Connecting multiple NMEA 2000 devices with limited space onboard

Network installation tutorials and examples are often seen on yachts or large fishing vessels, where installation space is not an issue. However, there are situations where space is limited, such as on smaller vessels. Since installation location is a critical part of the network design, even more so for smaller spaces, it is important to carefully consider your options when building your network. No need to stress, this article will help you to make the most out of the space you’ve got.

Self-Contained Boat Network

For an ‘out-of-the-box’ solution, the Self-Contained Boat Network (SBN) is the easiest solution we can offer. Two variants are available, with the SBN-1 supporting up to 4 devices, and the SBN-2 up to 8. For installations where the number of devices is known, and the power source is close to the device install point, the SBN is perfect.

A2K SBN 1 Self-contained Boat Network
SBN-1 Self-contained Boat Network

The product has a full network within, including a cable for power connection, 4 or 8 drop points and 2 terminators. Essentially the product is a network created with 4 or 8 t-pieces, two terminators and a power tap tee, all condensed down into a product smaller than a smartphone. On a RIB or similar, where real estate can be a challenge, the SBN solves a number of headaches.

One thing that needs to be highlighted is the limitations of the SBN-1/2. These networks CANNOT be expanded. If you have an SBN-1 and need to connect a 5th device, then the SBN-1 cannot be used. Connecting a 4-way drop or 4-way tee off of a drop on the SBN will result in incorrect topology and network design which can cause a number of issues. The same applies to the SBN-2 if you need to add a 9th device.

Actisense SBN-2 Self-contained boat network NMEA 2000
SBN-2 Self-contained boat network

Quick Network Block

If device number or future expansion is a concern, then I would suggest using the Actisense QNB-1. With the ability to power a network and have both left and right sides fused independently, the QNB-1 is a great solution to high-density installations whilst keeping costs down. Sporting 6 drop cable connection points for devices and supporting the backbone connections enables the expansion of the system if required.

The QNB-1 also provides valuable information whilst operating thanks to the LEDs located on the PCB. There are LEDs to indicate fuse operation, power, polarity and data, making fault finding simpler. The QNB-1 offers an extra level of flexibility which cannot be achieved using the SBN by allowing the network to be extended further than the QNB-1 itself.

QNB 1 NEW image1 750x750 1
QNB-1 Quick Network Block

There is a PMW variant which has M12 connectors pre-wired into the device to allow for ‘plug and play’ connectivity or a normal variant which has glands to enable custom lengths of wires to be cut and spliced in. The normal variant also allows for ‘hybrid’ cable networks where STNG and DeviceNet cables can be connected on the same network.

So, if you’ve got limited space to work with, there are still options for your network, depending on your requirements.

For more on building and testing an NMEA 2000 network, read our article here.

For NMEA 2000 network fundamentals, read our article here.