Northern Lighthouse Board
Notice to Mariners, 8 January, 2020

DGPS is provided as a marine aid to navigation, giving all year round service with overlapping signal coverage up to 50 nautical miles around the coasts of the United Kingdom and Republic of Ireland. The signal provides the mariner using a suitable receiver with both real time integrity monitoring of GPS derived positions and the capability of fixing their positions to better than 5 metres (95% probability) in moving applications. Greater accuracy can be achieved in stationary applications.

All mariners are advised:

1. DGPS relies inherently on GPS, the operation and characteristics of which is under the control of the US Department of Defense. Users are cautioned that the signal availability and accuracy may be subject to change without warning.

2. The DGPS service is provided primarily for use in monitoring the integrity of GPS to enhance the safety of marine navigation. The provision of greater accuracy for marine navigation is a secondary feature.

3. Signal reception may become unreliable, under certain extreme environmental conditions, towards the limits of the geographical coverage.

4. All radio navigation systems are susceptible to interference (including jamming) and environmental effects, which can adversely affect their availability. The GLAs strongly advise that no single aid to navigation system should be used in isolation and that DGPS users should use all alternative means available to cross check the information received. Users should also ensure that they have a receiver which gives sufficient warning of the complete loss of the DGPS signal and reversion to GPS.

5. Various DGPS receiver types are available, some of which may not provide appropriate or timely warnings in respect of the system.

6. Reference should also be made to Volume 2 of the Admiralty List of Radio Signals. In particular, mariners’ attention is drawn to the section dealing with horizontal datums on charts and satellite-derived position notes.

M P BULLOCK
Chief Executive

Northern Lighthouse Board
Notice to Mariners, 8 January, 2020

Northern Lighthouse Board advise that the following Notices to Mariners from previous years remain in force:

10/2018 – Mull of Kintyre – Temporary Light
12/2018 – Stroma (Swilkie Point) – Temporary Light
17/2019 – Butt of Lewis – Temporary Light

M P BULLOCK
Chief Executive

Northern Lighthouse Board
Notice to Mariners, 8 January, 2020

Northern Lighthouse Board request Mariners navigating around our coasts to exercise the greatest care to avoid damage to floating Aids to Navigation.

Mariners should give all navigational buoys a wide berth, always having regard for the strength of the wind and tide, and are requested to report immediately any defect in any Aid to Navigation either to NLB’s Monitoring Centre (telephone 0131 473 3198), or to HM Coastguard.

The Merchant Shipping Act 1995 makes provision for the imposition of a fine on any person who wilfully or negligently runs foul of, or makes fast to, any Lighthouse, Buoy or Beacon, and for the recovery of the expenses for making good any resulting damage.

Northern Lighthouse Board operates a number of lighthouses with adjacent boat landings. Since the departure of lightkeepers from these sites, the landings are no longer maintained and we accept no liability for injuries or damage caused by unauthorised access to these sites.

Mariners are invited to contact the Navigation Section, Northern Lighthouse Board (navigation@nlb.org.uk), to comment on any aspect of the Aids to Navigation Service or on hazards to navigation around our coasts.

M P BULLOCK
Chief Executive