Rena Owners Proposal: Leave the Rena As It Is Now on the Reef
Rena Owners proposal: Leave the Rena as it is now on the reef
From the Full Wreck Removal Feasibility AppraisalReport
Date: 18th June 2014
Done by TMC Marine (instructed by The Swedish Club (TSC) owners of Daina Shipping Company, the Owner of the RENA )
a)Parts of the hull sections have antifouling paint (TBT) applied which when disturbed will release further paint flakes into the environment which will end up in sediments.There is TBT present on the ship’s aft section. There is the potential for TBT to get into the environment through paint flakes such as would be released with abrasion or further salvage involving cutting or from the wreck being moved in storms.
b)There is a small amount of fuel oil (around one tonne) remaining in the wreck, mainly caused by clingage to pipes and steelwork.There is the possibility of this being released during cutting operations or during storms
c) Most cargoes remaining within the wreckage of the Rena are considered to be environmentally benign (that is, having no significant effect and causing no significant harm).There was one container holding 21 tonnes of copper clove within the remnants of Hold 6 in the aft section. The location of most of the contents of this container is not currently known.
d) Due to the position the wreck is lying on the Reef, with considerable intrusion of the Reef into the cargo holds, it is inevitable that further damage will occur to the Reef and the Reef environment if full wreck removal is undertaken.This includes physical damage to the Reef structure from the movement of cut sections, cutting chains, directional drilling or shaped explosives should those techniques be required.As the wreck is lifted or pulled from those areas where the wreck has embedded itself on to the Reef (Holds 5 and 6) further major damage to the Reef is likely to occur.
e)Whatever method is used to remove the wreck several different types and sizes of craft will be moored on and around the Reef.The anchors, chains and mooring lines will be dropped on and pulled across the Reef and the adjacent seabed. The moorings will cause damage to the Reef and its surrounding area.
f)There is already some contamination of Reef sediments by copper, TBT and PAHs. The Bioresearches report concludes that paint flakes from the Rena are likely to be the cause of elevated TBT in sediments. In addition, there are copper bolts, wire and other fragments that are contributing to elevated copper readings and PAHs from the oil spill following grounding.
http://www.renaproject.co.nz/resource-consent-application/video-proposal/
The wreck removal is technically difficult because of the shallow Reef, the offshore location, the deep water where part of the wreck is lying, the sloping wreck site, the broken up condition of the wreck and the prevailing open ocean weather conditions.
Wave statistics show that work cannot be undertaken for 52% of the time.This means that full wreck removal would be a very long operation (delayed by weather and the technical difficulty of the task), possibly up to 5 years.
Working at the Reef site is potentially hazardous. Three divers have already died on high profile wreck removal projects in 2014.Two diving incidents have occurred during the wreck reduction operations though fortunately neither resulted in serious injury to the divers involved.
COSTS
The total further cost for full wreck removal is estimated to be between US$425M and US$546M This is in addition to approximately US$300already spent to date on the salvage.
18 wrecks in the period 2002 to 20012 were compared with the Rena. It was the second most costly after the Costa Concordia)) The third most expensive case (i.e. after the RENA and the COSTA CONCORDIA) is reported to have cost just US$177.4M.
Based on a day rate of about US$261,000 per day and 1882 to 2588 days on site the operational cost would be in the range US$552 million to US$759 million.
Assessment of Environmental Effects (from the report by the Rena’s owner)
Physical aspects
Diver observations and sediment sampling show that despite the negative impact of the initial grounding, the natural character values of the Reef are being quickly restored. The marine life is as abundant as it was in the pre-Rena setting with a wide range of soft sediment plants and animals, marine invertebrates, pelagic fish species and mammals (especially NZ fur seals). Water quality and resulting underwater visibility continue to be of a high quality.
It is considered that leaving the wreck will not affect the physical structure of the Reef any more than what has already occurred from the grounding.
The Fisheries and Ecological Assessment says that the increase in habitat space and the structure of the wreck are likely to have a positive effect on the amount and diversity of biological communities and a minor positive effect on the fisheries.
Some members of the community (particularly recreational divers and commercial dive tour operators) have identified the Proposal as creating an opportunity to increase the value, for them, of the coastal marine area through the wreck becoming a dive attraction.
Any remaining floatable material (including polystyrene balls) that may be trapped within the wreckage might be released following significant storm events. Which happen in the Bay of Plenty. Floatable materials from the wreck will could be a navigational safety hazard for a short period.
Cultural Aspects
If the wreck is left there, this will mean they can remove the exclusion zone (the area where ships cannot go because of salvage work) early and it will provide positive economic benefits to the local boat charter tourism industry that previously visited the Astrolabe Reef area in regards to being able to return to the Reef sooner.
Wrecks such as the Rena have the potential to attract interest from wreck-diving enthusiasts who may travel some distance to visit the wreck, even as it breaks down. This brings benefits to the local economy as these visitors will need accommodation, food and supplies.