Notice to Mariners : Mcarthurs head

Mariners are advised that, on or about 24 FEBRUARY 2005, the white tower will be partly obscured by scaffolding and GREEN sheeting and will appear less well defined due to essential engineering works.

These works are scheduled to complete in June 2005. A further Notice to Mariners will be issued when the appearance of the Lighthouse Tower is restored.

This Notice to Mariners is part of NLB refurbishment programme which has been ongoing since 1998 and will be complete by 2004 for replacement of Acetylene and Propane gas systems with solar electric energy. Eight primary battery powered lights will be solar powered by 2005, giving a total of 120 solar powered lights. Sixteen other diesel powered sites will be progressively converted to solar powered operation.

The characteristics of the gas light will be emulated by the new electric lantern and will, where appropriate, include the retention of coloured sector arrangements. However, during the construction phase it is very often necessary to use temporary lights of lower range due to power supply restrictions and which also do not provide sector marking.

NLB have operated gas powered systems for more than 100 years and these were the first automatic lights in Scotland. In general these were installed where a low range, eg less than 10 miles was required. A local attendant ensured that the gas supply was available and illuminated and that the gas mantle was in good condition. The structure or building (not a traditional lighthouse tower but a small brick building or cast iron cylinder) was regularly painted. An annual gas delivery by NLB tender was necessary. Today these structures can be replaced with low maintenance aluminium towers and eco friendly solar electric power for the electric lights. Such lights have been operated by NLB since 1985 and have been used in buoys since 1993. There are currently 88 NLB solar powered land based sites from Holm of Skaw at the north tip of the Shetland Isles to Chicken Rock at the south end of Isle of Man in addition to some 105 floating solar systems all around the coastline. The range of light varies between 3 miles and 23 miles. Lights of less than 15 miles are normally tungsten lamps exhibiting the advertised character by using electronically controlled flashers switching the lamp on and off.

NLB’s first automatic long range lights were also powered by acetylene gas and were first installed in the early 1960s. Lens systems mounted on a turntable rotated using the gas pressure from the acetylene gas cylinders, were installed in traditional lighthouse towers. A sun-sensitive gas valve controlled the supply to the gas mantle, allowing economic use of the available gas. Nevertheless, an annual supply trip by NLB tender was necessary.

Development of high efficiency metal halide lamps has allowed the replacement of the gas mantle to be achieved using solar-electric systems which charge batteries by generating an electric current directly from sunlight. In the northern latitudes of Scotland and Isle of Man, the solar panels can make use of the diffused light through the cloud cover and the battery is of a size to accumulate sufficient energy in the summer and autumn months to ensure winter operation. The power consumption for the typically required light range of 18 miles has decreased in the last decade from over 100 watts to 35 watts making use of highly efficient lamp drivers operating directly from the 24 volt battery supply. Supplementary power for monitoring purposes is supplied from small wind powered generators.

To ensure that all Aids to Navigation operate correctly, NLB aim to monitor the performance by using land line and cellular telephone or radio links connecting the light to NLB monitor centre in Edinburgh. Any resulting malfunction can be immediately advertised to marine users using the Internet or maritime information systems.

NOTICE TO MARINERS

(No 8 of 2005)