Onboard Networks
T
he marine industry is going through perhaps the most significant change in thirty
years regarding onboard systems. Boaters are beginning to embrace what has been
commonplace in our working lives for some time now—the networking of electri-
cal and electronic components—with the result that sending data from one part of the boat
to another is becoming mainstream. Many systems or methods, each with their own
strengths and weaknesses, are vying for market share and technical acceptance. Vast changes
will occur in boat wiring in the near future; changes that may, to a large extent, do away
with wiring altogether. Wireless systems are even being installed on a few very high end
boats today, although widespread market penetration is, I believe, still several years away.
How will boatowners and marine electricians deal with all of this? What skills will be
needed to remain effective and relevant in servicing and installing these systems? These are
the questions I’ll address in this chapter. To facilitate our networking discussion, see the
sidebar opposite on networking terminology, which includes the terms introduced in
Chapter 14.Network Types
Networking is not new to boats; the NMEA 0180 network standard—the first communica-
tions standard created for the marine industry—has been around since 1980, and was fol-
lowed shortly by the 0181 standard, and then 0183, which became widely accepted and was
the mainstay for nearly twenty years. NMEA standards are accepted as the common practice
for how to share specific data information between competing entities or companies.
But over the years we’ve become so used to having nearly unlimited amounts of infor-
mation at our fingertips at all times and in all places that advancements in this area were
all but inevitable. Today, networks and proprietary systems are all the buzz. Some use
twisted-pair harnesses to eliminate the effects of EMI; others use shielded wire sets. But
the field problems related to networking go far beyond a difference in cable types. Issues
such as data transfer rates, the types of data, plug connector compatibility, the number of
devices that can be connected to the network, and the compatibility of equipment from
one vendor to another are concerns as well.
Let’s look at several networks to get a feel for what’s available and how they work.Furuno NavNet
Furuno’s NavNet system is an Ethernet-based network, specifically a 10Base-T system.
Ethernet protocol is available in several configurations that allow for varying amounts of
data to be transmitted. 10Base-T is based on an IEEE standard protocol for identifying sys-
tem features. In this case, “10” simply refers to the data transmission speed in megabits (Mb)CHAPTER
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