- Brief Overview
- The Project
- The Sussex Marine Trust
- Socio-Economic Impact
- Environmental Impact
- Contact Us
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Initial Preparation: Soon after acquisition, the vessel may need to be dry docked so that the sonar dome on the keel and its contents can be removed as the Ministry of Defence wish to retain this equipment. Dry Docking a ship of this size is likely to cost in the region of £270,000.
While in dry dock the propellers can be removed. If the vessel does not require dry docking for the removal of sonar equipment, then any keel equipment removal and propeller work can be done by commercial divers, the expected cost of this is likely to be £20,000.
All the oils and lubricants associated with the propeller shaft running and water sealing system will be drained.
The propeller shafts will be welded and sealed with a non-polluting system to ensure it remains water tight during the remaining towing operations and full cleaning process.
Full Cleaning Process: After towing to its final port the ship will be moored for the full cleaning to be conducted.
All hydrocarbons (fuels, oils and lubricants) will be drained and disposed of. Any hydrocarbon 'dregs' will be soaked up using a suitable absorbent material, allowing this remaining pollutant to be gathered and disposed of through an approved disposal route. All fuel/oil tanks will be steam cleaned to remove all residues.
All electrical cabling will be removed as the insulation often contains PCB's and other potential marine pollutants. If left in place this cabling and cable trays will, over time, come adrift from their fixings and will create an entanglement hazard for divers visiting the reef, so they have to be removed.
Pipes and other potential entanglement hazards will be removed, along with various bulkheads to create clear routes through the structure for visiting divers.
Diver access holes will be cut in the hull at the level immediately below the main deck.
Additional diver access holes will be partially cut above, but near the waterline, with the corners remaining uncut. These cuts will be filled with commercial sealant to prevent water ingress from wave action during the final towing and positioning activities. The corners will be cut as part of the explosive scuttling sequence, in order to open these holes.
Scuttling/Diver Access hole locations will be prepared below the water line, so that the explosives can be fitted into these positions prior to scuttling.
Other smaller scuttling hole locations will also be prepared, these are designed to be too small for diver access and will be used to flood areas that divers are not permitted to explore (tight spaces, potential entanglement sites, etc.)
The final cleaning operation will be high pressure water jetting to wash all residues generated from the various cutting processes, down into the bilges from where they will be pumped out for appropriate disposal.
This should leave the vessel in a completely virgin state, clear from all potential marine pollutants and ready for colonisation by marine organisms as soon as it hits the sea bed.
If all of this cleaning work were to take place in a dry dock it would cost in the region of £2,175,000.
If the cleaning operations can be conducted while the ship is floating alongside a suitable salvage facility it could be achieved for approximately £185,000 – considerably less than one tenth the cost of doing the work in dry dock.
For this reason two ports with salvage yards have been identified and are being investigated:
The preferred option is Newhaven as it is the closest port to the proposed scuttling site (figure 7).
The alternate port for the cleaning work is Shoreham harbour (figures 8).