DCN October Edition 2019

local barge sourced by the Southern Phoenix’s owners. Local tug
assistance was also provided.
Whilst these works were progressing, engineering works were
underway to allow salvors to set up and cut through the crane
pedestals using diamond wire sawing. Additional equipment to
chain cut the superstructure and funnel were also set up.
Removal of the cargo hatches required divers to work in close
collaboration with deck and crane crew. The divers worked down
to 17 metres in limited to zero visibility. The hatch covers were
removed onto the seabed to allow them to act as ‘landing skids’
for removal of the cargo in the hold. They were later recovered and
delivered to the vessel’s owners for disposal.
Two 12-tonne deck-mounted winches were utilised to drag the
containers onto the hatch covers, allowing them to be recovered
by a straight lift from the crane. The cargo within the hold was
in disarray due the concrete modules and power poles having lost
their lashings.
HOW THE PROJECT UNFOLDED
By January 2018 the hold had been cleared of all cargo which was
consolidated ashore. The emphasis was then on the removal of
both pedestal cranes which were set into the seabed. The cutting
of them using a diamond wire went well and the cranes settled on
the seabed, allowing them to be individually picked up below the
barge and lashed using 150-tonne Dyneema grommets. The cranes
were then taken to a designated dumping ground beyond the 1000-
metre contour where they were released via use of explosive cutters
to the grommets.
After disposal of the cranes, the superstructure and funnel
were cut using a more traditional chain cutting process. Dyneema
grommets and explosive cutters were once again used, allowing for
a controlled release in the designated dumping ground.
Prior to parbuckling, all of the fuel tanks that had contained
hydrocarbons, were again stripped out to eliminate the risk of
any pollution.
The remnant hull lying on its port side was then prepared for
parbuckling and re-floating. Considerable naval architectural
modelling revealed that it would be best to parbuckle the hull
upside down and to re-float it in this mode.
The modelling, conducted by Glanvilles Naval Architects in
Cairns, identified a greater degree of stability in this mode due to
the hold being a full-length hold, and that to re-float upright would
create too many free surface issues. Fittings were installed on
the hull and also internally in the holds into DB tanks to assist
the parbuckling.
On March 12, the hull was successfully parbuckled and
settled on the seabed at a depth of 11 metres.
On April 16, the hull was re-floated and multiple leaks
identified including the stern seal, engine room plating and fore
peak. Considering that the ship had been submerged for almost
two years these leaks were not unexpected.
After conducting hull repairs it was ready for final re-floating
and towing to the dumping ground. This stage in the project
was dictated by available weather windows to allow for the hull
to be towed upside down whilst being maintained in a stable
condition with air feeds to ballast tanks, DB tanks, engine room
and the fore peak. The hold was fitted with six vents to prevent the
accumulation of excess air, resulting in a destabilising longitudinal
free surface effect.
On May 25, the hull was slowly towed from Suva Harbour to
the designated dumping location 9 NM from Kings Wharf. The
tow and disposal went as planned and the Southern Phoenix was
successfully sunk in 1000 metres of water with no pollutant release
or untoward incidents. There were no safety issues, including lost
time injuries, associated with the project.
Pacific Towing services Oceania as well as South East Asia and is
a full member of the International Salvage Union.
Pacific Towing designed an ingenious
and low-cost wreck removal solution
whereby the Southern Phoenix was
re-floated and towed upside down to
its final dumping ground
Pacific Towing
Salvage equipment including a barge
and crane were mobilised from Papua
New Guinea, Australia and Singapore
for the wreck removal project
The project necessitated 1,183 dives resulting in over 1,000 hours
bottom time. There were zero safety issues and LTIs
thedcn.com.au October 2019 47