ENCs are used by professional shipping in ships' electronic chart display and information systems (ECDIS).
The Geodata Agency (GST) will update the ENCs covering the Fehmarn Belt as the work areas are adjusted and moved. As there are frequent adjustments and relocations, the professional shipping will receive many ENC updates.
Users of ECDIS with associated ENC may experience that the location of the work areas in the ENCs do not match the real location of the work areas. There are two reasons for that problem.
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.
The problem also stems from the fact that GST must carry out the ENC update on the basis of the plans for the work areas that GST continuously receives from the contractor via the client Femern A/S. There are uncertainties in relation to the start time and duration of relocations of the work areas in these plans.
Delays in delivery of ENC updates
GST is part of an international collaboration regarding quality control and distribution. When GST has made ENC updates, they are sent to a "Regional ENC Coordination Center" (RENC) located in England and called "IC-ENC" (International Center for Electronic Navigational Charts).
It is the routine in IC-ENC that preparation of data sets with all ENC updates is done on Thursdays and on Fridays the ENC updates are distributed to the network of ENC distributors. GST adapts to that routine by sending ENC updates for validation at IC-ENC on Tuesdays. After validation, the GST formally authorizes the IC-ENC to distribute relevant ENC updates (ENC Update Release).
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 update of the ENC covering the Fehmarn Belt, which GST has released, the ship will therefore have to navigate through the work areas on the basis of the previous update of the ENC covering the belt. If the location of a work area is adjusted or moved in the period between updates, you will experience on the ship that the real location of the work areas does not match the location of the work areas in the ENC.
Update on the basis of plans for work areas
GST receives plans for work areas from the contractor via the client Femern A/S every week. In the plan, the contractor gives an estimate of the expected adjustments and relocations of the work areas 5 weeks ahead.
GST will seek to address the delays in providing ENC updates by responding to these plans ie. in ENC, code the notified location of the work areas with the start date as indicated in the plans.
Thus, ENC updates regarding the work areas will be sent to IC-ENC and released before adjustments and moves are made, but with a start date. This will basically ensure that if the ENC update is received on the ship before this start date, the location of work areas will be shown correctly on ECDIS both before and after the start date.
However, the prerequisite for work areas to be displayed correctly on ECDIS before and after the start date is that the contractor adjusts or moves the work areas in accordance with the plans (start date and location are as notified).
If the contractor does not adjust or move a work area according to the plan (typically delayed start date due to bad weather), ECDIS users will experience that work areas are not displayed correctly on ECDIS.
Professional shipping must be aware that the problems with the long distribution time for ENC updates may mean that the seafarers, when sailing through the Fehmarn Belt, risk experiencing a mismatch between the location of the work areas in ECDIS and the real location of the work areas.
Likewise, the uncertainty in relation to start dates in the contractor's plans, and the associated uncertainty in the ENC updates, can lead to a mismatch between the location of the work areas in ECDIS and the real location of the work areas.
By inquiry on VHF channels 68, 09 and 16, VTS Fehmarnbelt can inform about how the work areas must be passed.