ADMIRALTY Vector Chart Service and ADMIRALTY Information Overlay - User Guide

ADMIRALTY Vector Chart Service (AVCS)

Overview

ADMIRALTY Vector Chart Service (AVCS) is produced and distributed according to well-defined international standards. This guide provides generic information to assist in managing and maintaining your AVCS holdings. It should be used in conjunction with the User Manual supplied by your ECDIS manufacturer. AVCS brings together official Electronic Navigational Charts (ENC) from national Hydrographic offices worldwide, including ENC coverage produced by UKHO in cooperation with Foreign Governments to provide comprehensive worldwide coverage.

Quality

AVCS meets customer requirements for a comprehensive, world-wide, fully carriage-compliant electronic chart service. It continues to develop in response to customer feedback. UKHO assesses ENC content against relevant paper charts, communicating any navigationally significant differences to users via ADMIRALTY Information Overlay (AIO). No other electronic chart service offers this level of reassurance.

Carriage Compliance

AVCS contains Official ENC data that meets Safety of Life at Sea (SOLAS) Carriage Requirements for use within Electronic Chart Display and Information Systems (ECDIS).

Licensing

ENCs in AVCS are provided under a license agreement for defined periods. AVCS Folios and ENC Units can be added to an AVCS license at any time for 3, 6, 9, or 12 months, offering flexibility to match chart holdings to operational patterns.

SENC Services

When loaded into ECDIS, ENCs are converted to the System ENC (SENC) format. Some service providers convert AVCS ENCs to SENC ashore for more efficient loading, sending them to the vessel, usually by download. AVCS SENC services carry full ADMIRALTY assurance and accreditation.

Pay as you Sail (PAYS)

PAYS subscriptions provide permits for most of the AVCS portfolio for voyage planning. If the Producer allows their ENCs in the PAYS Service, individual purchase is avoided. Users are charged only when their vessel tracks across the coverage of each ENC. ENC data must still be loaded onto the ECDIS manually or automatically.

Further Information

NP231 ADMIRALTY Guide to the Practical Use of ENCs is a comprehensive guide to ENC portrayal, standards, and regulations. The UKHO website, admiralty.co.uk, provides more information and resources for AVCS.

Getting Started with AVCS

This start-up guide helps you load and maintain AVCS data easily and quickly, describing basic steps for use in any ECDIS. Functionality may differ between ECDIS, so this guide should be used with your ECDIS manufacturer's User Manual. AVCS contains official ENCs issued by Government Hydrographic Offices and is designed for use with type-approved ECDIS to meet SOLAS Chapter V requirements.

Before You Start

Your ADMIRALTY Distributor will provide:

• A set of ENC Permit files (PERMIT.TXT and ENC.PMT) for each ECDIS equipment.
• 'Schedule A' Order Report (listing units added to your license).
• Access to AVCS ENC base and update data (via download or physical media).
• AVCS Certificate (showing vessel and license details).
• ADMIRALTY Information Overlay (AIO) data (recommended).

Refer to your ECDIS User Guide to remove any existing ENCs and installed permits. You are now ready to load AVCS onto your ECDIS.

Installing Permits and Data

Specific instructions for common ECDIS models are available at admiralty.co.uk/AVCS. Videos are also available at youtube.com/user/AdmiraltyTV.

1. Before loading AVCS ENCs, install the ENC Permits (ENC.PMT and PERMITS.TXT for each ECDIS). Refer to your ECDIS User Guide. Ensure correct permits are loaded for multiple ECDIS systems. Permit sets are labelled MASTER, BACKUP, RESERVE 1, 2, 3, etc.
2. Load ENCs from exchange sets (download or physical media). Note that some producers provide worldwide data, so folders may not correspond to geographical areas. Load only exchange sets with licensed ENCs as listed in the permit file. The ECDIS manages ENC cell loading based on installed permits.
3. Load the ADMIRALTY Information Overlay for passage planning. It contains Temporary & Preliminary Notices to Mariners (T&P NMs) for paper charts and ENC Preliminary Notices to Mariners (EP NMs) highlighting differences between ENCs and ADMIRALTY paper charts. A permit for AIO is free with AVCS; contact your Distributor if it doesn't display.

Exchange Set

ENC data, catalogues, and metadata files are organised in an internationally recognised standard format, known as an 'exchange set' (e.g., "V01X01"). AVCS DVDs use a different format (DVD1: "M01X02", DVD2: "M02X02").

Readme File

AVCS exchange sets include a 'README.TXT' file with important safety information, which should be read and checked regularly. The latest README.TXT can be viewed on the Support page at admiralty.co.uk/avcs.

AVCS Permits

Each permit is unique and grants access to required ENCs. Permits are supplied in a zipped file. The contents depend on the bridge configuration, as each AVCS license allows use on multiple ECDIS. Extracted permit files (PERMIT.TXT, ENC.PMT) are copied into folders like MASTER, BACKUP, RESERVE1, etc. Most ENC Producers allow data display on multiple ECDIS per license. If restricted, permits are included in the appropriate number of files. Priority displays must be correctly identified. Permits can be supplied via physical media, email, download, or back-of-bridge software, and should be extracted to a readable location.

Other Important Information

General cautions for using ENCs in ECDIS are in the document "Important information for AVCS users" on the Support page at admiralty.co.uk/avcs and in the INFO folder on AVCS DVD exchange sets. Updates applied to ECDIS may impact stored routes; check these effects before use.

Continual Delivery of Updates

Most ENC updates are available from UKHO as soon as they are ready, displayed on ECDIS days earlier than the AVCS weekly batch release. Contact your ADMIRALTY Distributor about connecting to this faster service.

Working with AVCS

Maintaining Your Holdings

1. New ENC Permits are supplied by your ADMIRALTY Distributor when ENCs are added or removed from your license. Install these before loading new exchange sets. If provided, your Holdings Report will be updated.
2. Your ADMIRALTY Distributor will supply AVCS update data. Alternatively, use your ECDIS or other software to request and download updates. If using AVCS DVD and AIO CD exchange sets, data is cumulative; load the latest version. You may receive only updated AIO and ENC data.

Downloaded Data

Your ADMIRALTY Distributor may provide ENCs and updates via the internet or email, allowing you to keep ECDIS up-to-date and avoid delays from physical media delivery.

Cancelled ENCs

ENCs are periodically cancelled as part of worldwide coverage maintenance. If possible, they are replaced with alternative or new coverage to maintain ECDIS coverage. It is strongly recommended to delete cancelled ENCs from SENC to prevent ECDIS displaying outdated data.

Withheld ENCs

If an ENC has a serious safety or operational issue, it may be withdrawn from AVCS until fixed. You will be advised by your ADMIRALTY Distributor to remove it immediately. Since the permit remains, take steps to prevent re-loading until the problem is fixed. A list of withdrawn ENCs is available at admiralty.co.uk/avcs.

Adding ENC Coverage

Additional AVCS Units permits can be purchased from your ADMIRALTY Distributor. Approved orders provide new ENC Permits to 'unlock' new data. These permits are cumulative and unlock existing coverage too. Software applications and some ECDIS allow ordering and delivery of new permits and data directly to the vessel.

Holdings Report

Your ADMIRALTY Distributor may supply a 'Holdings Report' from UKHO systems, showing ENC permits on your license and the latest Edition/Update number for each ENC.

ADMIRALTY Information Overlay (AIO)

Overview

AIO is a worldwide digital dataset displayed over ENCs in ECDIS and other chart systems to provide additional passage planning information. It displays ADMIRALTY paper chart Temporary & Preliminary Notices to Mariners (T&P NMs) where temporary information is not encoded in the ENC. AIO also includes ENC Preliminary Notices to Mariners (EP NMs) highlighting significant differences between ENCs and ADMIRALTY paper charts. No other electronic chart service offers this level of reassurance.

Updating AIO

AIO is refreshed weekly as part of the AVCS Weekly Update, available as a cumulative disc, ISO, zip file, or a week-only zip file. Cumulative files contain the base edition and all updates; load the most recent version. Week-only files are smaller, containing only latest changes, but must be applied sequentially to the most recent base edition. A New Edition is issued approximately every two years. Some bridge software allows downloading updates weekly. Week-only zip, Weekly ISO, and Weekly zip files are available from the ADMIRALTY File Share Service (FSS) at https://fss.admiralty.co.uk. Full ISO/zip sets are 20-30MB; update-only sets are under 1MB. The 'Week-only' will be a full New Edition (approx. 20MB) every two years.

Content

AIO covers the world, except for areas with no ADMIRALTY chart at equivalent scale to the ENC (indicated by 'No Overlay' polygons). Temporary information is assessed for inclusion if it affects an ADMIRALTY paper chart and is a T&P NM, but excluded if it only relates to paper charts or if the producer nation includes it in their ENCs. It's included as EPNM if it highlights a navigationally significant difference between ENC and paper chart.

Compatibility

AIO can be displayed on AIO-compatible ECDIS equipment and some software applications. See the AVCS Support page at admiralty.co.uk/AVCS for a list of compatible ECDIS or consult your supplier. The Overlay data is an S-57 exchange set, installed and updated like ENCs. The AIO permit GB800001 is free for AVCS users. Contact your ADMIRALTY Distributor if you wish to use the Overlay or cannot view it.

Managing Temporary Information with AIO

T&P NMs

The UKHO issues Temporary and Preliminary Notices to Mariners (T&P NMs) containing temporary navigational information for ADMIRALTY paper charts. Mariners only need to hold NMs for paper charts on board. Hydrographic Offices worldwide also issue NMs. If a producer nation doesn't include temporary information in ENCs, but UKHO issues it as a T&P NM for an equivalent paper chart, it's added to AIO. This provides extra temporary information not in subscribed ENCs. T&P NMs display as polygons over ENCs, labelled with the ADMIRALTY Notice to Mariners (NM) number. The full text of the NM is available via the ECDIS Pick Report. Associated diagrams can also be viewed. AIO does not contain paper T&P NMs issued by the ENC producer unless re-issued as an ADMIRALTY T&P NM. There may be a delay between national T&P NM publication/cancellation and AIO inclusion. UKHO avoids duplication, but AIO may occasionally contain T&P information similar to ENC. AIO excludes T&P NMs relating only to paper charts. Some ADMIRALTY T&P NMs refer to non-navigational charts (e.g., Thematic, Maritime Security Charts) and are not included in AIO. A list of ENC producers including T&P NM info in ENCs is at admiralty.co.uk/AVCS and in the INFO folder on AVCS DVD/AIO CD exchange sets. Some T&P NMs may display in AIO before the ADMIRALTY Weekly Bulletin. Official ENCs remain the primary source of navigational information.

EP NMs

ENC Preliminary (EP) NMs highlight navigationally significant differences between ENCs and ADMIRALTY paper charts. They display as polygons with hatched fill, indicating the affected area. Each NM has a unique EP NM number, exclusive to AIO. The full text is viewable in the ECDIS Pick Report. Associated picture files may show the ENC superimposed over paper chart info for clarification. The image shows an example of a Preliminary Notice to Mariners with chart details and quality of data information.

'No Overlay' Feature

Where no ADMIRALTY paper chart exists at an equivalent scale to the ENC, UKHO cannot compare coverage. In these areas, AIO shows a grey hatched polygon labelled 'No Overlay'. ADMIRALTY paper T&P NMs may appear within 'No Overlay' polygons if published for smaller scale paper charts and relevant at a larger scale. Additional information, such as local T&P NMs, may be available from other sources (e.g., local websites, Navtex, port notices). Users should consult these sources when navigating in these areas.

Passage Planning

SOLAS Chapter V requires all relevant passage information to be considered during planning, using appropriate scale, accurate, and up-to-date charts, as well as temporary Notices to Mariners.

Policy of ENC Producers

Most producers now include temporary information in ENCs, received as normal updates or new editions. This information appears as standard ENC objects, allowing ECDIS Route Assessment tools to assess it. Passage plans should be compiled using displayed ECDIS information and pick reports. Some producers do not label information as 'temporary' or 'preliminary' in ENCs, issuing updates as required.

ECDIS Symbology

A 'd' symbol on ECDIS indicates features with time-based attributes (start/end dates), used for seasonal buoys, traffic separation schemes, etc. Date-dependent features display according to the ECDIS date setting; plan routes with the ECDIS date set to the intended passage time. The diagram shows an example of periodic and end date features.

Using AIO

Have AIO active on your ECDIS screen during passage planning. Use ENCs and route checking normally, noting temporary features in pick reports. Check your route with the ECDIS date set to the planned passage time. You may see coloured polygons associated with ADMIRALTY paper T&P NMs from UKHO, providing information not in ENCs. Open the notice text via the ECDIS Pick report to assess and include it in your passage plan. You can annotate your ECDIS display with key T&P NM information. If using the mariner's notes function, check notes against each AIO update.

Compliance

ADMIRALTY paper T&P NMs are not ENC corrections. Audit and compliance inspections require demonstration of using the latest ENC updates and having procedures to obtain and assess temporary information. Temporary digital navigation information can be obtained from:

1. Information encoded in the ENC.
2. Extra information in AIO not in ENCs, where ADMIRALTY paper chart coverage exists.
3. Other sources on board (e.g., Navtex).
4. Local authorities (agents, port authorities).

If information is in the ENC, paper chart notices don't need assessment for passage plans, unless navigating with paper charts.

Further Guidance

The ADMIRALTY Guide to the Practical Use of ENCs (NP231) provides guidelines for using AIO and ENCs during passage planning and monitoring, including T&P NMs.

Frequently Asked Questions

Why does AIO not have all T&Ps?

To avoid duplication and reduce screen clutter. Many countries now issue temporary information as ENC updates. Digital navigators don't need to manage it twice.

How do I get T&Ps?

Digital vessels without paper charts receive temporary information via ENC updates and new editions. AIO provides additional info. For all ADMIRALTY T&Ps, use the Weekly Notices to Mariners Bulletin or digital services from your Distributor.

Can I use AIO to receive T&Ps for my paper charts?

AIO is for digital chart users. Paper chart users must use T&P NMs from the weekly bulletin (paper or download versions).

Will I get a deficiency when the inspector checks my T&Ps?

You must show the latest ENC updates and procedures for extracting all relevant information, including temporary data. AIO provides T&P information not in ENCs. You can use Mariner's Notes on ECDIS to highlight temporary information in ENC or AIO. Temporary information has a T&P Notice number only when it applies to an ADMIRALTY paper chart and is in AIO.

Why is the list of ADMIRALTY T&Ps in the Weekly Bulletin different to AIO?

ADMIRALTY T&P NMs are issued for paper charts and may not be added to AIO. Some T&P NMs in the Weekly Bulletin may have been issued in earlier AIO updates.

How do I know which ENCs contain temporary information?

A list of countries publishing temporary information in ENCs is available at admiralty.co.uk/avcs and in the INFO folder of AVCS DVD and AIO CD exchange sets.

Which countries are not covered by AIO?

AIO serves the whole world; temporary information inclusion follows the rules described earlier.

Troubleshooting

IHO S-58 Standard - ENC Validation

IHO Standard S-58 checks are primarily for ENC validation software used by Hydrographic Offices, not intended for ECDIS. However, some manufacturers incorporate these checks. This may lead to misleading messages about ENC data errors. Report errors only if an ENC fails to load (fatal error or ENC failed import). UKHO will resolve these with the ENC producer.

Incorrect Chart Information

According to IHO rules, producers are responsible for ENCs in their waters. UKHO cannot correct user-reported errors except for GB ENCs. User feedback will be passed to the Producer Nation.

Security Scheme Errors (SSE)

As part of the IHO S-63 Data Protection Scheme, ECDIS displays standard error messages called Security Scheme Errors (SSE). The table below lists SSE codes and their meanings:

Codes 03-09 relate to exchange set authenticity checks. Codes 11-13 relate to permits. Codes 14-15 relate to license validity. Codes 10 and 16 relate to ENC data consistency.

Conversion Errors

When ENCs are loaded into ECDIS, they are converted from S-57 format to the system's SENC format. AVCS data is validated to high standards, but ECDIS may report errors during loading:

1. ECDIS unable to load ENC or Update, or loads and reports an error. This is uncommon. Contact your ADMIRALTY Distributor if the problem persists.
2. ECDIS loads ENC or Update and reports a warning, reflecting minor differences in S-57 interpretation. This is not known to affect correct ENC operation.

Technical Support

Address initial queries to the correct organisation for effective support:

• Hardware problems (keyboard, mouse, display, system console, CD/DVD drive): Contact ECDIS Manufacturer.
• Software problems (configuring/using ECDIS, interfacing): Contact ECDIS Manufacturer.
• Chart installation problems (certificates, permits, AVCS ENCs, error codes): Contact ADMIRALTY Distributor.
• Chart content problems (display anomalies, mismatched data): Contact ADMIRALTY Distributor.

When reporting a chart-related problem, provide the following details:

• Licence Number
• Vessel Name
• ECDIS/Software Manufacturer
• Details of error message (including 'SSE' error code)
• Screen shot(s) of error
• Details of DVD used (date, if applicable)
• Details of permits used (date)
• Details of Cell number(s) errors apply to latest update loaded
• Details of User Permit(s)

Emergency Chart Permits

In certain circumstances, a vessel may need access to an ENC at very short notice. Your ADMIRALTY Distributor has access to the UKHO 24-hour online ordering system for quick delivery of new permits via email or internet. Some ECDIS or bridge software also allow self-ordering and download. If these options are unavailable and new permits are needed due to a medical or safety emergency only, individual AVCS ENC Permits can be obtained from UKHO. Quote Vessel Name, ECDIS User Permit Number, required ENC(s), and reason for request. Permits can be transmitted via email or read over the telephone.

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