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Improving Visibility and Precision at Sea

As modern LED technology provides lighting solutions that are brighter, more energy‑efficient and reliable, older navigation lights are swiftly becoming outdated. As a result, many mariners and harbour managers are upgrading, replacing or retrofitting marine navigation lights to improve lighting quality and prevent dangerous faults.


In December 2021, Hydrosphere upgraded the navigation lighting at Stornoway Harbour: the main port of the Hebrides and one of the best‑equipped harbours in northwest Scotland. For this project, Hydrosphere were tasked with replacing Sandwick Bay’s sector light, which indicates the entrance into the harbour on the Isle of Lewis.

The existing light was an ageing PEL 3 unit (a projector-style marine beacon) that proved difficult to see at night after many years of service. Situated 10 metres above sea level in the Battery area of Stornoway, the soft light had a slow flash rate. It was difficult for vessels entering the harbour to positively identify against the backscatter of bright lights from buildings, streets and moving traffic.

Hydrosphere was asked to recommend and install an upgrade. Previously, Hydrosphere supplied a VLS-46 precision sector light for Stornoway’s River Creed, which proved popular with the local ferry. Hydrosphere proposed fitting a VLS‑46 Ultra unit that provides sufficient intensity to be visible by day and outside harbour limits for Stornoway Harbour.

The VLS-46 is a high-powered LED light providing a cost‑effective solution where precise navigation is required or traditional leading marks are impractical. Like River Creed’s light, our team set its projectors to alternate between red, white and green to provide additional navigational information to users who find it intuitive.

The VLS-46 operates using minimum power consumption, which is a great benefit when using solar power. These particular sector lights also have turn- down capability at night, which allows them to be conspicuous but not intrusive, as can be the case with other products and lights using conventional lamps.


The VLS-46 precision light has dramatically improved visibility and clarity from the sea at Sandwick Bay. The light can now be seen from well outside the harbour entrance in daytime and nighttime and stands out powerfully against the background of rising ground and scattered surrounding lights.

The decision to include alternating red/ white and green/white sectors in the transition between the central white and the red and green side sectors offers a more precise indication of a vessel’s position. The team at Hydrosphere also took the opportunity to increase the Isophase (Iso) characteristic of the light from Iso 6s to a more rapid Iso 4s.

During alignment at night, it quickly became apparent that the new sector light was a significant and welcome improvement to the quality of navigation lighting at Stornoway Harbour.

Alasdair Smith, a pilot and assistant harbourmaster at Sandwick Bay, is delighted with the result. “It is instantly identifiable during pilotage, and the alternating sectors give more precision as to where a vessel is located within the white sector. We have had very positive feedback from the local ferry, commercial vessels, fishing vessels and yachts. The difference truly is remarkable.”

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