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More than 300 fully laden super tankers pass the southern coast of Sri Lanka each
month, exposing the country to potentially major oil spill disasters that would
have a disastrous effect on both the tourist beaches of the island and the expanding
fishing industry. Colombo Port, operated by Sri Lanka Ports Authority (SLPA), together
with the new privately owned container terminal currently under construction, handles
in excess of 3000 ships a year. For a country with such a strategic position on
world shipping routes great opportunity exists to increase the handling of transit
cargo. Consequently, with this in mind, in 1998 with the backing of the Swedish
International Development Agency (SIDA), the SLPA entered into a contract with Pharos
Marine, the world leader in maritime aids to navigation, to improve the standard
of its navigational aids.
The project comprised two elements:
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Rehabilitation of the existing lighthouses on the southern coast to comply with
IMO and IALA minimum recommendations for Marine Aids to Navigation.
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Installation of a networked DGPS Beacon System.
Over the past few years the Sri Lankan government has been investing heavily in
improving the fishing infrastructure of the Southern District. With few of the native
fishing boats having electronic navigation systems, they are dependent on the effectiveness
of land based lighthouses for night fishing.
During the course of the 1-year project Pharos Marine has rehabilitated 5 lighthouses
on the southern coast: Dondra Head, Barberyn, Great and Little Basses and Galle.
With the exception of Galle all were designed by James Douglass and constructed
by William Douglass of the Imperial Lighthouse Service in the latter part of the
19th century. The quarries of Dalbeattie in Scotland and Penryn in Cornwall supplied
the granite rock used in their construction. During the last century the mode of
illumination has changed from coconut oil to gas to the present day electrical system
installed by AGA/Pharos Marine in the late 1960's.
Galle lighthouse was constructed by the Ministry of Public Works in 1939 after the
original 1840's structure was damaged by fire in 1933. The existing system employed
a Chance Brothers glass prism lens floating on a bath of mercury to reduce friction
and rotated by a weight driven machine that had to be rewound every few hours.
After the initial project survey and discussions with the SLPA, it was decided that
the existing Pharos Marine PRB-21 sealed beam optic and drive pedestal at Dondra
Head, Barberyn, Great and Little Basses were still in excellent condition after
30 years of trouble free service and would not be replaced. Over 300 lighthouses
worldwide are installed with a PRB series revolving pedestal. Its gearless drive
system, which employs no brushes or contacts, means that it is ideally suited to
high moisture and saline atmospheres with only infrequent and simple maintenance
required.
The existing pedestal control equipment, however, was obsolete and was replaced
by a Pharos Marine PRB-21 Control Unit which uses a PLC to monitor and control every
aspect of the pedestal and lamp array. The unit is fully automated to enable the
switching between the Main AC sealed beam lamp array and the standby DC battery
operated Emergency lantern.
It was essential that not only the primary lighthouse equipment but also the secondary
equipment were fully upgraded. At Barberyn Lighthouse a new Lister- Petter TR4 triplicate
generator set was installed.
Galle lighthouse is situated on the ramparts of the old Dutch Fort overlooking the
seaward channel into Galle harbour. It was suspected that old tunnels dating from
the Dutch occupation of the fort still ran underneath the ground in the locality
of the lighthouse. The deployment of cranes into the area was, therefore considered
too dangerous and so all old and new equipment had to be lifted through the lantern
house door using a block and tackle.
The existing Chance Brothers 4th order glass optic was still in excellent condition
and was re-used on the new installation. For the new light a Pharos Marine PRB-20
system was employed. This consists of the existing optic mounted on a PRB series
gearless drive pedestal and a Pharos Marine 2-place UVLA lamp-changer. For both
the main and reserve lamp an OSRAM 250W HQI-T metal halide was used providing an
effective intensity of 950,000 cd's.
At each of the 5 lighthouses a Pharos Marine Phalcon-3 Radar Responder Beacon (Racon)
and a Pharos Marine FA-250 were mounted on the lantern house gallery handrail. Each
emergency lantern was fitted with a 3A lamp located in an APCL-5 flashchanger, producing
a visible range in excess of 9 nautical miles. An acrylic selfcleaning lens cover
was fitted to the exterior of the lantern to prevent the build up of salt on the
lens during the south-west monsoon from April to October.
In order to provide prompt and accurate data to the mariner and to help the SLPAs
Harbour Masters Section in their fault diagnosis, each of the lighthouses were linked
on a radio monitoring system, using radio equipment provided by Meteor Communications
Corporation (MCC), back to the Central Control Office in Colombo Port Pilot Station.
The system used Pharos Marines standard Data Acquisition Unit (DAU) connected to
an MCC-545A radio modem, operating in extended line of site (ELOS) mode. The advance
signal processing techniques employed within the MCC- 545A to relay the packet telemetry
data enables the unit to transmit at more than 100W off a single 100Ahr battery.
The network was set up in such a way that if any node on the relay network failed
the data would locate another node through which to route its telemetry data back
to the Central Control Office. At the monitoring office lighthouse status information
on the main lamp, rotation speed, emergency lamp, racon etc were displayed on a
standard desk top computer running MCC Data Monitoring Control Software.
To provide dual DGPS coverage along the south-western coast, 3 DGPS Radio Beacon
Systems were installed by Pharos Marine in the Port of Colombo, Barberyn and Dondra
Head Lighthouses. As Barberyn and Dondra Head are popular tourist locations all
installations were sympathetic to the environment whilst ensuring optimum performance
and safety of the system.
Each site installation had identical equipment, namely a Pharos Marine MRB-715 Radio
Beacon and Trimble Reference Stations and Integrity Monitors. Reliability of the
system was further improved by having a redundant radio transmitter, Reference Station
and Integrity Monitor so that in the event of a transmitter or reference station
fault the system would automatically switch over to the other unit.
Each site installation had identical equipment, namely a Pharos Marine MRB-715 Radio
Beacon and Trimble Reference Stations and Integrity Monitors. Reliability of the
system was further improved by having a redundant radio transmitter, Reference Station
and Integrity Monitor so that in the event of a transmitter or reference station
fault the system would automatically switch over to the other unit.
This project was the first stage of the SLPA's program to modernise its aids to
navigations. Future projects are likely to include the rehabilitation of Colombo
Lighthouse, upgrade of the Great and Little Basses power system and the eventual
rehabilitation of the lighthouses in the north of the country.
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