DEPTH IN METRES Reduced to Chart Datum, which is Approximate ALAT (Approximate Lowest Astronomical Tide) HEIGHTS IN METRES Drying heights are above Chart Datum Other heights are above Mean Sea Level Vertical clearances are above HAT (Highest Astronomical Tide) VESSEL REPORTING For details of the Nieuwe Waterweg Vessel Traffic Service see the Netherlands Coast Pilot (HP1) or Admiralty List of Radio Signals. DEPTHS AND AIDS TO NAVIGATION The channels and depths shown on this chart are subject to frequent change. The buoyage and other aids to navigation are adjusted accordingly. For the latest information see Notices to Mariners or consult the pilotage authorities. DEPTHS IN HARBOURS Depths in harbours and along quays are maintained by dredging. For the latest information consult the pilot. SUBMARINE CABLES AND PIPELINES Matiners are advised not to anchor or trawl in the vicinity of submarine cables and pipelines. Pipelines are not always buried and their presence may significantly reduce the charted depth. They may also span seabed undulations and cause fishing gear to become more irrecoverably snagged, putting a vessel in severe danger. PORT SIGNPOSTING SYSTEM Berth numbers e.g. 6001-6105 relate to the Port Signposting system. These numbers correspond to the numbering of the waterfront. The port numbers are indicated in black figures on yellow boards.