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How it works: Arrival estimation and destination changes
How it works: Arrival estimation and destination changes
Andy Hovey avatar
Written by Andy Hovey
Updated over a week ago

Arrival port and time are estimated for vessels to support planning and compliance monitoring and are available in the journey summary and track history for selected vessels. Changes to the destination, from self reported AIS data, are shown in the vessel's history.

The vessel list supports planning and prioritisation and provides information on; port of departure, the vessel’s journey, and the next port including arrival estimates.

How arrival estimation works

The estimated arrival port is determined using information from three sources (where available) in order of priority.

Source

Description

Displayed in app

Port schedule (only for New Zealand first arrival ports)

From a first arrivals port indicating a vessel arriving within seven days that has entered NZs 400nm.

Tauranga, New Zealand

Est. arrival window

Based on port schedule

Vessel movement (only for New Zealand first arrival ports)

Based on vessel velocity and shortest path to a first arrivals port. The shortest path is calculated using Dijkstra’s algorithm and a node network that covers water access routes. Only applies to sailing vessels that have entered NZs 400nm.

Tauranga, New Zealand

Est. arrival window

Based on vessel movement

Self reported AIS data

Destination matched to the corresponding UN/LOCODE where possible, and the most recent self reported date.

Tauranga, New Zealand (NZ TRG)

Est. arrival time

Self reported on time

What is self reported AIS destination data?

The International Maritime Organisation (IMO) guidelines advise a vessel’s crew to manually input their destination and ETA, as AIS voyage information, at the start of their voyage and whenever changes occur. It is recommended that the United Nations Code for Trade and Transport Location (UN/LOCODE) are used for the destination¹.

When the manually entered destination matches a UN/LOCODE the corresponding port name and country are displayed in Starboard and the information entered by the crew is placed inside brackets. When there is no match only the information entered by the crew is displayed.

AIS reported destination is voluntary and because it is manually entered it may be missing or incorrect for vessels. In some cases it may not be entered due to concerns over security or commercial sensitivity².

How it works: NZ first arrival ports

Port schedules

Port schedules are used when approval has been granted by a port manager. These schedules however are only an indication of the intention of a vessel to arrive and their accuracy is not guaranteed.

The estimated arrival time window

An arrival window is calculated with a 70% confidence of the vessel arriving within the window. For example, if a vessel is estimated to arrive in 24 hours the arrival window will show the vessel is due to arrive sometime in the next 18–30 hours.

As the arrival time nears the size of the arrival window is narrowed. For example, if a vessel is estimated to arrive in the next 4 hours the arrival window will show the vessel due to arrive sometime in the next 3–6 hours.

Table 1. List of first arrival ports used in estimation³

Region

Ports

Northland

Opua Marine Park
Marsden Cove Marina
Northport (Marsden Point Cargo Terminal)
Marsden Point Oil Refinery

Auckland

Bledisloe and Fergusson Terminals (freight)
Princes and Queens Wharf (passenger)
Chelsea Port, Birkenhead
Devonport (Royal New Zealand Naval Base)
Kauri Point, Birkenhead, (Royal New Zealand Navy)
Viaduct Marina
Silo Marina
Westhaven Marina

Tauranga

Port of Tauranga
Vessel Works Marine Precinct

Waikato (Taharoa)

Taharoa offshore buoy

Gisborne

Eastland Port

Napier

Napier Port

New Plymouth

Port Taranaki

Wellington

Wellington Harbour

Picton

Picton Harbour

Nelson

Port Nelson

Christchurch (Lyttelton)

Lyttelton Harbour

Timaru

Timaru Port

Dunedin (Port Chalmers)

Port Chalmers

Invercargill (Bluff and Tiwai Point)

Tiwai Point
South Port, Bluff

References

  1. International Maritime Organisation (IMO). (2015). Revised guidelines for the onboard operational use of shipborne Automatic Identification Systems (AIS). https://wwwcdn.imo.org/localresources/en/KnowledgeCentre/IndexofIMOResolutions/AssemblyDocuments/A.1106(29).pdf

  2. GreenVoyage2050 Project Coordination Unit. (2021). Ship-Port Interface Guide. International Maritime Organisation. https://wwwcdn.imo.org/localresources/en/MediaCentre/Documents/Ship-Port%20Interface%20Guide.pdf

  3. Ministry for Primary Industries. Places of first arrival – seaports. 2020; (12 September). Accessed 17 August 2021. https://www.mpi.govt.nz/resources-and-forms/registers-and-lists/places-of-first-arrival-seaports/

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