg Modular Subsea Monitoring

Similar design is presented by OceansWorks

International and their seafloor networks nodes [20]. Implemented as nodes for an interconnected subsea observatory that provides scientists with gathered data from sensor installations covering vast areas of the seafloor [19].

This systems are typically underwater observatory nodes for fiber optic and power transfer. A tool in the field of oceanographic real time data telemetry with cabled ocean observatories for high power and virtually unlimited data bandwidth. Deployed in observatories, e.g., Neptune Canada [21], Monterey Bay MARS observatory [22], Tsunami Warning and Early Response (TWERC), VENUS network (See Fig. 10).

Fig. 10 – The VENUS network node

A singular system was developed under the Km3NeT observatory project that allowed the creation of a deep-sea neutrino telescope. The Launching Optical Modules (LOM) is a spherical open-frame structure with several internal glass spheres with optical modules (sensitive photomultiplier tubes). The LOM is deployed in the sea bottom, two fiber optical and tension cables are connected to an anchor system, which releases the LOM sphere in a rotating movement. During the upward movement it releases the internal optical glass sphere modules attached to the fiber cables [23].

III. TURTLE In the scope of the TURTLE project two work segments are

planned: First, design and development of materials and structures

for deep submergence. A key part to support demonstration of dual use (civil and military) deep sea applications.

Secondly, develop a fully operational deep sea (under the project restrictions) multi-purpose vehicle capable of acting as a sea-bottom long and medium term permanence station (for observation and instrumentation) with autonomous re-positioning capabilities and multiple ascent and dive missions.

The materials and systems developed in the first point will incorporate the second line of work – multipurpose deep sea lander vehicle – allowing energy efficiency and long term presence on the ocean floor.

A. Requirements The TURTLE deep sea lander prototype is being design to

allow multiple ascend and descend cycles without the need for human intervention. Either in an autonomous pre-programmed mode were it will be collecting data from the water column, or collecting data from the bottom and then re-surfacing for satellite data transfer. It is intend to adapt the vehicle with capabilities to harvest energy in the seafloor or to surface to collect solar energy.

Another requirement is the functionality of working as a cargo transportation system. Be capable of carrying tools or material, to or from the seafloor, and collaborate with other underwater systems/vehicles.

As a lander system, TURTLE should be able to maintain moored to the ocean floor for long term operations (3 months) withstanding maximum seafloor currents of 3 knots. During the lander state the vehicle is capable of acoustic monitoring the environment, either in search for unappropriated ship crossing or harbor intrusion (military scenarios), or for marine mammals monitoring (civil scenario). It will be used for register underwater seismic activities and for other payload such as multiparametric probes or high definition video logger/processing.

A major differential functionality in the TURTLE lander is its capability for re-positioning itself in the seafloor. Underwater relocation in a radius of 500 meters without resurfacing. By means of electrical thrusters it is also capable of correcting is trajectory in the surface-bottom-surface movements.

The TURTLE deep sea lander prototype should permit to be towed from shore to the deployment site, or transported on-board by a ship-of-opportunity with a crane and winch.

The available hydrographic survey ships of the Portuguese Navy will be used as reference for the support ship to be used in the TURTLE prototype deployment.

Since the TURTLE should be deployed at any possible point in the ocean, the ships from D. Carlos Class will be used as reference, as they are appropriate for missions in full ocean depths. In particular the – NRP Almirante Gago Coutinho [24] will be used in order to define prototype physical restrictions concerning deployment from cranes.

Fig. 11 – NRP Almirante Gago Coutinho [24]

Due to the available deck space and the convenience of use one of the lateral cranes at the stern, the prototype must have a

maximum weight of 1500 Kg and be contained approximately in a box of 2m x 2m x 2m. These restrictions are typically similar to other oceanographic equipment to be deployed such as large oceanographic buoys or medium class ROVs.

This size and weight limitation is compatible with the project objectives of developing systems with reduced logistic and deployment requirements and still retaining deep ocean operation characteristics and application functionalities.

B. Basic Vehicle Design For the first prototypes, see Fig. 12, the design of the lander

was based on the energy efficiency principle and to fit the dimensions and weight specified in the Requirements to be deployed from any ship-of-opportunity.

The demand for lighter structures with better performance has emphasized the importance of efficient structural arrangements. The vehicle will use metal sandwich panels as they offer a number of outstanding properties allowing the designer to develop light and efficient structural configuration.

The vehicle should be very hydrodynamic in long distance vertical movements and (possible changing its shape) with a flat design in the seafloor to minimize the energy spend to moor it to the seafloor.

Fig. 12 – TURTLE lander – mechanical conceptual designs

A. Housings The main drive and project objective is

underwater structural elements based on Sandwich Panel Structures for applicatiosolutions. Taking advantage of the advaalready gained on the development and prodof structures for aeronautics and space aenvisioned the development of new lightweiresisting composite and lightweight metallic14) leading to more cost effective underwaand robotic solutions.

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(pressure-compensated cells). Some pressure tests are being conducted at A Silva Matos company to understand the batteries integrity strength to different pressures.

Future developments of the TURTLE lander will provide it with capabilities to harvest energy from currents, waves or surface solar panels, which are an efficient and economic mean of supplying electric power. This will extend the long-term deployments and even lead the vehicle to energetic auto-sufficiency.

Designed to act as an autonomous lander with seafloor locomotion or vertical adjustments to its movements, the vehicle was designed to incorporate 6 electrical thrusters. Solutions such as the Seaeye MCT1 or SM4, or even custom made ring thruster to diminish power consumption.

C. Variable Buoyancy System An important point to the project is the creation of energy

efficient technologies and systems. The amount of energy available in the vehicle has a direct effect on its capabilities and long term endurance. Topics such as hydrodynamic efficiency and battery technologies of nowadays underwater vehicles have increased the amount of energy available onboard. But, the use of a variable buoyancy system (VBS) will allow to save substantial energy. By changing the vehicle’s buoyancy, vertical motion can be achieved [25]–[27].

VBS will give us the capability for: dive the vehicle from the surface or lift off from the seafloor; controlling depth and rate of change of ascend/descend; assisting seafloor docking and mooring; Trimming; Emergency release and recovery.

Ascend and descend vertical movement will be achieved by the VBS and the help in the final stages, of electrical thrusters.

The use of VBS will also be a challenge in the control point-of-view. Maintain a position on the water column, increase or decrease velocities, surface or seafloor landing maneuvers are challenging tasks for the control unit. A control problem were the control variable, pump rate, is proportional to a constant rate of acceleration in the vertical, the sensed variable is depth, and involves non-linear forces and delays.

Commonly, unmanned underwater vehicles (UUVs) need to maintain a positive buoyancy at working depth, requiring pre-mission buoyancy and trimming adjustments. Using an advanced VBS would eliminate this need and save time and buoyancy failure risks.

Our variable ballast system (VBS) is designed to pump in and out seawater from a ballast tank to the ambient so that buoyancy can be made variable. Option of a pressurized ballast tank to reduce structural weight and pressure difference between ambient and internal tank, thus reducing pump power consumption.

The system components are main pressurized ballast tank and compressed gas reservoirs and electronic, pump, valves and drive motor.

When increasing buoyancy a pump unit draws water from ballast tank where gas pressure maintain internal pressure to a minimum pressure level. In opposition when taking water into main ballast tank, pressure is increased as gas need to

accumulate water volume. This way the energy required to move water around the system is reduced.

D. Sensors and communications TURTLE high operating depths present challenges for

communications, positioning, and navigation sensing and estimation. Externally mounted with acoustic USBL positioning, Doppler velocity logger (DVL), pressure sensor, altimeter, multibeam sonar, and acoustic pinger, will allow the vehicle to navigate and map in the deep sea. Internal inertial navigation system such as KVH 1750 fog IMU and GPS antenna in the surface will improve the vehicle localization and mapping capabilities.

Iridium satellite and underwater acoustic modems are the main sources of communications with the vehicle. Custom made INESC-TEC underwater communications systems are also being tested.

During the project life-line, sub-system such as hydrophone acoustic listeners and seabed seismographers systems are intended to be developed.

High definition video cameras, LED lights and line lasers are specified to perform oceanographic tasks and on-board processing that allows visual odometry.

IV. CONCEPT OF OPERATIONS The different TURTLE lander operating modes are: 1)

Multiple ascend/descend movements Mode which consists of allowing the vehicle to surface or dive with changes in the buoyancy/ballast system. Perform ocean floor long term deployments and surface if commanded or to exchange satellite data. 2) Transportation Mode which consists of transporting cargo/equipment to/from the ocean floor with autonomous precise positioning. Oil and Gas operational scenarios were the use of TURTLE and a surface small boat is easier and more cost effective then DP ships and extra work class ROVs 3) Seafloor re-positioning that consists in missions were the vehicle for own decision or the command & control order need to be re-positioned on the seafloor. Without the need to re-surface, helped by electrical thrusters for horizontal locomotion and equipped with navigation sensors, allowing it to navigate and scan the new estimated position to choose the best place to perform the new landing (See Fig. 17).

Fig. 17 – TURTLE concept of operations

V. SEA OPERATIONAL TESTS To prove all concepts, and test the TURTLE prototype

lander vehicle, several progressive field tests will be conducted in late 2014 and middle 2015. This tests will be divided in near shore and deep canyon deployments.

A. Near shore field tests These first tests will occur in late 2014, in the Atlantic

Ocean coastal waters off Sesimbra, Portugal. The tests will be conducted with the support of the Portuguese Navy and particularly the Portuguese Naval Research Centre (CINAV).

These tests aim to 1) evaluate the towing motion capabilities of the developed lander, 2) to evaluate and refine the capability of the lander to be deployed with support of a small vessel or rib boat, 3) the lander capability of be deployed in a specific position and maintain moored to the seafloor, 4) variable buoyancy system tests, 5) multiple sub-systems operational and fail-safe tests, 6) multiple ascend and descend maneuvers. For these purposes the Sesimbra shallow water operational scenario was chosen to allow an easy support by navy divers or small ROVs. It is planned to leave the lander deployed at 20 meters depth from 1 to 7 days in an endurance test (monitoring and data gathering). Fig. 18 shows the bathymetric line chart for the first operational sea trials.

Fig. 18 – Atlantic Ocean coastal waters off Sesimbra, Portugal.

A second set of dives will be performed near Sesimbra at 100 meters depths. In this tests the lander will be transported and deployed by the hydro-oceanographic ship Fig. 11 – NRP Almirante Gago Coutinho [24].

These tests aim to 1) evaluate the easiness of deploy and recover the lander in ships-of-opportunity cranes, 2) to perform underwater acoustic positioning and communications tests, 3) the lander capability of scan the seafloor and chose the optimal landing zone, 4) variable buoyancy system tests, 5) multiple sub-systems operational and fail-safe tests, 6) multiple seafloor re-positioning without surfacing.

B. Deep sea canyon deployment An important test will be conducted in a 600-1000 meters

sea canyon. The Setubal canyon lies to the south of the Nazare canyon, presents a V-shape profile and reaches 2000 meters depths near Cabo Espichel, Portugal.

This project demonstrator missions will be conducted in middle 2015 supported by the Portuguese Navy and on-board hydrographic ships. All systems and new technologies will be putted to the test in high pressure, harsh conditions, at remote and inaccessible locations.

Fig. 19 shows the estimated landing and monitoring zone for the TURTLE prototype lander. The vehicle will carry out dive and ascend long distance movements, test the cargo transportation capability to the ocean floor, and will be order to re-position in another spot to evaluate its autonomous behaviors/maneuvers and acoustic communication positioning.

Fig. 19 – Setubal deep sea canyon. TURTLE canyon deployment

VI. CONCLUSIONS AND FUTURE WORK This paper presents the TURTLE project systems and

technologies for Deep Sea long term presence. Describes the developed of platforms with new structural panels and housings that allow energy efficiency. Initial work concentrated on the development of a autonomous benthic

lander capable of long term seafloor deployments, capable of navigating and transporting equipment to/from the seafloor, and deploying it in precise locations.

Presents the different mode of operations and field operational test that will be conducted to demonstrate the conceptual systems.

Due to, the increase of economic and scientific inspections and explorations in the deep sea, maritime technologies will play a crucial role in the present future. Platforms and technologies such as the ones developed under TURTLE project will act as a major asset in the procurement for resources in the deep sea deposits. For one side the global demand for the industries to explorer rare minerals and oil and its monitoring awareness from general public. On the other hand, civilian and scientific concerns in monitoring climate changes, fish biomass, near shore sediment exchanges, rise the boundaries and alert to the need for new ocean robots and technologies.

ACKNOWLEDGEMENTS The TURTLE Project is a dual use EDA (European

Defence Agency) approved project aiming to develop new and innovative deep ocean transport technologies and materials. The research leading to these results is funded by the Portuguese Government and European Commission Regional Development Funds through the QREN program. The authors would like to thank the funding from FEDER, Operational Programme for Competitiveness Factors of Incentives for Research and Technological Development System, Project No. 38907. The project is developed in co-promotion and lead by A. Silva Matos – Metalomecânica, S.A in partnership with: INESC Porto – Instituto de Engenharia de Sistemas e Computadores, ISEP Instituto Superior de Engenharia do Porto and CINAV – Portuguese Navy Research center. This project is developed in the scope of the strategic framework set by tec4sea.

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