Chris Hoare - May 2005
know that about 80 percent of all crude oil imports to South
Africa, come through Durban's single buoy mooring (SBM)? Last
year that was 16,7 million tonnes.
some of the numbers involved and be impressed: a typical VLCC
(Very Large Crude Carrier) is worth about US$120 million,
has a deadweight of 300,000 tonnes and carries two million
barrels of crude oil worth US$100-110 million. It is 335 metres
long (that's three rugby fields) and 58 metres wide. Its draft
is 22 metres.
tanker has five decks and a bridge deck above the main deck,
and will have a top speed of 14-15 knots (about 25km/hr),
driven by a 35 000 horse power engine that is two-storeys
high; it burns heavy fuel; stopping distance is ten nautical
miles (16 km). Most tankers come to Durban with Iranian and
Saudi Arabian crude from the Arabian Gulf.
78 VLCCs called at the SBM which is anchored 2.6 km off Reunion
[on the Bluff], and has a 1.6 km exclusion zone around it.
The SBM is in 48 metres of water and is held in place by eight
seven-ton anchors, each on the end of 330 metres of chain
whose links are made from 90 mm diameter steel. The SBM is
owned by a consortium of oil companies.
by Chris Hoare, courtesy SAPREF
a SAPREF contractor, operates the SBM. When a tanker arrives,
five of their highly experienced men are taken on board by
helicopter. One is the ship's pilot who oversees the docking
process and monitors all the operations and the weather conditions
during discharge. Another is the discharge advisor, and the
other three are divers who couple the floating hoses to the
ship's discharge manifold and monitor the mooring hawsers
and hose connection throughout the discharge operation. They
are all also on standby to respond to any emergencies. Discharge
normally takes about 42 hours. Should weather conditions worsen,
the pilot takes the vessel off the SBM until the weather abates.
marine manager George Franklin, a master mariner with 38 years
marine experience, "We take the utmost care when discharging
oil at the SBM. Almost all tankers calling at the SBM are
modern double-hull vessels with separate ballast tanks, and
every vessel must be positively vetted by Shell Marine's rigorous
quality system before acceptance for any business. In SAPREF'S
offices at Bayhead we are able to monitor conditions at the
SBM including wind speed, pull on the mooring hawsers, swell
height, etc. We are also one of only a few operations in the
world having a full back-up team of divers on standby onshore,
and we have procedures and systems in place to ensure the
spill-free discharge of crude oil at the SBM within the hostile
environment in which we operate."