Living on the Seafloor. (Design Issues on Underwater Habitats. 1st part). Ocean and Space: the same goal?

At the beginning of the space era, during the 50’s, major advance were achieved in technology and the attention of the world was fixed at the sky. But other people turned their looks to other spaces, closer but far more difficult to reach, the inner space, the Oceans.
Conquering the oceans had taken longer than Space. Men had tried to reach and learn the secrets of the deep since the beginning of time.

The development of diving equipment after the WWII, gave a big push to the researchers of the oceans, leaded by Jacques-Yves Cousteau; but money was needed. On the other hand, the richest enterprise of that time, the race for the conquest of the space brought thousand of questions to the scientists, some bind the space and the ocean: “Can we make humans live on that extreme environment of the space?”, “Can we make the same in other extreme environment, like oceans?”. Suddenly a contrasted symbiosis was formed and living in the oceans became important for all the scientific community everywhere and the desire for exploring the unknown started to flow between the people. Could it be possible that the space and the ocean research just crossed their path by chance? Probably, but conquest of the ocean became as important as the conquest of Space. The dream of living on the seafloor awoke in the minds of the world.

Habitats are seafloor laboratories and living quarters where divers and scientist, now call Aquanauts, live and work for extended periods of time.

Living on the Seafloor. (Design Issues on Underwater Habitats. 2nd part). The pioneers: Why living underwater

Pushing the limits of the human body, populate extreme environments and the study of the nature of our oceans are the main reasons for the construction of underwater habitats.
The psychological and physiological response of the human body under pressure and isolation at different depths were studied in detail by Cousteau using three different habitats in France, the Conshelf I, II and III from 1961 until 1965. The US Navy and NASA also tested characteristics in design of the habitats for the pressure, interior architecture for living and safety issues on different habitats during the 60’s. [1], [2]
NASA has been using underwater habitats since the beginning of the Space program as part of regular training for astronauts; La Chalupa (now Jules’ Undersea Lodge), with the Tektite and the US Sea Lab II, were used for astronauts during the research for the Gemini missions. The MarineLab and the Scott Carpenter Station habitats were used in preliminary research for the Mars mission. The Neemo project is a regular training program for astronauts that use the Aquarius habitat. [3], [4]
Scientists at the National Undersea Research Center are still pushing the limits of the body living underwater at large depths with the Deep Sea Space Stations project on the continental shelf in Long Island Sound and the Penguin Bank next to Oahu Island. This program includes the study of life in communities underwater to populate the oceans and fish farming among others. [2]
Underwater investigation and scientific research of the biology and geology of the seas has been the main driving purposes of habitat construction also. NOAA’s Aquarius on the Florida Keys, besides the NASA Neemo program and US Navy saturation training program, also collaborated with the University of North Carolina on coral reef, seaweed, fish and sponges ecosystems researches among others. [4]

The Aquarius Habitat at the Florida Keys [4]

Atlantis II project of MIT, aimed to investigate the Abyssal hydrothermal vent fields, the geology of the area, the ecosystem that live in those extreme pressures and temperatures and organism that use chemosynthetic energy. [5]
Even though science and research have been important for habitats development, new investment is coming for other purposes. The technology is already at a stage where pleasure is getting involved in habitat development. Jules’ Undersea Lodge in Key Largo is one of the first underwater hotels that can offer a nice underwater suite with hot water shower, air conditioning, DVD, unlimited dives and other luxuries. The habitat can accommodate up to six people, a scientist team, a group of astronauts on training, or a newly wed couple. [6]
From Jules Verne novel “20.000 Leagues under the Sea” to “The Abyss” and “The Sphere”, writers and movie makers have been using the subject of living underwater to touch the soul of the lovers of the Oceans.
People are looking for new environments and the sea offers unimaginable beauties that lead the industry to develop new ways to explode that interest and make the oceans part of the normal life of the public.

Living on the Seafloor. (Design Issues on Underwater Habitats. 3rd part). The Basics

Knowledge of ocean conditions is important to development of underwater habitats to confront the forces of the environment. Basic needs for the human being to live on extreme and limited conditions have to be fulfilled.
Depth is the main driving mechanism that will affect the basic design and behavior of the human body for living on those conditions.

Pressure and Depth
External pressure product of the weight of the water column will increase with depth. Once the operational depth of the habitat has been established, the pressure at that depth will determine the design and characteristics of the systems for the habitat.
Access to the seafloor by divers and the breathing gases will also depend on depth as the physiology of the human body will change under pressure
The ocean life will also vary with depth and the ecosystems that lives at the coastal shelf will be completely different from the ones that live in the deepest areas of the oceans. As a consequence, the research purpose should be also considered for the design and the operational depth.

The human body under pressure [7]
As the human body is 95% composed of water, including bones, muscles, solid organs, nerves, etc., the effect of the increase on pressure is transmitted and undiminished in all directions making the pressure tolerated at any depth. The body also contains air filled compartment with flexible walls, like the lungs that will compress until certain limits. The air filled compartment with rigid walls, like sinuous and inner ear have to be equalized to avoid damage.

The human body needs air to breath at atmospheric pressure, the increase in depth causes changes to the breathing gas and these changes will have a direct effect on the tissues of the body. Because of these changes, different proportions of gases, like Helium, have to be added to the breathing mix to support the human body at greater depth. The saturation of the tissues with gases at depth is used to prolong the stay of people underwater and long decompression procedures are needed to take the aquanauts back to surface.
Even with saturation diving using mix gases, there is still a limit of depth that the human body can stand and exploration of the ocean at more that 500 meters will required closed habitats. The closed habitats will maintain the internal pressure lower that outside to support appropriated conditions for the human body and the structure of the habitat will have to resist that difference. [10]

Environmental Constraints [8]
Major environmental factors of the ocean will change with pressure and life on the ocean had adapted to those changes. Light, temperature, currents, salinity, density, bottom conditions are major environmental constraints that have to be recognized and will influence visibility, living conditions, communications and safety among others.

Living on the Seafloor. (Design Issues on Underwater Habitats. 4th part). The Habitat and Support Systems

Structure and Materials [9]
Open bottom habitats with moon pools will have the same internal and external pressure for the air to push the water out of the habitat. The structural design is not as complex as the closed habitats for large depths, but decompression is normally accomplish within the habitat and differential pressure between the internal compartments and the exterior will exist.
The most efficient structural arrangement to support hydrostatic pressure resists the loads by direct stress without loss of stability or buckling. Spheres are the most efficient shapes for high depth but very difficult to manufacture and the space for the arrangement of internal systems could be a problem. Cylinders with ring stiffeners provide a better arrangement for distribution of the space without making the external walls to thick and heavy.

Blueprints fo the Deepcore II. From the movie The Abbys

For structural integrity the more important aspects are collapse strength or the resistance to the hydrostatic loads, the dynamic loads and fatigue, but materials, weight, corrosion resistance and method of fabrication will play an important role on the design of the structure and components. Basic structures can be attached together to form different compartments as modules for different purposes.
The end closures and opening in the shells are considered week points; the reinforcing and seals next to the openings, hatches, viewing ports and hull penetration couplers or instruments, needs special attention on design and construction. Safety factors have to be carefully established for the materials and structural design.
As the habitat will be a compartment full of gases, buoyancy of the structure is controlled by the weight, anchoring the habitat to the seafloor and ballast. For an open bottom habitat with aquanauts in saturation, the rapid ascend of the habitat to the surface because a positive buoyancy and lost of ballast, will represent dead of the occupants.

Breathing Gases [10]
For longer stays underwater and unlimited supply of breathing gases, the surface supplied system is the best option. The appropriated mixtures of gases can be sent down by hoses or pipes for short distances and the supply can be monitored from the surface at the support ship or from land. Oxygen supply can be sent down with other gases on a regular bases and keep in compressed bottles to be mix in the habitat as appropriate but a large supply will be needed and also storage capacity within the habitat. In any case, bottles of compressed gases have to be attached to the habitat for emergency situations.
Other important equipments of the breathing systems are the scrubbers that will remove the CO2 produced by the respiration. Helium recovery for deep saturation open habitats will reduce the cost of the operation and some detectors added to the systems will alert on any trace of contaminants within the breathing atmosphere.

Power and Communications [5], [9]
Stand alone batteries technology is not enough to power an underwater habitat for long time, but are essential for emergency situations. Batteries can be charged using cables for electrical transmission and as a primary power system. The source could be a support buoy with solar panels or a generator on the support ship. For higher depth, drag forces on the cable, the weight and currents will make this a very difficult task. Cables laid on the sea floor to power from shore or a close island is another method. Major limitation is that as the distance increases the transformer underwater has to be bigger. New technological developments aim to increase the transmission of DC current over long distances. Nuclear power generation or subsea generators could be considered but the cost is very high and the technology is complex.
Communication underwater is very difficult to achieve by wet links and fiber optics is nowadays the best mechanism for transmission of data. Cables can be connected to a surface buoy with wireless system to the base, a support ship or shore with similar limitations on distance and power. Pingers and emergency communication buoys are added in case of emergency.

Heating and Air Conditioning [10]
Conditioning of the habitat for living includes the control of temperature and humidity levels. As depth increase, temperature will decrease and heat will be transferred from the habitat to the water through the metal surfaces, this transference has to be controlled with isolating materials on the surfaces and heaters. On the other hand compressed air has to be cooled down before being transferred to the compartments to be breathable. Balance of these processes is necessary to maintain an appropriate temperature. The use of helium will increase the loss of heat from the body and heaters are absolutely necessary. In those closed environments, humidity control is important to avoid infections and fungus. Circulation of dry air or gases will need to maintain lower humidity levels.

Viewing [9]
The view of the seafloor site is one of the most attractive things of the underwater habitats. Some habitats are designed with big domes of plexiglass or reinforcement glass panels. From the design point of view making domes and view ports is difficult and as for the structure, reinforcement of the open holes and sealing is very important. Transparent materials have to be selected based on their resistance. At major depth the view ports become smaller. For safety reason the habitats should have a hatch or protective panel that can be closed to avoid damage of the domes or port when the habitat is moved or for emergency in case of failure or crack on the view ports.
Solar light will penetrate the ocean and will be attenuated with depth. Artificial light is necessary to improve visibility and detail viewing of the exterior. Cameras are used to monitor and record the surrounding environment or the exterior of the habitat.

Access and Transportation [5], [10]
Access to shallow water habitats can be done by divers just swimming into the moon pool. For deeper open habitats with mix gas atmospheres, the compression process is a little longer and complex. Compression for commercial saturation diving is done in a chamber on the support ship where after one or two days to avoid physical problems, the divers enter into a close bell which is lower down to the operation depth for the diver to go out and probably transferred to the habitat. Above the diving limits where the inside pressure is maintained at atmospheric pressure, submersibles or bells have to couple in the hatches of the habitat to allow the transference of personnel.


For the assent to surface the aquanauts have to spend some time in a decompression chamber to relive the gases absorbed by the tissues safely. The decompression can be done in one compartment of the habitat or in a chamber on the surface using the same bell as before.
The decompression is a long and delicate process that has to be carefully monitored. In some cases there is no need for decompression, like close habitats at atmospheric pressure with a submersible for transference.

Logistic (Food, water and waste disposal) [5]
Provision of food almost ready to eat will facilitate living, as open flames are not desirables on those close and sensitive environment and space is compromised. Chemical reaction for heating or microwaves could proportionate a safe easy way to heat the meals. Fresh water for personal consumption has to be transported or sent by hoses. Waste water and waste disposal can not be dumped outside. Special collectors, recycling or transported to the surface are some of the methods that can be used.

Living on the Seafloor. (Design Issues on Underwater Habitats. 5th part). Other considerations

A good design is always supported by backup systems, maintenance procedures, safety procedures and emergency procedures.

Support systems reliability [8]
Being complex systems that support life on extreme conditions, the reliability has to be high for each component. Backup systems for gas supply, power and communications are necessary to control emergency situations or failures.

Maintenance
Corrosion is one of the major attempting factors against integrity of metal structures underwater. A maintenance program of the structure, painting and integrity monitoring is necessary to avoid catastrophic failures. Maintenance of the life support system is also very important. Scheduled inspection procedures will ensure safety of the structure and the systems.

Cousteau Conshelf

Safety and Emergency
Risk is involved on underwater habitats and emergency situations can occur. Every situation must be tackled immediately with the backup systems, safety and emergency procedures.
Some of the situations that can occur on the underwater habitats and will require an immediate action are flooded compartments, leaks, decompression sickness or medical problems, lack of communications, power or breathing gases, structural damage, structural damage, bad weather, earthquakes, etc. Each one has a different effect and could have serious consequences if countermeasures are not carefully plan, maintain or effectively used.
Safety procedures must be properly accomplished to avoid emergency situations. Personnel must train on procedures in case of emergencies.

Living on the Seafloor. (Design Issues on Underwater Habitats. 6th part). Underwater Architecture: Luxury underwater

As we move into new eras when science and technology is moving to general public, architectures are looking to please luxury and style on the underwater habitats. Without the need for sophisticated life support systems, the construction of new housing development with underwater chambers or living rooms on cliffs and coast mix the pleasure of living underwater or the fascinating view of the sea from the inside with the facilities of a regular building using concrete, metals, new materials and new construction techniques. Splendid buildings can be seen on the designs of the naval architect Giancarlo Zema. [11]

Poseidon Undersea Resort drawing [12]

But the vision of a totally underwater environment for living and pleasure is getting out of the design table and has started to get more support. The design and technology of underwater habitats, for research or pleasure, will keep growing as there is still so much to see and share on the seafloor.

Living on the Seafloor. (Design Issues on Underwater Habitats. References).

Francisco Javier Tinoco Pineda
Materials Engineer, mention Metal-mechanics
ROV Pilot/Supervisor and Commercial Diver

For the Underwater Technology Module
MSc. Offshore & Ocean Technology
Subsea Engineering
Cranfield University
United Kingdom

References
1. http://www.cousteau.org/en/heritage/inventions/conshelf.php. [3/24, 2006].
2. http://my.fit.edu/~swood/History_pg5.html. [3/24, 2006].
3. http://www.onr.navy.mil/focus/blowballast/people/habitats2.htm.[03/24, 2006].
4. .http://www.uncw.edu/aquarius/index.html. [03/13, 2006].
5. http://web.mit.edu/12.000/www/m2005/a2/finalwebsite/index.shtml. [03/24, 2006].
6. http://www.jul.com/. [03/24, 2006].
7. Strauss, Michael, and Igor Aksenov. 2004. Diving Science. USA: Human Kinetics.
8. Busby, R. F. 1976. Manned submersibles. Office of the Oceanographers of the Navy.
9. Myers, John ed. 1969. Handbook of ocean and underwater engineering. USA: North American Rockwell Corporation.
10. Cranfield University, R. Allwood, and S. Tetlow. 2005. Diving science and technology module notes - commercial diving, saturation diving systems.
11. http://www.sub-find.com/jellyfish.htm. [3/24, 2006].
12. http://www.poseidonresorts.com/index.html. [3/24, 2006].

Robots submarinos: videojuegos verdaderos

Los ROV (Remote Operated Vehicles) o Robots Submarinos como se les conoce comúnmente son equipos de mucha complejidad utilizados en operaciones submarinas comerciales o de investigación.

Phantom HD2+2 de Deep Ocean Engineering, perteneciente a Sea Tech de Venezuela.

A medida que la industria petrolera realiza actividades de perforación en el mar en zonas más profundas, los costos de realizar actividades submarinas con buzos se hacen cada vez más complejas y costosas. Los robots submarinos representan una solución de vital importancia para una industria que se desarrolla cada vez en mayores extremos.

Los robots submarinos son equipos eléctricos o electro hidráulicos, operados desde una cabina en una instalación fija en superficie o embarcación a través de unas palancas de control o “joysticks”; estos mandos permiten al Piloto operar los motores y desplazar al robot en las tres dimensión bajo el agua. Las señales e instrucciones son trasmitidas desde la cabina de operaciones hasta el equipo mediante un cordón umbilical compuesto de una cantidad de cables para el transporte de corriente, señales e imágenes.

Los robots poseen una o varias cámaras de video con lámparas que permiten al Piloto realizar observación, inspección o una operación determinada, incluso con muy mala visibilidad. Estas cámaras permiten grabar las operaciones, una inspección de tuberías e incluso hasta tomar fotografías estáticas de objetivos.

La navegación se realiza mediante una cantidad de instrumentos y programas como el sonar, brújulas electrónicas y los sistemas de localización acústica. Estos permiten orientar y localizar al robot bajo el agua con respecto a la embarcación, determinar su posición en coordenadas reales, localizar otros elementos sumergidos e incluso registrar las posiciones de estos elementos bajo el agua.

Dependiendo de su clasificación y el tipo de trabajo para el cual están diseñados, los robots también poseen una cantidad de instrumentos o herramientas adicionales; entre estas herramientas podemos mencionar instrumentos para realizar ensayos no destructivos, brazos manipuladores, herramientas para accionar válvulas y otros.
Los robots se clasifican según su capacidad de trabajo y herramientas.
Los ROV clase I o de simple observación, son vehículos relativamente sencillos con una cámara de video y que se utilizan para realizar inspecciones a tuberías y estructuras submarinos. Son bastante livianos y pueden ser desplegados sin necesidad de grúas. Muchos de estos robots se utilizan para las investigaciones científicas.

Los vehículos clase II poseen además de las herramientas de video, instrumentos de localización como el sonar y herramientas para realización de ensayos no destructivos. Estos vehículos pesan alrededor de 150 kilogramos y algunos poseen brazos mecánicos simples de hasta dos funciones.

Los vehículos clase III o de trabajo pesado pueden pesar hasta 3 toneladas, utilizan la potencia hidráulica para accionar sus herramientas y superan los 6000 pies de profundidad, según el diseño. Estos equipos se utilizan en la industria petrolera para una gran cantidad de actividades.

CANYON QUEST 10,000-ft. Electric Work Class ROV

Existen vehículos clase IV que son aquellos que se desplazan en el fondo con orugas como tractores o son arrastrados por una embarcación sin potencia propia como los sonares de barrido lateral. Los vehículos clase V son vehículos en desarrollo.

En Venezuela la actividad submarina con ROV comenzó de manera constante en el año 2001 cuando la empresa Sea Tech de Venezuela C.A. adquirió un ROV modelo Phantom HD2+2 (vehículo de inspección y survey clase II), fabricado por Deep Ocean Engineering en California, para realizar inspecciones en tuberías submarinas para la compañía Shell Venezuela en el Lago de Maracaibo. Este vehículo cumplió con las metas trazadas de una manera eficiente. Se redujo la utilización de buzos para inspecciones generales de tuberías sublacustres, y los factores de riesgo, aumentando la productividad de los buzos al utilizarlos para las inspecciones detalladas de objetivos definidos. En muchos casos se ha utilizado al robot para verificar condiciones de riesgo antes de enviar a los buzos a realizar un trabajo.

El ROV es una ayuda útil en las operaciones de buceo. Sus habilidades para monitorear científicamente y verificar condiciones de trabajo, han demostrado ser un beneficio de seguridad positivo, al reducir el riesgo de exposición del buzo.

Los nuevos proyectos de explotación petrolera en las costas venezolanas han despertado la necesidad de aumentar el desarrollo de la industria submarina venezolana. Estas actividades representan una gran cantidad de puestos de trabajo con muy buena remuneración en un futuro no muy lejano para gente con ganas de afrontar el reto.

Francisco Tinoco Pineda
Piloto Supervisor de ROV y Buzo Comercial
Coordinador de Operaciones Submarinas
Sea Tech de Venezuela C.A.

Publicado por www.scubanews.com.ve el 22/09/2005