Notices to Mariners
The Danish Maritime Administration regularly sends out information about activities and projects in Danish and Greenlandic waters
Notices to Mariners
Notices to Mariners (NtM) operates with three categories:
-Preliminary notice (P)
-Temporary notice (T)
See descriptions of and examples of P- and T-notices below.
Updating of the table
The information in the table is updated daily at 05.00 AM.
Structure of the table
Notice - all active P-and T-notices from EfS are entered with reference to serial number.
Location / Activity - place and category of activity
Updated - the P or T message is promulgated as an update of the ENC
Affected ENC(s) - affected ENC(s)
Edition / Update - current edition and number of updates of affected ENC(s)
Categories of Notices to Mariners
Permanent notices provide information about changes of a permanent nature
1) Notification that a light has been moved in a port.
2) Notification that a wreck has been removed in a water area.
3) Notification that an anchorage area has been moved in a water area.
Preliminary notices - also referred to as P-notifications, where P stands for "Preliminary".
P-notifications provide advance notification about changes that are expected to occur in the near the future. The changes will often become permanent later.
1) Notification of the establishment of prohibited areas on a specified date in the future.
2) Notification that buoyage will be withdrawn on a specified date in the future.
3) Notice that in the a period in the near future cable laying will take place.
Temporary notices - also referred to as T-notifications, where T stands for "Temporary".
T-notifications provide information about changes of a temporary nature. The changes are not expected to be permanent.
1) Notification that a lighthouse is expected to be switched off for a stated period.
2) Notification that shallower depths have been observed in the approaches to a port.
3) Notification that a buoy is missing from its charted position.
Conversion of notices into ENC updates
Notices regarding permanent changes almost invariably lead to updating the ENC. There is a delay in the update if it is necessary for GST to obtain additional information and data from sources in the maritime community (owners, consultants and contractors involved in port extensions, cable laying, bridge construction, etc.). The acquisition of information and data in the correct format is sometimes time-consuming, which can result in a waiting period of several weeks before an ENC is updated.
Since the turn of the year 2022, GST has systematically evaluated P- and T-notices in NtM with a view to updating the ENC. The evaluation of the P- and T-notices is based on a number of criteria, see the decision tree below if necessary.
In general, notices on activities such as seabed surveys, geotechnical drilling or routine dredging does not lead to an update of the ENC. The activities are often spread over large areas in open waters. A display in ENC of these large areas will not give the shipping industry an accurate indication of where the activity is taking place at any given time. The ships involved in these activities carry lights and signals in accordance with the international rules of the sea. Navigators on other ships thus find it easy to recognize ships involved in these activities and pass them at an appropriate distance.
Delays in delivery of ENC updates
ENC is used by professional shipping in ships' electronic chart display and information systems (ECDIS).
Users of ECDIS may find that the display of, for example, a restricted area does not match a nitice in NtM regarding the establishment of this restricted area. The restricted area is typically created in connection with work at sea, where the contractor - after obtaining permission from the Danish Maritime Authority - lays out buoyage to mark where sailing is prohibited for a period of time. The problem stems from the fact that there are delays at several stages, from GST having made ENC updates to the same ENC updates being received on board the ships.
GST is part of an international collaboration regarding quality control and distribution. When GST creates updates for an ENC, they are sent to a "Regional ENC Coordination Centre" (RENC) located in England and called "IC-ENC" (International Center for Electronic Navigational Charts). It typically takes 3-4 days from GST updating the ENC to the release of the ENC updates.
Particularly problematic is the delay that many ships will experience in receiving ENC updates on board. It can take several weeks from the time GST releases ENC updates for distribution (via IC-ENC and their dealer network) until ships receive the ENC updates and can load them into ECDIS.
If a ship has not received the latest ENC updates that GST has released, the ship will therefore have to navigate on the basis of previous updates. If, for example, a restricted area is established in the period between the updates, you will not see it on ECDIS on the ship. This can lead to untoward incidents at sea.
GST seeks to reduce the delays in providing ENC updates by responding to the P-notices about the establishment of, for example, a restricted area, i.e. in the ENC code the notified location of the restrictive area with the start date as indicated in the P-notice.
An ENC update regarding the restricted area will thus be sent to the IC-ENC and released before the laying out of markings around the restrictive area has been carried out, but with a start date. This will basically ensure that if the ship receives the ENC update before this start date, the restricted area will be displayed correctly on ECDIS both before and after the start date.
However, the prerequisite for the restrictive areas to be displayed correctly on ECDIS before and after the start date is that the restricted area is established in accordance with the schedule laid out by the contractor (start date and location are as announced in the P-intelligence).
If the marks associated with a restricted area are not established in accordance with the contractor's schedule (typically postponed start date due to bad weather), ECDIS users will experience that the actual restricted area may differ from that displayed on the ECDIS.
Professional shipping must be aware that the problems with the long distribution time for ENC updates may mean that the seafarers, when sailing in the waters, risk experiencing a mismatch between what is seen on the ECDIS and what is seen from the ship.
Likewise, the uncertainty in relation to start dates in P-notices, and the related uncertainty in the ENC updates, can lead to a mismatch between what is seen on ECDIS and what is seen from the ship.
The information in the table reflects the decisions that GST takes after evaluating the P- and T-notices in NtM. As a result of the often long distribution time for ENC updates and the uncertainty in relation to the start and end dates in P- and T-notices respectively, navigators may find that the display on ECDIS does not agree with the information in the table.
GST decision tree