Upgraded research vessel a huge advancement

NIWA Media Release 12 December 2010

Upgraded research vessel a huge advancement for New Zealand science and exploration

NIWA today welcomed home RVTangaroa, New Zealand’s only deepwater research vessel, after a $20 million dollar upgrade to enhance its ocean science and survey capabilities.

Tangaroa is the only ice-strengthened research vessel in the country and NIWA’s base for major offshore, international science work. The vessel is 20 years old, and the upgrade will now enable Tangaroa to meet New Zealand’s ocean research and survey needs for the next 20 years.

The vessel has spent the last five months in Singapore being extensively upgraded, including the installation of a dynamic positioning (DP) system.

A DP system is a fully automated system that allows the vessel to remain fixed in a specific position at sea, despite wind, waves, and currents. It also allows the boat to precisely navigate a straight path.

The system installed on Tangaroa is a DP2 system which uses electrically powered thrusters and computerised controls to fix the vessel to a specific area, guided by satellite positioning or transponders on the seabed.

DP2 capabilities are essential for ocean science and marine operations undertaken by oil, gas, and mineral industries, where new technologies often require vessels to hold a steady position. This includes the deployment and use of remotely operated vehicles (ROVs), autonomous underwater vehicles (AUVs), manned submarines, seafloor observatories and other equipment temporarily fixed to the seabed, such as seabed samplers and rock coring equipment. Dynamic positioning is also very important when deploying divers or working around marine construction works, such as oil and gas platforms or pipelines.

There are no other New Zealand-based vessels with DP2 capabilities, meaning New Zealand is becoming increasingly reliant on foreign vessels for marine work requiring precise positioning.

NIWA’s General Manager of Research, Dr Rob Murdoch, says the upgrade to Tangaroa provides New Zealand with a valuable asset to help advance ocean science, surveying and exploration.

“International demand for research and survey vessels with DP2 capabilities has increased a lot over the last few years, especially with the heightened activity in the exploration industries. By installing the DP2, we can provide these capabilities without companies having to look offshore for foreign vessels to do the job. That’s a huge advancement for New Zealand.”

“Tangaroa has always had excellent research capabilities, but these improvements will really allow NIWA to meet the future demands of its ocean science and commercial clients. Many oil and gas exploration companies demand dynamic positioning capabilities on vessels as a safety and environmental requirement and now we can provide a vessel locally.”

Other improvements to the vessel included installing new laboratories, upgrading air conditioning systems, refurbishing winches, the galley and dry stores, installing a new deep sea winch and a bridge wing to view gear deployments, and stripping and re-painting the vessel.

Tangaroa will remain in Wellington for the next few days to undergo final sea trials, before being deployed on its first voyage of 2011 – a fish stock trawl survey over the Chatham Rise.
To illustrate this story:
From 2pm, you can download photos and high-quality, aerial footage of RV Tangaroa arriving in Wellington Harbour this morning, along with an animation of the dynamic positioning system:
http://ftpmedia.niwa.co.nz/tangaroa_refit/
Credit: NIWA
Wellington-based media: Tangaroa is currently berthed at Aotea Quay. Access to the vessel is limited; port authority security clearance is required.

More information:
1. What is a dynamic positioning (DP) system?
A dynamic positioning (DP) system is like a computerised anchor. It’s a computer controlled system to automatically maintain a vessel in a fixed position at sea (within a few metres) by using its own propellers and thrusters.
A DP system typically includes underwater propulsion hardware, diesel-electric generators to supply power to drive the propulsion hardware, control computers and software, and high-resolution positioning systems (usually using GPS and/or transponders moored to the seabed).
There are three different classes of DP system available:
DP1 - has a computerised system to maintain the vessel on location.
DP2 - has identical underwater components to a DP1 but also has two completely independent diesel-electric power generators, switchboards, computer and positioning systems, so that if any of these fail the vessel will remain in position.
DP3 - houses all its dynamic positioning equipment in separate, sealed engine rooms as an extra safety precaution. Generally DP3 vessels must be purpose-built and are rarely used.
In New Zealand there are no other vessels with DP2 capabilities, although a few have DP1 capabilities.
2. What does the installation include?
The new DP2 system on Tangaroa includes:
A new stern thruster (800 kW).
An increased capacity bow thruster (368 to 600 kW).
A retractable azimuth in the bow. (A retractable azimuth is an electronically driven screw system that can be lowered beneath the vessel and rotate 360. The screw then pushes the vessel in the desired direction – forwards, backwards, or even sideways).
A new bow module to house the azimuth and bow thrusters.
Two 1440 kW generators to power the new thrusters.
A High Precision Acoustic Positioning (HiPAP) system.
A computerised control system.
A pipe through the hull to allow sensitive electronic equipment to be deployed below the vessel.
To see an animated demonstration of how these components work, go to: www.niwa.co.nz/our-science/vessels/tangaroa
3. What kind of conditions can the DP2 withstand?
No vessel can maintain a fixed position in extreme weather conditions, even with a DP system. However, the DP2 system installed on Tangaroa means the vessel can stay in a fixed position in currents up to 2 knots, a swell of up to 3 metres, or winds up to 45 knots. These are typical marine conditions Tangaroa might encounter on voyages around the world.
4. How accurately can the DP2 hold the vessel in a fixed position?
The DP2 can hold Tangaroa within a few metres of a fixed position (which is very accurate considering Tangaroa is 70 metres long and weighs more than 2000 tonnes). The system also allows the vessel to accurately move along a precise path. These added functions will greatly enhance the vessel’s ability to deploy or operate scientific and other equipment including remotely operated vehicles (ROVs), autonomous underwater vehicles (AUVs), manned submarines, seafloor observatories, and other equipment temporarily fixed to the seabed, such as seabed samplers and rock-coring equipment. Being able to hold a steady position is also very important for safety when deploying divers or working around marine construction works, such as oil and gas platforms or pipelines.
5. How will the upgrade assist New Zealand science and exploration?
RVTangaroa is a 20-year-old vessel, and only halfway through its estimated useful life. While the vessel has excellent capabilities as a fisheries research vessel, there are an increasing number of new technologies now used in ocean science and oil, gas, and mineral exploration work that require dynamic positioning systems. Without the DP system upgrade, opportunities to use Tangaroa for these activities would be severely limited in the long term, and could impact on the vessel’s commercial viability.
Local access to a vessel with dynamic positioning is a huge asset to the country and will help advance ocean science, and oil, gas, and mineral exploration within New Zealand.
6. What other advantages does the DP2 system provide?
Prior to the upgrade, Tangaroa had only one engine, gearbox, shaft, propeller and rudder, and the failure of any of these parts would have incapacitated the vessel. Though Tangaroa has not had any serious incidents of this type, it is a significant risk (both to safety and financially), especially when the vessel is operating in high risk areas such as Antarctica. Installation of the DP2 provides an alternative propulsion system if any of these components fail.
Other advantages of the new system include:
Increased manoeuvrability – making it easier to change position quickly and accurately. The new system also allows the ship to move backwards, forwards and even sideways if needed.
Unlike a physical anchor it is not dependent on water depths and cannot be obstructed by debris on the seabed. The system allows the vessel to be ‘anchored’ at depths of 4000 metres or more.
7. What other upgrade work was done on the vessel while it was in Singapore?
Because Tangaroa can spend most of the year (280-340 days) at sea, there is not often time to undertake other upgrade work on the vessel. Therefore, while the DP system was being installed other improvements were also made to Tangaroa including:
Installing new freezer space.
Installing new laboratories.
Upgrading existing alarms and air conditioning systems.
Refurbishing the galley and dry stores.
Installing a deep-sea winch capable of storing 10 km of cable.
Replacing deck piping and cabling.
Installing a new gear box.
Refurbishing the propeller, shaft, and rudder.
Stripping and repainting the vessel.
8. How much did the upgrade cost and how long did it take?
The total cost of the upgrade to Tangaroa was approximately NZ$20 million. NIWA began planning for this project in 2007. The upgrade work itself took five months to complete (including one month in dry docks and around a month travelling between Singapore and New Zealand).
9. Where was the upgrade work done?
The preparatory work, carried out in 2009, was undertaken by a consortium based in Whangarei and re-ballasting of the vessel was done by a company in Wellington.
The installation of the DP system was carried out by Singapore Technologies Marine Ltd at their Singapore dockyard. The suppliers of all the major specialised components (such as thrusters and switch gear) for the DP system are also based in Singapore.
Other components of the upgrade were sourced from New Zealand and taken to Singapore (including the cooling vents and the hull paint).

Quirky facts about the Tangaroa upgrade:
About 20 kilometres of new wiring were installed.
207 tonnes of new ballast were installed on the vessel.
The new gear box weighs 3.5 tonnes and measures 3 m long by 1 m wide.
The new bow module weighs 42 tonnes.
The two new generators each weigh around 12 tonnes.

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