Advanced Marine Electrics and Electronics Troubleshooting A Manual for Boatowners and Marine Technicians

per second. “Base” describes the transmission

type (in this case, baseband as opposed to

broadband). The “T” describes the wire type

(in this case, unshielded twisted-pair cables).

(In contrast, the protocol also describes a

10Base-F system that utilizes fiber optics as the

transmission medium.)

The NavNet system uses proprietary lan-

guage protocols and is only compatible with

Furuno products, so mixing and matching

among vendors to create an onboard system

will be challenging. Some Furuno products are

also at least partially NMEA 0183 compatible,

which will allow for some interfacing of non-

Furuno products, but this interface capability

is limited. The NavNet system is essentially a

closed, proprietary system.

Xantrex Xanbus

The Xanbus network system, developed by

Xantrex Technology, is a proprietary system. It

is based on CAN bus, and is compatible with

NMEA 2000. It uses standard computer-type

Cat 5 cabling to connect its various compo-

nents and readily available RJ-45 terminal con-

nectors, familiar to anyone who has worked

around computers or office networks. While

this system uses some NMEA 2000 language

for data communications, it does not use

NMEA 2000 proprietary cabling to connect its

various components. So again, we see that

nothing in this system is really standardized to

allow simple integration of components from

different vendors.

Mercury SmartCraft

SmartCraft is based on CAN technology to

integrate its electronically controlled engine

products with other onboard systems such as

engine monitoring instruments, generator

remote-start panels, and the like. Since CAN

has been used in automotive applications since

the late 1980s, this was a logical move for

Mercury because its applications are centered

on automotive-based engines that have been

marinized, and the automotive market is cer-

tainly much larger than the marine market,

with lots of experience in the utilization of

CAN in car and truck applications. So in this

case, the logic was to go with a proven technol-

ogy. Again, mixing and matching SmartCraft

equipment with other networking protocols is

not easily accomplished.

Raymarine SeaTalk

Raymarine uses its own proprietary SeaTalk

network system, which can transfer data at

100 Mb per second. There have been many

iterations of the system over the years as

equipment needs have increased. Raymarine

also embraced NMEA protocols, produc-

ing both NMEA 0183- and NMEA 2000-

compatible equipment. In the past, though,

integration with other NMEA equipment

from other vendors has required the use of

black boxes to translate and distribute infor-

mation from Raymarine’s protocol to the

open architecture of the various NMEA

standards.

NMEA 2000

In an effort to establish a universal approach

to networking, the NMEA developed NMEA

2000 so that a true “plug and play” protocol

could be established. The NMEA 2000 stan-

dard is designed to allow equipment from dif-

ferent manufacturers to interface with each

other—as long as they are compliant with

NMEA 2000.

The problem is that in spite of this noble

effort, NMEA 2000 is still flawed. There are sev-

eral reasons for this. One is that the NMEA

included a requirement that equipment be

NMEA 2000 certified—at a hefty fee,especially

for equipment vendors who have already

192 marine electronics installation and troubleshooting