Research vessels

Designing Polar Research Vessels

By: M A Atmanand, M Ravichandran and D Rajasekhar, The authors are Director, National Institute of Ocean Technology (NIOT), Chennai Director, National Centre for Antarctic and Ocean Research, Goa and Senior Scientist and Group Head of Vessel Management Cell, NIOT.
Observations in Polar Regions are essential for understanding changing climate. This article provides insights into how a floating laboratory—the Polar Research Vessel, is designed and built to meet the mission requirements of scientific users.
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Research vessels are the primary source of oceanographic observations and will remain so for the foreseeable future. Science is likely to be conducted in increasingly remote and environmentally challenging areas, including the Polar seas in the decades to come. Thus the need to build an ability to operate with minimal interruptions from natural elements remains unchanged from the days of the Challenger Expedition—the first scientific oceanographic exercise of 1872–76 (Rajasekhar et. al, 2014).

Research vessels fulfil an important need of carrying out research at sea—helping in the detailed analyses and studies of the oceanic arena for various purposes. The construction and the structural composition are thus customised to suit the operational needs. These vessels are designed and built to face the toughest environmental conditions at sea.

In the earlier days research vessels were fairly basic as compared to the state-of-the-art vessels being built now. The trend of converting only ship into research vessels was challenged by the heavy demands and increasing complexity of investigation in the areas of oceanographic research—physical, biological and chemical oceanography; marine geology and geophysics; ocean engineering and atmospheric science—all in one expedition. In order to carry out multi-disciplinary research in an extreme environment, the need for specially designed research vessels came to light.

Polar research vessels

Providing a platform and mechanisms for Polar scientists to identify current and emerging research goals, Polar research vessels (PRV) help advance earth system science and, particularly assist better understanding of the Polar Regions. PRVs are versatile ocean observing platforms equipped with advanced scientific equipment and mechanical handling equipment for Polar expedition, oceanic survey, observations, explorations and logistics. Generally, the purpose of research vessels differs from defence/cargo vessels even with respect to design and construction (extreme sea/weather conditions, low free board and low windage area, large deck space) and various other sophisticated machineries/material handling equipment onboard.

National Centre for Antarctic and Ocean Research (NCAOR) established in April 1999 is mandated to plan, promote and execute the Polar research programme of India, as the nodal agency. The major outcome of Antarctic expedition being  conducted by NCAOR includes systematic geological mapping covering an area of about 20,000 sq km in east Antarctica, discovery of about 35 new species of microbes and monitoring of fluctuations of sea ice extent.

 Identification of scientific mission requirements

Preparation of scientific mission requirements (SMR) is the primary foundation for designing a research vessel. The main objective is to identify scientific instruments (hull mounted) needed and factor-in other requirements including various handling systems, winches and more.  These scientific needs would also include a laboratory and a working deck area in the context of various mission profiles. While designing a PRV, a gamut of scientific perspectives have to be considered in addition to normal naval architectural challenges.

Special requirements include ice breaking capability, reduced underwater radiated noise so that life in the sea is undisturbed and safety  of scientific equipment onboard is ensured. Engines need to be selected in such a way that optimum fuel efficiency and low noise and vibration levels are met. Propeller design is also very important since the propeller noise is the most critical parameter to be considered while designing a PRV.

Several studies need to be carried out with respect to the sea-keeping capability and comfort of the crew/scientists. Such a ship will be required to supply fuel and provisions for the expedition team at India’s Bharati and Maitri research station in Antarctic (Nayak, 2008). It is also to provide support for helicopter operations based on requirement of logistics/rescue through its helipads. Hence the vessel should have a flight deck onto which a Kamov/Super Puma or similar helicopters can land and take off while the vessel is heaving in a direction favourable for the operation.

It is essential to identify deck machinery equipment that can perform oceanographic operations in extreme weather conditions. The most challenging part of whole design is to cater to all the scientific and logistic mission requirements in one vessel. A lot of requirements are contradictory—good for one but not good for the other. For example, what is good for noise is not good for efficiency and what is good for ice breaking is not good for sea-keeping. The design should be thus undertaken in such a manner that the overall compromises are minimal.

Critical design aspects

Reducing underwater noise-silent class: Research vessels rely on a controlled underwater noise emission in order to perform their tasks proficiently and effectively. The vessels that fulfil the requirements applicable are given a class notation (R)-Research. Very low levels of underwater radiated noise are vital for the underwater survey work to be undertaken by the scientists onboard (Abrahamsen, 2012). Designing the propeller and rudder together delivers optimum performance. The engines are carefully installed in three separate pieces. The first part of the engine to be fixed is its ‘double elastic base’. This huge rigid skate, which sits on rubber noise buffers, is an integral part of the ship’s underwater noise radiated design. Once this is achieved, then the engine is placed followed by the alternators (DNV GL, 2010).

Asymmetric hull design: An asymmetric hull allows operating not only ahead and astern, but also obliquely (sideways) with a large angle of attack. This way the relatively small oblique icebreaker is capable of opening a wide channel in ice.  In case of oil spill, the vertical side of the asymmetric hull can be used as a large sweeping arm that guides oil floating on the surface to a built-in skimmer as the vessel moves obliquely through the oil slick.

Unique Propulsion System: Azipod is a podded propulsion system, azimuthing through 360°. It incorporates an electric single or double wound AC motor mounted directly on the extremely short propeller shaft. The motor drives a fixed-pitch propeller. The electric motor is controlled by a frequency converter, which produces full nominal torque, available in either direction over the entire speed range. The propeller revolutions per minute (RPM) can be freely optimised according to the varying hydrodynamics of each project. The principle advantage of using an azipod propulsion system includes—easy handling, low noise, low vibration, higher redundancy, fuel efficiency, lower emissions, excellent harbour manoeuvring and comfort of crew/scientists.

Designing with the sensitive Polar environment in mind: The primary requirement is ice breaking capability and the vessel should be capable of breaking ice from a thickness of 0.2 to 1.5 m with its unique hull design, the integration of the propeller and rudder with the hull and the use of powerful one efficient engines. Engines also need to provide both mechanical propulsion and electric power generation onboard and run on low sulphur fuel. Variable valve timing and an intelligent system that responds to load, needs to ensure that the engine always receives the ideal amount of air for maximum responsiveness and efficiency. The engines also need to be fitted with emission reduction systems —selective catalytic reduction (SCR) systems. This is integrated into the electronic engine management system and monitors and controls all key engine functions and exhaust after treatment. Thus, the vessel needs to comply with both the International Maritime Organisation (IMO) Tier II and Tier III rules (ASCOBANS, 2010) (Table 1).

Selection of hull plate: Design of ice class vessels are required to meet regulations set by classification societies (e.g. DNV GL, ClassNK, ABS etc), simply known as class. Each class specifies their own rule regarding computation of loads, selection of materials and class of ice. Since the nature of loading on the vessel is different depending on the service area, each vessel needs to be designed accordingly. There are vessels designed to cut through thin ice in lower latitudes as well as through thick multi-year ice in the Polar regions. The class also gives notations to the vessels designed based on their rules. In the case of Polar class vessels or icebreakers, for operation in the Arctic/Antarctic region, the notation range from PC-1 to PC-7  (International Association of Classification Resources, 2006) (Table 2).

Battery Power: The vessel needs to have electrical systems with at least 5 MW peak effect battery capacity. The batteries reduce the ship’s fuel consumption, emissions, noise and vibrations, as well as increasing redundancy and, consequently, safety. The use of electric winches instead of hydraulics whenever possible also reduces the risk of contamination.

Endurance, comfort and safety: A large proportion of the vessel’s passengers are researchers and environmental scientists, not mariners. Passenger comfort is therefore vital if they are to perform their duties effectively.

The vessel are made capable of undertaking voyages of up to 120 days and are entirely self-sufficient in fuel and supplies, whilst optimising passenger comfort and safety. Clever design uses all of the ship’s available volume, having everything in the right place operationally and finding the optimum balance of trim, stability and weight. The vessel is also able to hold its own waste water, reducing the impact on the sensitive Polar environment. Automation and control systems allow the captain of the vessel to control every aspect of the ship’s operation simply, efficiently, and above all, safely (International Maritime Organisation, 2010).

India’s position in world map

Ever since the first Indian Scientific Expedition to Antarctica way back in 1981, India has been managing the transportation of the expedition personnel and cargo to and back from Antarctica through chartered vessels. However, as these vessels were basically ice-class cargo vessels, it rendered them unsuitable for oceanographic research. Taking into consideration the growing need of the scientific community to initiate studies in the frontier realms of ocean sciences, the uncertainty in the charter-hire of Polar vessels, ever escalating chartering costs  and the expansion of India’s scientific activities into the Arctic, Antarctic and Southern Ocean, the Ministry of Earth Sciences (MoES), decided to explore the feasibility of constructing and commissioning a Polar research vessel which can cater to both the scientific and logistics aspects of the Polar and Southern Ocean programmes.

The Indian government authorised the National Centre for Antarctic and Ocean Research (NCAOR), Goa to acquire a PRV in October 2014. The PRV is expected to contribute to India’s scientific expeditions and to sustain research at two Indian bases in Antarctica (Maitri and Bharati) and also dovetail research initiatives in the Southern Ocean domain in the proximal regions of the Antarctic continent. It could also widen the thrust on Arctic research disciplines, undertaken through Indian Station Himadri, in addition to providing a suitable research platform for other ocean research programmes (PIB, 2015).

Owning a ice breaker vessel will reduce India’s dependence on foreign vessels and give scientists freedom to plan diverse scientific programmes. The PRV will also cater to replenishing life saving commodities such as fuel, food and medicines as also other equipment such as snow vehicles and scientific equipment to the two Antarctic stations, thereby saving huge foreign exchange.

When built, the 132 m long PRV will be one of the most advanced scientific Polar research vessels in the world, capable of spending 120 days at sea without resupply.  It would be a proud moment for India to acquire a new PRV, which is likely to play a pivotal role in helping future scientists understand how the changes in the Arctic and Antarctic will impact global climate.

 References

Abarahamsen K., 2010. The ship as an underwater noise source, Conference Paper in Proceedings of meetings on acoustics,  Acoustical Society of America, 17(1): 070058.

ASCOBANS, 2012. IMO Marine Environment Protection Committee (MEPC) 60th Report, Noise from commercial shipping and its adverse impacts on marine life, Available at: https://bit.ly/2PBTvmf

DNV GL, 2010. DNV Silent Class Notation, Part 6, Chapter 24, Available at: https://bit.ly/2MOCuq9

International Association of Classification Societies, 2016. Requirements concerning Polar Class, Available at: https://bit.ly/2PzCjNZ

International Maritime Organisation, 2010. Guidelines for ships operating in Polar water,
2010 Edition, Available at: https://bit.ly/2NguQBN

Nayak S., 2008. Polar Research in India, Indian Journal of Marine Sciences, 37(4).

Press Information Bureau, 2015. A Polar Research Vehicle to be acquired at a cost of over 1050 crore rupees for Research in Antarctica, Artic and in Southern Ocean Region, Ministry of Earth Sciences, April 23.

Rajasekhar D., D. Narendrakumar, P.S., Ananthakrishna, K. Ramasundaram and N. Ravi, 2014. Indian Research Ships Features and Future, Science Reporter, 51(8): 32-37.

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