Sealite Marine Lanterns Modernise Sark Lighthouse

“The lighthouse is fully operational at present. We expect the light station to get a further 20 years of reliable operation, enhancing safety for mariners in the area.”

– Trinity House Programme Manager, Steve Keddie

Background

The Channel Island archipelago is situated off the northwest coast of France and consists of four main islands, interspersed with eight small, uninhabitable islands in the English Channel. The island chain is surrounded by islets and rocks which litter the dangerous-but-navigable waterways. Currents of up to 12 knots, combined with frequent poor visibility and foul weather, make navigation in the Channel Islands a challenge.

Sark, one of the smaller inhabited islands, covers approximately 2 square miles/5.4km. It is connected to other islands in the archipelago by ferry and is car-free; tractors and horse-drawn carriages are the only permissible vehicles. Sark enjoys the distinction of being designated as a Dark Sky Community, adopting ordinances to help alleviate wildlife sensitivity to artificial light at night. With its rugged natural beauty and steep rocky coastline, Sark is a natural attraction for tourists and sailors alike.

The first lighthouse (Sark) on the tiny island was constructed in 1913 by Trinity House. Its stone construction ensured it would weather the rough, Channel Island environment. Made entirely of stone and poised on top of the Blanchard Rock pinnacle, it aids vessels as they navigate through the treacherous waterways of the Channel Islands.

Challenge

Access to Sark Lighthouse is extremely challenging, with access being only via a flight of steps from the top of the cliff. The lighthouse is attached to the steep face of the cliff which rises high above it, while the steep rocky nature of the coastline lies below. Due to the challenging and dangerous terrain, maintenance of the lighthouse proved difficult and time-consuming.

Though automated in 1994, Sark lighthouse required an extensive amount of power to turn the two-ton rotating optic, making it extremely inefficient to operate. Additionally, the light rotated on a hazardous mercury bath, posing a potential health risk to lighthouse staff. Frequent repairs and new navigational requirements established the need to upgrade the lighthouse station system and modernize the optic.

Solution

Two Sealite SL-300 LED marine lanterns were selected by Trinity House (a UK based charity which acts as a General Lighthouse Authority) to replace the old rotating optic. The two LED lanterns are positioned one above the other to provide the main light and a standby light arrangement, whilst both achieving the navigational requirements. With a range of up to 21NM, the SL-300 long-range lanterns can be adjusted to over 90,000cd per lantern, providing a high intensity, two-tier light source for the Sark lighthouse. A decrease in required maintenance, along with the high efficiency of the new lanterns provided, huge cost savings were seen by Trinity House.

The unique LED design and size of the lights present significant advantages over larger assemblies and enable the efficient running of the lighthouse, whilst maintaining the effective range for the safety of mariners. The full re-engineering of the lighthouse saw the electronics upgraded along with the light source for a full lighthouse solution. The re-engineered Sark lighthouse is now more economical and achieves reliable operation for Trinity House and will for many years.