Our own experience with AIS in DISTRESS!

April 4, 2026

Our own experience with AIS in an EMERGENCY!

Recently we were sailing on the Westerschelde with a 2-3 knot current. Suddenly the engine failed and the anchor wouldn't hold due to the current.

We quickly called the Rescue Brigade and they were with us within 5 minutes thanks to our AIS!!!

We quickly discovered a rope in the propeller and were able to remove it. Still, it was a very secure feeling that both the traffic control and the rescue brigade could find our position so quickly. All we had to do was give them the name of our boat, and they immediately had us in their sights ;-).

For many boat owners, the first question is: is AIS actually mandatory? In the Netherlands, AIS is mandatory on almost all Dutch waters for commercial shipping and for recreational vessels longer than 20 meters. For most pleasure craft under 20 meters, AIS is therefore not mandatory, but it is considered a valuable addition to navigation, especially on the North Sea, the IJsselmeer, and waterways with a lot of commercial shipping, as is the case for us on the Westerschelde.

What is AIS?

AIS stands for Automatic Identification System. The system automatically transmits and receives data such as ship name, position, course, and speed, giving you a better overview of the traffic around you. You can read this information on a chartplotter, radar screen, laptop, or tablet, depending on your onboard installation.

What is a transponder?

An AIS transponder goes a step further. It makes you visible to other ships and shore stations, which can be a great advantage, especially on busy routes and in limited visibility. For many recreational boaters, an ONWA Class B transponder is therefore the most logical choice, as it is more affordable than the Professional Class A and is well-suited for normal recreational use.

Is AIS a replacement for radar?

No, AIS is not a replacement for radar. AIS is navigation-supportive and should be seen as a supplement to other navigation tools. Radar remains the primary or mandatory system in situations with poor visibility on certain waterways, while AIS provides additional information about ships that transmit their data.

AIS does have clear advantages. It consumes less power than radar, does not require a rotating antenna, and, according to nautical explanations, can "see around corners" in some situations, for example, where radar might be hindered by objects or obstructions.

What do you need to use AIS?

If you want to use an AIS transponder, you need at least the Basic VHF Certificate. In addition, you must register the transponder with the Netherlands Radiocommunications Agency (RDI), after which you will receive an MMSI number that will be programmed into the equipment, along with the vessel's name and callsign.

Who is AIS recommended for?

AIS is especially for:

Sailors and motorboaters who sail on large waters, such as the North Sea, Westerschelde, or IJsselmeer.

Boat owners who regularly navigate among commercial vessels, for example, on large rivers and busy inland waterways.

Water sports enthusiasts who want to expand their navigation setup with extra safety and traffic information.

For a sloop on quiet local waters, AIS is less immediately necessary. For a cabin cruiser, sailing yacht, or fast motorboat making longer trips, it becomes much more interesting.

What to look for when buying?

When choosing an AIS solution, pay attention to:

Do you already have a VHF radio and do you want to work with an antenna splitter or a separate antenna?

Do you want to connect to a chartplotter or NMEA 2000 network? ONWA AIS supports the NMEA 2000 network.

If you set up your installation smartly, you can beautifully combine AIS with a chartplotter, VHF radio, and possibly radar for a much more complete picture on board.