Electronic Chart System Questions: What Changed and What Stayed the Same

The Coast Guard didn’t create a new electronic chart system (ECS) requirement. In August 2025 it issued Navigation and Vessel Inspection Circular (NVIC) 01-16 Change 3. That’s guidance. It offers alternative ways to meet chart carriage requirements that are already in 33 CFR and 46 CFR.

That difference matters when you specify a bridge. Read the 2025 circular as a new requirement, and you can over-buy hardware built for an electronic chart display and information system (ECDIS). You can retire paper charts in favor of a system that doesn’t conform to the RTCM 10900 series. Or you can specify against a deadline the Coast Guard’s notice doesn’t set.

Did the Coast Guard Create a New Electronic Chart System Requirement?

No. The Coast Guard’s notice in the Federal Register describes Change 3 as “offering alternative compliance options to the current carriage requirements found in existing regulations.” The circular was issued August 18, 2025. It replaces Change 2, signed May 21, 2020. The notice states no compliance date.

Those options are for vessels “electing to comply with one or more equivalencies,” and Change 3 includes procedures for inspecting them. The chart regulations in the CFR are what those options are alternatives to.

The Coast Guard said something similar about the earlier version. In its 2022 advance notice of proposed rulemaking, it wrote that the Change 2 equivalencies “do not change existing CFR requirements.” That statement was about Change 2, not Change 3.

In short, the circular is guidance, and the regulations are the CFR sections for each vessel class. Seatronx’s earlier overview of the Coast Guard’s updated ECS guidance lists the changes and the hardware options.

Which Vessels and Which Regulations Still Bind?

The chart carriage regulations in 33 CFR and 46 CFR still apply, class by class. For self-propelled vessels of 1,600 gross tons or more, the chart regulation is 33 CFR 164.33. It requires “currently corrected” charts of the area to be transited. Other vessel classes have their own sections.

The Coast Guard’s 2022 advance notice gave its own list of chart carriage sections by vessel type.

Under 33 CFR 164.01, Part 164 applies to each self-propelled vessel of 1,600 or more gross tons in the navigable waters of the United States, except the St. Lawrence Seaway. Further exceptions follow, so read the section in full.

Next, the chart. 33 CFR 164.33(a)(1) names marine charts of the area to be transited, published by the National Ocean Service, the U.S. Army Corps of Engineers or a river authority. They must have a large enough scale and enough detail to make safe navigation possible. Paragraph (b) lets a foreign government’s charts stand in under the same conditions.

Paragraph (c) defines “currently corrected.” It means corrected with the changes in the Notices to Mariners that are reasonably available to the vessel and apply to its transit.

Electronic charts already have a place in the towing vessel section. For a towing vessel not subject to 33 CFR 164.72, 46 CFR 140.705 lists “Charts, including electronic charts acceptable to the Coast Guard, of appropriate scale to make safe navigation possible.”

Read the section for your vessel’s own class and route before you specify a display. Where the class isn’t clear, ask the Coast Guard inspector or the marine inspection office.

What Can an ECS Replace Under the Circular?

A vessel that elects an equivalency may use electronic navigational charts (ENCs) shown on an electronic chart system, printed charts made from government hydrographic data and electronic copies of required publications. That’s how the Coast Guard’s notice describes the options. Each one carries conditions, and the circular sets the details.

For ENCs, the notice sets two conditions. They must conform to the International Hydrographic Organization’s ENC standard and be issued or authorized by a government hydrographic office. And they must be displayed on an ECS conforming to the Radio Technical Commission for Maritime Services (RTCM) 10900 series.

The Coast Guard’s Maritime Commons item of August 26, 2025 said the circular “incorporates essential elements from the RTCM Standard for Electronic Chart Systems (ECS), 10900.”

Publications have their own option. The notice says publications required by 33 CFR and 46 CFR can be kept in electronic format when the originating agency provides the information. It points to table 2 of Enclosure 1 of the circular for the list.

The circular itself holds the vessel and hardware tables, plus that publications table. Read all three before you write a specification.

How Is an ECS Different From an ECDIS?

An ECDIS is a navigation information system. The Coast Guard’s ECDIS page says it can, with adequate back-up arrangements, be accepted as meeting the chart carriage requirement in SOLAS regulation V/19. An ECS is another way to show ENC data. The Coast Guard wrote in 2022 that an ECDIS isn’t the only way.

According to the Coast Guard’s 2022 advance notice, RTCM 10900.7, published April 5, 2017, established four classes of ECS. It also supported integration with radar, AIS, heading input and electronic position-fixing systems.

The 2022 notice also pointed to the similarities between a Class A ECS and an ECDIS. Because of them, Change 2 encouraged mariners running a Class A ECS to complete Coast Guard approved ECDIS training.

So “ECS” isn’t one grade of system. Ask which class a product conforms to before you weigh it against an ECDIS.

For a SOLAS-class bridge, Seatronx’s post on what makes a display ECDIS-compliant covers the ECDIS display side.

What Does an Electronic Chart System Need to Be Accepted?

For the charts the circular covers, the notice names two conditions. The ENCs come from a government hydrographic office, and they’re shown on an ECS that conforms to the RTCM 10900 series. Hardware details by vessel sit in the circular’s own tables, so read them before you buy a display or computer.

Put these questions to the maker in writing:

• Which part, edition and class of the RTCM 10900 series the system conforms to, and for which mix of chart software, computer and display.
• Which government ENC source feeds the system, and how updates are applied.
• The certificates or test reports behind each mark a product lists. Seatronx’s display series, for example, lists IEC 60945 4th Edition, DNV-CG-0339 and IACS E10.
• How position, heading, AIS and radar data reach the system. On a panel PC with NMEA 0183 ports, ask which port carries which feed.
• Whether the display has the DAY, DUSK and NIGHT modes the watch needs, and whether ECDIS color calibration is on the order.
• How the unit is powered from the vessel’s supply. Seatronx’s display series accepts a 9 to 36 V DC input.

In general, a conformity claim is only as useful as the document behind it. Keep the maker’s answers with the vessel’s records.

An electronic chart system can be built as an all-in-one panel PC or as a separate computer and display. In general, the bridge layout decides which fits.

Seatronx labels its MPPC marine panel PC series ECS Compliant and lists optional ECDIS color calibration, DAY, DUSK and NIGHT touch keys and optional NMEA 0183 COM ports. For an all-in-one station, look at Seatronx’s MPPC marine panel PC series and ask which configuration that label covers for your vessel. Where the computer sits apart from the screen, Seatronx’s ECDIS and ECS display series is the separate-display route.

Dates That Matter for Chart Carriage and ECDIS

Here’s what happened when, and who it concerns.

The 2022 dates come from the Coast Guard’s 2022 advance notice, the 2024 date from NOAA’s Office of Coast Survey and the 2025 dates from the Coast Guard’s notice, which sets no compliance date.

The 2026 and 2029 dates come from IMO’s January 9, 2026 briefing on shipping rules in force from January 1, 2026. They concern ECDIS installations, not the Coast Guard’s guidance for an ECS.

Are Paper Charts Still Allowed?

Yes. Under the equivalencies in the Coast Guard’s notice, vessels may use printed charts made with data from government hydrographic authorities, such as NOAA, the U.S. Army Corps of Engineers, river authorities or foreign governments. NOAA’s Office of Coast Survey archived its final paper nautical chart on December 5, 2024.

NOAA’s Custom Chart application lets users make their own charts from NOAA ENC data. Whichever form the vessel carries, 33 CFR 164.33 and the class sections ask for charts that are “currently corrected.” In general, the correction routine for the ENCs and any printed charts belongs in the equipment plan from the start.

Frequently Asked Questions

Does NVIC 01-16 Change 3 Have a Compliance Deadline?

No. The Coast Guard’s notice gives an issue date, August 18, 2025, and no compliance date. It describes options for vessels that elect to comply with one or more equivalencies. The IMO dates of January 1, 2026 and January 1, 2029 concern ECDIS installations, not the circular.

Will a Final Rule Replace the Circular?

In its 2022 advance notice, the Coast Guard said it anticipated that any rule resulting from that rulemaking would supersede NVIC 01-16. As of early November 2026, the Federal Register shows only that advance notice under docket USCG-2021-0291, with no proposed or final rule. A buyer can plan around the circular as guidance and watch the docket.

What Does ECS Compliant Mean on a Product Page?

It’s a maker’s label. The Coast Guard’s notice ties the ENC option to an ECS that conforms to the RTCM 10900 series. So ask which part and edition, which class and which mix of software, computer and display the label covers. Seatronx labels its MPPC series ECS Compliant. Ask Seatronx what configuration that covers for your vessel.

Do Ships on International Voyages Follow the Same Path?

The Coast Guard’s notice speaks to the carriage requirements in 33 CFR and 46 CFR and doesn’t mention SOLAS. For SOLAS regulation V/19, the Coast Guard’s ECDIS page says an ECDIS with adequate back-up arrangements can be accepted as meeting the chart carriage requirement. Confirm with the flag state and the class society before you specify an ECS for an international voyage.

Does the 2029 IMO Date Mean an Existing ECDIS Has to Be Replaced?

IMO’s January 9, 2026 briefing speaks of new ECDIS installations from January 1, 2029. It doesn’t describe systems that are already installed. If the vessel has an existing ECDIS, ask the maker and the class society about software and hardware upgrades before you plan a change.

How Will a Vessel That Elects an Equivalency Be Inspected?

The Coast Guard’s notice says Change 3 includes procedures for conducting inspections for vessels electing to comply with one or more equivalencies. Read those procedures in the circular. In general, it helps to keep the maker’s conformity documents with the vessel’s records so they’re on hand at inspection.

Planning an Electronic Chart System for Your Bridge

Before you order hardware for an electronic chart system, run these checks:

• Find the vessel’s class and its chart carriage section in 33 CFR or 46 CFR.
• Decide whether to elect an equivalency under NVIC 01-16 Change 3, and read the circular’s tables if you do.
• Get the RTCM 10900 part, edition and class in writing, with the configuration it covers.
• Name the ENC source and set the update routine before the hardware arrives.
• Match each station’s display and power to the bridge, and confirm how its data inputs connect.

When those answers are in hand, tell Seatronx about the vessel, the station and the chart software.