Harbour Operations point of contact: operations@cmassets.co.uk


Improving marine navigational safety in Oban Harbour

We are working in partnership with Argyll and Bute Council, Northern Lighthouse Board, CalMac Ferries Ltd and more recently Oban Community Harbour Development Association (OCHDA) to improve communications and navigational safety in Oban Harbour.

The project began in 2014 due to the increasing volume of ferries, commercial and marine leisure activity. Following the introduction of Road Equivalent Tariff (RET) on the Oban to Mull route there was a significant increase in ferry traffic navigating Oban Bay making the work of with the partnership even more relevant.

We are delighted that the hard work and continued engagement with all the stakeholders has delivered progress towards improving navigational safety in Oban Harbour and we are looking forward to continuing ongoing improvements in the harbour environment and particularly the work of OCHDA.

OCHDA was established in 2019 to support the development of alternative harbour management arrangements for Oban Bay through the establishment of a Trust Port as a new Statutory Harbour Authority to cover the currently un-managed waters that lie beyond the exisiting statutory harbour areas of CMAL and Argyll and Bute Council.

To date the partnership working has so far successfully delivered:

  • A fully operational Oban Harbour website
  • Introduction of VHF 12 as a harbour working channel channel
  • Single point of contact
  • Seasonal motoring advisory and guidance for small craft
  • Helicopter guidance
  • Full review and revision of navigational aids review of anchorages
  • Regular key stakeholder meetings and ongoing engagement
  • Annual review of navigational risk assessments

The Single Point of Contact provided jointly by Argyll and Bute Council’s harbour staff at the Council owned North Pier, and CalMac Ferries’ pier and terminal staff operating at the Railway Pier, continues to be the focus for assistance to harbour users.

Information signs erected at prominent points around the harbour provide basic safety and navigational information to assist harbour users and the public.

Further work is planned for joint emergency planning and exercises, towage evaluation, extended CCTV, and local port service’s needs.


Information regarding harbour CCTV installation that commenced on February 2016 can be downloaded here (PDF, 61kb).


As a harbour authority CMAL has a duty to conserve its ports and harbours and a duty of reasonable care to ensure the safety of navigation within its jurisdiction.

Harbour authorities should provide users of the harbour with enough information about conditions in the harbour such as depths of water, local Notices to Mariners, etc. and have duties and powers as local lighthouse authorities (or providers of aids to navigation); and specific powers in relation to wrecks.


Harbour authorities have a duty to find, mark and monitor the best navigable channel or channels in the harbour. A statement of the measures adopted should be included in the published policies and plans. Effective arrangements to publish appropriate hydrographic information (charts, warnings about recent navigational hazards) must also be in place.

CMAL maintains a schedule of routine annual hydrographic surveys undertaken by its contractor Aspect Surveys Ltd that over a 5-year period encompass all ports, harbours and other geographical areas where they have responsibilities throughout the Clyde and west coast.

The UK Hydrographic Office (UKHO) is responsible for compiling and publishing charts for all tidal waters around the UK, together with the Admiralty Sailing Directions and CMAL provides the UKHO with the results of all their surveys.

Aids to Navigation (AtoN)

As a local lighthouse authority (LLA) CMAL is required through UK commitment to SOLAS to operate in accordance with International recommendation and guidelines. For marine Aids to Navigation the standards are set by the International Association of Marine Aids to Navigation and Lighthouse Authorities (IALA).

The method of measuring Aids to Navigation and the recognised availability standards are set for each category of Aid by IALA. These are published in the IALA Aids to Navigation Guide.

IALA states that the absolute minimum level of operational availability for individual aids to navigation is 95%. If availability of an individual Aid falls below this level then consideration must be given to withdrawing the Aid to Navigation from service.

The availability of the actual Aid to Navigation (e.g. whether the light is flashing correctly or a buoy is on station) is over a 3-year continuous period. High levels of availability, which match or exceed internationally recognised standards, ensures that CMAL provides the service required by mariners in our hostile marine environment.

Categories of AtoNs

Each of the Aids to Navigation operated by CMAL is allocated an IALA category as follows:

Category 1
An Aid to Navigation that is considered by CMAL and the Northern Lighthouse Board to be of primary navigational significance. It includes the lighted aids to navigation that are considered essential for marking landfalls and primary routes.

Category 2
An Aid to Navigation that is considered by CMAL and the Northern Lighthouse to be of navigational significance. It includes lighted aids to navigation that mark secondary routes and those used to supplement the marking of primary routes.

Category 3
An Aid to Navigation that is considered by CMAL and the Northern Lighthouse to be of less navigational significance than Category 1 and 2.


AtoN Availability by Category

IALA Category No of Aids Total Hours No of Failures Availability Target Availability
CAT 1 5 131,400 1 99.97% 99.80%
CAT 2 54 1,414,200 5 99.79% 99.00%
CAT 3 11 194,328 0 100.00% 97.00%
No Category 0 0 0 0.00% 0.00%
Totals 70

Date Range from 01/04/2021 to 31/03/2024

How Performance is measured

Availability is measured by dividing total time (i.e. the sum of the total number of hours in a year multiplied by the number of Aids to Navigation in each category) into the difference between total time and the number of hours that the Aids were not available to the mariner. This calculation is then expressed as a percentage.


CMAL is constantly looking for new ways to provide increased levels of information for mariners using our ports and harbours that will further enhance navigational safety and efficiency. To that end, CMAL has engaged with Hydrosphere Ltd and Aqua Power Technologies to put together a newly developed and cost-effective wave monitoring system. It is anticipated in the coming months the first buoy will be deployed near to Brodick Ferry Terminal to assess its capabilities and reliability before being considered for deployment at some other CMAL harbours.