around” low-slung islands and
making this technology ideally
suited to areas rich with geo-
graphical features.
While mariners commonly
use AIS for collision avoid-
ance, the Coast Guard also
employs the technology to
mark navigational hazards by
broadcasting synthetic Aids
to Navigation (AtoNs), which
are transmitted by an NAIS
station to augment an existing
charted buoy or other naviga-
tional aid, and virtual AtoNs,
which are AIS signals only,
used in areas that are dii cult
to mark with physical buoys or
other devices.
The buoys marking
Michigan’s Straits of Mackinac
are a prime example of syn-
thetic AtoNs, while the
approach to San Francisco Bay
is marked by virtual AtoNs.
The Coast Guard is also
looking at other ways of
leveraging AIS, as this tech-
nology has the unique ability
to deliver updatable mes-
sages to a recreational vessel’s
MFD or a commercial ship’s
Electronic Chart Display &Information System, if the
vessels are so equipped.
This vision includes syn-
thetic and virtual AtoNs as
well as Application Specifi c
Messages, which can be
broadcast over AIS to cordon
of specifi c zones, such as
whale-exclusion areas, or to
protect maritime trai c from
recently sunk vessels. It could
also be used to shift ship-
ping channels or augment
the “Broadcast Notice to
Mariners.” Moving forward,
the Coast Guard and NOAA
plan to use AIS to share real-
time weather observations and
geospatial data with mariners.
“AIS is currently the only
tool to transfer digital data
onto your electronic nauti-
cal chart,” says Jorge Arroyo,
a Coast Guard program ana-
lyst who has been instrumental
in writing AIS regulations and
standards. He describes an
Application Specifi c Message
as the envelope. “Within the
envelope, [the Coast Guard]
is free to transmit all the other
navigation-specifi c informa-
tion that we wish. It’s our wayof providing digital navigational
data directly to the vessel.”
Things are developing in
the commercial sector as
well. Vesper Marine, a New
Zealand-based manufac-
turer of Wi-Fi-enabled Class
B transponders, recently
announced its WatchMate
Asset Protection service,
which allows companies such
as those in the oil or gas indus-
tries to add virtual AIS beacons
to installations like oil rigs
or underwater power lines.
WatchMate Asset Protection
also provides 24/7 asset mon-
itoring and threat detection,
and can automatically send AIS
text messages to warn of navi-
gational hazards.
Given the amount of naviga-
tional information that an AIS
unit can provide, adopting
this technology is a no-brainer
for cruisers, especially as
more manufacturers enter the
market and prices drop. While
it’s tempting to reach for an
inexpensive Class B receive-
only unit, some cruising
rallies and of shore races now
require that entrants carryAIS transponders. In any case,
the added protection that an
AIS transponder of ers is well
worth the additional cost.
While the “Big Four”
electronic manufacturers
(B&G, Furuno, Garmin and
Raymarine) have of ered
Class A and Class B AIS units
for years, other players in
this market include Vesper
Marine, which makes a vari-
ety of AIS -related products,
and Standard Horizon, which
embeds AIS technology into
its fi xed-mount VHF radios.
(B&G, Garmin, Icom and
Raymarine also build AIS -
enabled VHFs.) More recently,
ACR Electronics, McMurdo
and NKE have entered the AIS
market with a range of innova-
tive products that even include
man-overboard protection.
As the technology continues
to evolve, sailors will certainly
fi nd that AIS can do a whole
lot more than just shine a light
on things that could go bump
in the night.David Schmidt is CW’s
electronics editor.COURTESY OF THE MANUFACTURERSAIS is designed to operate
autonomously and continu-
ously, and thus it’s imperative
that it be properly set up.
Users should install the
equipment near the helm sta-
tion and where radios and
other electrical equipmentwon’t interfere with it.
Each AIS transmitter must
properly identify itself with
an offi cial MMSI number,
issued by the FCC or one of
its agents.
Users must maintain their
AIS equipment in “effectiveoperating condition” and
know how to re-initialize it.
Those carrying an AIS
transponder must turn on
their units 15 minutes
before getting underway and
keep it turned on even at
anchor.Class A users, predomi-
nantly commercial vessels,
should maintain all AIS
voyage- related data fi elds,
such as navigation status,
static draft and destination,
and always use English for
AIS text messaging.Rules of the AIS RoadBOATS & GEARof a Standard Horizon VHF radio (right) both display target information. AIS details such as heading, speed, closest point of
approach, and time to closest point of approach are displayed as text on a Furuno dedicated screen (center).may 2016cruisingworld.com70