Notices to Mariners
The Danish Emergency Management Agency regularly sends out information about activities and projects in the Danish and Greenlandic waters.
Notices to Mariners
Notices to Mariners (NtMs) are issued in three categories:
-Permanent notice
-Preliminary notice (P)
-Temporary notice (T)
See descriptions and examples of P- and T-notices below.
Updating of the table
The information in the table is updated daily at 07.00 AM.
Structure of the table
Notice - all active P-and T-notices from the NtMs are presented with reference to a serial number.
Location / Activity - place and category of the activity
Updated - the P or T message is promulgated as an update of the ENC
Affected ENC(s) - the affected ENC(s)
Categories of Notices to Mariners
Permanent notices provide information about changes of a permanent nature.
Examples of permanent notices are respectively that:
1) a light has been moved in a port.
2) a wreck has been removed.
3) an anchorage area has been moved.
Preliminary notices - also referred to as P-notifications, where P stands for "Preliminary".
P-notifications provide notification in advance of changes that are expected to occur in the near future. The changes will often become permanent later on.
Examples of preliminary notices are respectively that:
1) a prohibited area is to be established on a specified date in the future.
2) buoyage will be withdrawn on a specified date in the future.
3) cable laying will take place within a period in the near future .
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.
Examples of temporary notices are respectively that:
1) a lighthouse is expected to be switched off for a stated period.
2) shallower depths have been observed in the harbour entrance.
3) buoyage is missing from its charted position.
Conversion of the notices into ENC updates
Notices regarding permanent changes almost invariably lead to updating of the ENC. There is a delay in the update if it is necessary for the GST to obtain additional information and data from sources within the maritime community such as 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, the GST has systematically evaluated P- and T-notices in the NtM with the purpose of 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 do not lead to an update of the ENC. These activities often take place in larger areas of open water. A display in the ENC of these larger areas will not provide the shipping industry with 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 of other ships thus find it easy to recognize ships involved in these activities and pass them at an appropriate distance.
Delays in the delivery of the ENC updates
The ENC are used by professional shipping in the Electronic Chart Display and Information System (ECDIS) of the respective vessel.
Users of the ECDIS may find that the display of for example a restricted area does not match a notice in the NtM, regarding the establishment of this restricted area. The restricted area is typically created in connection with work at sea. The contractor lays out buoyage to mark where sailing is prohibited for a period of time, after obtaining permission from the Danish Emergency Management Agency. The problem stems from the fact that there are delays at several stages, from the GST having made the ENC updates to the same ENC updates being received aboard the ships.
The GST is part of an international collaboration regarding quality control and distribution. When the 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 the GST has updated the ENC to the update of the ENC to be released.
Particularly problematic is the delay that many ships will experience in receiving the ENC updates aboard. It can take several weeks from the time that the GST releases the ENC updates for distribution (via IC-ENC and their dealer network) until the ships receive the ENC and thus are able to load them into their ECDIS.
If a ship has not received the latest ENC updates that the GST has released, the ship will therefore have to navigate on the basis of a previous update. If for example a restricted area is established in between two updates, it will not be displayed correctly on the ECDIS of the ship. This can lead to untoward incidents at sea.
The GST seeks to reduce the delays in providing the ENC updates by responding to the P-notices. The establishment of for example a restricted area will be coded in the ENC with the start date indicated in the P-notice.
An ENC update regarding the restricted area will thus be sent to the IC-ENC and released - with a start date - before markings around the restrictive area has been deployed. This basically ensure that if a vessel receives the ENC update before the 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 the ECDIS before and after the start date is that the restricted area is established in accordance with the schedule proclaimed by the contractor (start date and location are as announced in the P-notice).
If the marks associated with a restricted area are not established in accordance with the schedule of the contractor (typically postponed start date due to bad weather), users of ECDIS will experience that the actual restricted area may differ from that displayed on the ECDIS.
Summary
Professional shipping must be aware that the problems with the prolonged distribution time for ENC updates may cause the seafarers to experience 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 the ECDIS and what is seen from the ship.
Reservation
The information in the table reflects the decisions that the GST takes after evaluating the P- and T-notices in the NtMs. As a result of the often prolonged distribution time of the ENC updates and the uncertainty in relation to the start and end dates in the P- and T-notices respectively, navigators may find that the display on the ECDIS is not identical with the information in the table.
Decision tree
GST decision tree