Boats in the water

Staying connected when out on the water is a priority for many boaters, from checking weather updates to monitoring marine electronics. However, it’s not always smooth sailing (sorry) when it comes to maintaining a reliable and stable connection. In this article, we’ll explore two common network connectivity challenges on a boat and how to overcome them: limited cellular coverage and NMEA network congestion.

Limited Cellular Coverage

Overcoming limited or weak mobile signals can be quite challenging. There are solutions available, but they usually carry a fairly hefty price tag.

The most common method is to use a signal booster for mobile/data connections. These work similarly to Wi-Fi boosters in your home, which are great but do still have limitations including installation location and available connectivity. Boosters are good for amplifying a weaker signal, but if there is no signal at all, then you are boosting nothing.

The level above this is to go into the realm of satellite phones and satellite Wi-Fi hotspots. Sat Phones and hotspots provide a more reliable connection, and greater global coverage, however they come with a steep price. You have to pay for the phone/hotspot, and then the minutes, etc. added on top, which can quickly turn an already fairly expensive investment into an eye-wateringly expensive one.

Realistically, the solution chosen is largely determined by the requirement for internet connectivity and mobile signal. If it is a ‘nice to have’ feature, but not necessary then a signal booster would be the better choice, and you will have to use the internet when it is available. For those vessels where it is a ‘must have’ or mission critical, then a sat phone or hotspot is a better solution, but consider the costs before deciding.

NMEA Network Congestion

NMEA networks are essential for the seamless integration of the marine electronics on your boat. However, both NMEA 0183 and NMEA 2000 can suffer from data overload due to the limited amount of bandwidth available. this is especially common for NMEA 0183 data, as its low baud rate (4800 or 38400 bits per second) does not offer much bandwidth, thus data overloading is easy. NMEA 2000 with its higher 250000 bits per second is naturally better, but can still struggle on very busy networks.

Managing data load can be challenging, especially on more complex systems that have a high device density. The solution here is to filter and control your data effectively, and also monitor your network for devices which may be causing issues. For example, an NMEA 0183 heading instrument may have the option for fast heading, where the output rate changes from the ‘standard’ 1msg/sec, to 10msg/sec. Increasing this output rate x10 will very quickly eat up the available bandwidth. If your device is outputting fast heading, but it isn’t actually required for your system, switch back to your standard, slower heading output to free up some bandwidth.


NMEA 0183 Data can be managed in greater detail using our range of Professional Buffers and Multiplexers. These devices (except the PRO-NBF-1) offer routing and filtering of sentences. This means that you can configure the devices to only output the data on each port that the connected instrument requires.

Fortunately, with NMEA OneNet now available, a lot of the low bandwidth and high traffic issues can be overcome using Ethernet. As a comparison, NMEA 2000 operates at 250kbit, whilst OneNet (Ethernet) can work at speeds up to 40000x faster than this.

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Network connectivity challenges on a boat can be frustrating but, as this article has outlined, there are strategies to help minimise this difficulty. Such strategies, along with the appropriate technology, can enhance your connectivity and ensure a smoother sailing experience.

For more on NMEA 0183 networking, download the free guide here.

For more on building an NMEA 2000 network, download our e-book here.