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
SBN-2 Self-contained boat network NMEA 2000
Quick Network Block
If the device number or future expansion is a concern, then I would suggest using the 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.
