||Please send any comments to me.
This page updated: January 2012
Paper Charts section
Celestial (Sextant) section
Software and Electronics section
"Navigation is what tells you where you are,
even when you aren't."
SailNet - Sue and Larry's "Setting Up Your Nav Station"
SailNet - Denis Glennon's "Cruising Helmsman" (Easynav product)
From Stan Gardner on The Live-Aboard List:
> OK, so who remembers the formula to calculate
> distance from dock to Corona beer locker?
Enter coordinates of both into GPS and check distance. Mine are already
entered (for navigating in a fog) and from the wheel to the fridge is 3.3
ft, but there's also an altitude change of -6.4 ft which can be very
tricky if this route has been run numerous times in the same day. Really
should only be done at the dock.
Sources of full-color paper charts:
Any of the big marine stores: West Marine, Boater's World, Sailnet, etc
From Steve Strand on the
WorldCruising mailing list
On our last cruise we carried photocopied charts for parts of the South
Pacific. For the most part they were useless. They were b & w and we were told
that the quality of the reproduction was excellent. The quality was OK, but
too much detail was lost. Ask for a sample and be very critical. We have several
hundred dollars worth of wrapping paper from our encounter with photocopied charts.
From Dave Black on the
WorldCruising mailing list
We too used photocopies in addition to originals on our
last trip. We found that on those dark and stormy nights, when you go below
in your foulies to plot your position and drip on your chart, copies have a
tendency to turn to mush, ink smears, and life gets more difficult.
Bellingham Chart Printers
BoatU.S. (800-937-2628; full-size copies of NIMA and NOAA charts)
About photocopied charts from Bellingham Chart Printers
from Donald Logan on Cruising World
Ours get pretty wet sometimes and don't smear or get mushy.
You don't lose any detail to the copy process in my experience,
and we've used lots of these. The lack of color is no problem at
all for someone experienced at using charts. If you really want
to highlight the shoal areas or a danger you could just use a highlighter.
You should be looking for them anyway. We don't bother.
There is a difference between "photocopied" charts and
charts made with a photocopy process by a professional company like BCP.
I've made my own copies and they do have the problems you
mention [detail was lost, turn to mush, ink smears].
We also like the downsized version of the charts since Scotty Ann
is small and has no dedicated chart table.
From Brian Woloshin on Cruising World
I have used Bellingham photocopies with no problems.
Yes, you do lose something without the color but it
usually does not matter, just be more careful. There
are a few places in the world where I would recommend
current, full-color government charts, for example:
Torres Straits entering Australia.
The cost savings are enormous. Bluewater also does photocopies,
on slightly better paper than Bellingham.
I have not had any charts turn to mush or have ink smear
but they do need to be kept dry.
From Justin/PYI on Cruising World
Armchair Sailor in Seattle does copies as well.
Most of our charts between Seattle and San Diego are copies from them.
Only our Eastern Pacific chart which we expect to use and
use and use is the real thing. So far (after 3 years) ours
are holding up fine and are perfectly clear. So far we haven't
gotten ours wet yet though. Guess we've been lucky.
From Dan on Cruising World
We have a large set of Bellingham charts, 75% are 2/3 size and the rest are full size.
As far as copies go they are as good as any I have found. The real issues is, do
copies work as well as the real thing. The answer in my mind is a strong NO!
For general ocean passages copies are ok but for island groups they do not provide
the detail I want in a chart. In Fiji copies would be a mistake: too many reefs and
details that are hard to read on a dark night. If money prevents you from getting the
real thing I suggest you carefully mark the chart in color prior to sailing in the area.
This way you can identify hazards in advance and make sure they can be easily seen.
If you have the dollars, don't compromise.
From Paul on Cruising World
I used 'em [Bellingham charts] but spent some winter(?) evenings with a hi-lighter
pen to outline the land edges. Otherwise they're fine.
Colored charts are easier on the eye to quickly find features.
Generally I commit a specific chart area to memory before arrival
so quick reference orientation is easier.
From Don Boyd on Cruising World
I used them (for some areas). Biggest problem is their life expectancy.
Get em wet and they're toast. Highlighters run 3 times as bad as the photocopy
which also smudges. Folds tear very quickly. If you plan to use them again
and again better make a backup because they don't last unless you never take em to the cockpit.
From Dan on Cruising World
Ink highlighters can be a problem on copies or real charts. We have a good selection
of colored pencils that do the job very well. In prep for going into a new area I will
spend a day on the charts and fill in areas of concern with the colored pencil; it not
only leaves me more assured of our safety but also helps me to find areas that may not
be shown in the cruising guides.
Article in Practical Sailor
's 9/2000 issue.
Cut-price charts: Marine Chart Services
Ken Olum's "Chart corrections by chart number"
free Coast Pilot downloads (huge PDF files)
Bowditch's "The American Practical Navigator"
SailNet - Tom Wood's "Reflections on Cruising Instruments"
Cockpit electronics article (instrument placement, magnetic fields, LCD brightness) by Chuck Husick in Nov/Dec 2000 issue of Ocean Navigator magazine
Integrated instruments article by Quentin Warren in Jan 2002 issue of Blue Water Sailing magazine
From Ted and Ann Gordon in "Gently With The Tides" edited by Michael Frankel 
- Integrated instrument system versus standalone instruments:
Integrated system gives more functionality, but is a single point
of failure and is far harder to debug and service.
- Best masthead wind indicators:
- Water-temperature gauge so you can follow warm
currents (Gulf Stream, etc). Not necessary ?
- Want compass in cabin (near berth) so you can easily see
if you're still on course (underway) or if wind/current
has shifted (at anchor).
We bought and installed an integrated set of instruments: knotmeter, depthmeter,
and wind speed and direction indicator. ... The setup is ideal except for
one fault. When one instrument goes out, they can all go out. Sending the
main unit back to the factory (twice) blinded us completely.
My reply to someone who asked what "family" of instruments to buy:
I don't know much about various instrument products.
But I can offer a few general observations from my experience:
I have a RADAR and almost never use it. If I sailed in
foggy places, that would change. It is useful at night
when crossing busy shipping channels or cruise-ship
areas [but AIS would be better]. My particular installation is less useful because it's
down below and I singlehand, the screen faces sideways instead
of forward so it requires a little mental transformation,
and I've never learned how to use the "guard alarm".
Fixing stuff at the top of the mast is a royal pain.
Mount everything (including wind-sensor and anchor light)
on the cabintop or somewhere similar, even at the cost
of reduced performance.
Many cruising sailboats, including mine, have non-working wind-sensors
that the owners have not bothered to replace. That should
tell you something.
My bias is toward simplicity. I wouldn't sail without
GPS and depth sounder and VHF radio. Everything else is optional.
An auto-pilot is pretty darn handy; not quite mandatory.
And although I'm a former computer programmer, I see no
need at all for a fancy electronic navigation system;
I use paper (usually a chart and a guidebook for each area,
and I have both open as I'm travelling). And I don't program
waypoints into my GPS; it's safer to have to be rechecking things
as you go along, keeping you more alert.
My bow navigation lights are mounted on the sides of the toerails,
and constantly fail because of water intrusion, and can be damaged if
the anchor chain comes off the bow roller and slides far back (unlikely). I'm about to mount
them on the bow pulpit, and make them removable so they're only in
place when I'm actually doing a night passage (I think that's legal).
And the original lights are no longer legal for this size boat; I'm
changing to legally-sized LED lights.
Automatic Identification System (AIS):
- Class A transponder: Mandated for big commercial vessels. Uses full-power digital VHF,
so range is 20+ miles (depending on antenna).
- Class B transponder: Lower-power, lower-cost version for recreational vessels.
Transmission power is restricted to 2W, giving a range of about 5 – 10 miles.
- Receiver: receive-only.
Information transmitted: position, speed, navigation status, vessel type, vessel name, and more.
Displaying the information generally uses a graphical display (plotter or computer),
but a text-only display is possible.
Receiver could use splitter to share antenna with VHF radio.
From USCG's "Automatic Identification System Overview"
The AIS is a shipboard broadcast system that acts like
a transponder, operating in the VHF maritime band.
Each AIS system consists of one VHF transmitter,
two VHF TDMA receivers, one VHF DSC receiver,
and standard marine electronic communications
links (IEC 61162 / NMEA 0183) to shipboard display and sensor systems.
The system coverage range is similar to other VHF applications,
essentially depending on the height of the antenna.
The system is backwards compatible with digital selective
calling systems, allowing shore-based GMDSS systems
to inexpensively establish AIS operating channels and
identify and track AIS-equipped vessels, and is intended
to fully replace existing DSC-based transponder systems.
A Class A AIS unit broadcasts the following information every 2 to 10 seconds
while underway, and every 3 minutes while at anchor at a power level of 12.5 watts.
The information broadcast includes: MMSI number,
navigation status, rate of turn, speed over ground, lat/long, course over ground, heading.
In addition, the Class A AIS unit broadcasts the following information every 6 minutes:
radio call sign, name of ship, type of ship/cargo, dimensions of ship, draught of ship, destination.
From William Sellar on World-Cruising mailing list
... Not all commercial vessels are required to use AIS and there are tugs and barges out there with no signal.
Overview article in 9/2005 issue of Sail magazine
Wikipedia's "Automatic Identification System"
A very basic receiver that connects to a PC is around $250 in 4/2010.
There are cheaper hacks, involving modifying a VHF radio and connecting to PC audio input or some such thing.
VHF Radio with integrated AIS Receiver
Info as of 9/2011:
- Standard Horizon Matrix AIS GX2100: about $285; recommended by many cruisers.
- Standard Horizon Matrix AIS GX2150: about $360; slight upgrade from GX2100, mainly in chartplotter integration area ?
- Navicom RT-650 MOB: about $325, but mainly sold in EU, and some bugs reported by users. Unclear to me if it displays CPA,
or you need to connect to chartplotter to see CPA.
Apparently, the Nasa AIS receiver outputs 0 / 5 volts rather than +/- 12 volts,
which makes it hard to connect to other devices ?
Cheapest class B transponders I could find 4/2010:
- ACR 2680 Nauticast-B,
$700 at milltechmarine.
Includes VHF antenna and GPS antenna.
Can run without a PC connected, effectively sending only.
Outputs RS232 (so need RS232-to-USB adapter to connect to PC), to display received info.
Comar CSB 200 Class B AIS Transponder,
$600 at milltechmarine.
Antennae not included.
West Marine AIS-1000 Class B “Send and Receive” AIS Transponder.
$500, GPS antenna included, VHF antenna not.
Class A transponder 4/2010:
ACR Nauticast2 Class A AIS Transponder,
$3000 at milltechmarine
There have been a few articles cautioning that big ships don't always have their AIS
set up properly to see small boats, or at least to display names
of small boats.
So if you call them on the VHF and ask if they "see" you, they may say no because their
AIS is displaying only MMSI numbers, not names. Or something more dangerous may be wrong.
A big-sailboat crewman told me 4/2010 that they've seen ships where the AIS information
was programmed wrong, even with the heading wrong (not sure how you can program that wrongly).
AIS web-sites and mobile device (iPhone, etc) applications
often show information that is up to an hour old, and their antenna is somewhere ashore, so don't expect it
to match the real-time data you see on your boat's equipment.
From Mike on BoaterEd
In an AIS message the distinction between moored and underway is purely an operator input,
which means it can be incorrect.
You can trust only the automatic portions of the AIS messages (speed, heading, position
and MMSI number). You should not blindly trust the operator input data (navigation status,
IMO number, ship name). I once detected a 800 foot long ship claiming to be "Underway-Sail"
and often see ships claiming to be moored which are moving at 12 knots.
The AIS information associated with a target, as your equipment
displays it, can change over time, because some info is sent
every 10 seconds or so while underway or every 3 minutes at anchor,
and less critical info is sent every 6 minutes. So a target might show up first with
only an MMSI number shown, and later have the ship name appear.
Military ships will not show up on AIS.
From Great Loop discussion list via BoaterEd
There is a similar discussion going on about this on the Great Loop discussion list,
and a well-seasoned cruiser I know posted this summary which I picked up from the digest this morning
(owns a Monk 36, by the way): Obviously one reason I post this is because he largely echoes my
comments so far on this thread. And to a large degree those of others who cruise their boats long distances:
Perhaps this might help some folks put into context what AIS can and cannot
do. It's not my intent to beat a dead horse. These were some thoughts that
came up in an off-list exchange that I thought might add more light than heat
to this discussion. Item 1 is history, 2-12 are as I have personally observed
them over the last 6 years and 30K miles of cruising (several trips up the
Hudson to the Thousand Islands, the Great Loop, the A-ICW 9 times, the NJ ICW
from Cape May to Manasquan twice, the Abacos and the St. Lawrence Seaway):
1. AIS was developed under SOLAS for COMMERCIAL SHIPPING, *not* pleasure
craft. It is an international (SOLAS) safety standard. In the US, the FCC
did not type approve Class-B (pleasure boat scale systems) AIS units until
long after they were available from manufacturers; they came within
nano-meters of not type approving Class-B in the US at all (for what I now
realize were pretty good reasons!). They were "encouraged" to approve by
Homeland Security, who thinks they can keep track of *all* boats with motors
using AIS; just try to imagine that chaos!!!
2. Not all commercial vessels are required (by coast guard regulation) to
3. Only a small percentage - the largest gross tonnage - commercial vessels
actually carry AIS.
4. Small harbor tugs and work barges *do not* carry AIS.
5. Most Moran and McAllister ocean-going tugs do carry AIS; they do not -
will not - respond to Class-B callers !
6. The Navy and the Coast Guard carry, but usually do not use, AIS (run in
"quiet" mode); the bad guys might see them coming, dontcha know ...
7. On the Inland Rivers, only large towboats that operate in the controlled
ports of New Orleans and Mobile carry AIS; that accounts for 75% - 80% of
large river tows; Casino boats do not generally carry AIS.
8. On the East Coast A-ICW, only a very small percentage of commercial
traffic carries AIS; only a slightly higher percentage on the gulf coast ICW,
and the bulk of that in the area of New Orleans and Mobile.
9. In NY Harbor, only a small percentage of commercial traffic carries AIS.
10. Some of the Staten Island Ferries carry; some do not. All ferries or
cruise boats carrying 150 passengers or more have a security zone associated
with them, so if you're near one, AIS or not, you're already in trouble.
11. Water taxis and fast ferries from Atlantic Highlands and Weehawken *do
not* carry AIS.
12. Most large ships do filter AIS in harbor areas, and on the Chesapeake and
By far, the area where having an AIS receiver was of the greatest value to
Sanctuary was on the Tennessee River and the Tenn-Tom Waterway, where we could
call tows by name; it was also of moderate value in the Tennessee River Lake
country. It was useless in Mobile Harbor because of the number of hits,
mostly from moored ships. This is typical of all large harbors, including NY,
Elizabeth, Baltimore, Norfolk/Portsmouth, Morehead City, Charleston and
Savannah. It has never been of any value on the Neuse River, Pamlico or
Albemarle Sounds, Cape Fear or Beaufort River, or Port Royal Sound. It is of
little value on the Chesapeake and Delaware Bays, and Tampa Bay, where the big
fellows all run in well-documented channels. It is of no value on the
Chesapeake Bay Rivers (James, York, Rappahannock, Potomac), the Gulf-ICW or in
South Florida generally. It was of little value on the Great Lakes, except
possibly for night crossings, I guess.
That leaves the remaining issue of clutter. That's obviously up to each
captain, but my advocacy remains with a dual-channel receiver, not a
transponder. Just keep a good helm watch. At trawler speeds, that's plenty
of safety margin!
From AIS article by Rebecca Childress
in 10/2010 issue of Blue Water Sailing magazine
- AIS sends info on two VHF channels. An old single-channel receiver that
flips back and forth between the two channels often will miss information broadcasts,
perhaps for hours. Upgrade to a dual-channel receiver.
- A standalone AIS unit is preferable to a system using a chartplotter or laptop computer and external GPS.
It will use much less power, so you're more likely to use it 24/7, as you should.
It may allow adding a louder external alarm. The controls will be simpler.
Reliability will be higher. You can add connections to chartplotter or laptop computer
as a backup in case the AIS display or buttons fail. Author's experience has been that dedicated unit
displays info minutes sooner than chartplotter or laptop, and chartplotter sometimes displays incorrect details.
- Your info (including MMSI number) has to be programmed into the AIS transponder by the
vendor before it is shipped to you (legal requirement).
- Connection to a laptop computer may be required to finish installing the AIS unit and verifying that it works,
even if the laptop is not required for routine operations.
- Some transponder units include VHF switching so your VHF radio and AIS transponder can share the same VHF antenna.
- Author installed and likes the Vesper Marine AIS WatchMate 650 display
and Digital Yacht SPL250 transponder-and-antenna-splitter.
There is a new unit, Vesper Marine AIS WatchMate 850 ($1100),
which integrates everything into one box.
10/2013: it has been demonstrated that a hacker can "spoof" AIS pretty easily,
changing ship positions, shutting off transmitter, etc. But AIS still is worth using.
Summarized from letter in Jul/Aug 2001 issue of Latitudes and Attitudes magazine:
For a lead-line, use a fishing pole with a 3 oz weight tied to the end of the line.
Tie a bright float to the line at distance (draft + 1 foot) from the weight.
The weight must be heavy enough to sink the float.
Cast the line.
If the float is visible, the water is too shallow.
GPS section of my Boat Electrical page
RADAR section of my Boat Electrical page
RADAR Detector section of my Boat Electrical page
SONAR section of my Boat Electrical page
Speedtech portable instruments
From Will on IRBS live-aboard mailing list:
Hand held windmeters: There are the 3 cups type (fragile/expensive). There
are the modern tiny turbine type
(expensive and need batteries). There are
doubtless other types. However - the time has come for me to own one for
myself, and the type I am looking for is the
disc-rises-up-inside-a-clear-cylinder kind. And no-one seems to make them anymore. ...
From Gene Gruender on IRBS live-aboard mailing list:
... at the boat's level the wind is always a bit gusty, making
its way around the various parts of the boat. ... If we use
ours it's more for entertainment than real need. ...
From Dennis Biby on IRBS live-aboard mailing list:
The only time I've attempted to use a handheld anemometer was in an Atlantic
crossing. When we were most interested in wind speed, the waves were so
high the deck-level anemometer was pretty useless.
It seems to me that there are only four windspeeds: motoring, full sails,
Handheld anemometers reviewed in 10/15/2000 issue of Practical Sailor
From Wolfgang on Cruising World message board:
A normal barometer is of no use aboard.
If you take this meteorology stuff seriously, then you have to buy a barograph.
Only with an accurate barograph you'll be able to follow the trend of the
atmospheric pressure and just then you might be able to draw the right conclusions.
WeatherMate Recording Barometer ($89)
But this will lead you into a quite different price category.
Furthermore if you take it *completely* seriously, you'll have to
record humidity and air temperature as well.
From Rick Kennerly on
Yacht-L mailing list:
... Within a six to ten hour window, [WeatherMate] is NEVER wrong. It appears that
the software applies all those little rules of thumb about the weather
(pressure, duration, and rate of change, as well as humidity and temp)
to make its predictions. Mostly though, I use it to watch for trends ...
Battery life: Two years and counting, so far.
Binoculars tested in Oct 2000 issue of Cruising World magazine
Buying guide article by Dave Baldwin in 10/2004 issue of Sail magazine
- Power X Diameter
(higher power == see better, but harder to steady;
bigger diameter == gathers more light, but heavier and more expensive).
- Lens material (must be glass).
- Coatings (to avoid light loss from reflection; best is multi-coated on all surfaces [FMC]).
- Optics: roof prism, or porro prism (equally good).
- Waterproof or water-resistant.
- Shock resistant / body coating.
- Center focus or individual focus (center focus is easier to use but harder to waterproof).
- Eyecups (to shade eyes, and adjust to eyeglasses).
- Image stabilization or not.
- Built-in compass (with light) or not.
- Range-finding reticle or not.
Adequate non-marine binocs are available at Walmart for $25.
Don't waste money buying expensive binoculars. Simply stand closer to the object you wish to view.
From Patrick Lynch via Kate Munson on Cruising World message board:
- Bretton plotter is easier to use at sea than parallel rules.
- If knotmeter fails, but sensor wheel spins freely, might be worn axle.
See if wheel wobbles sideways and hits housing.
May have to replace entire sensor.
- Very expensive knotmeter with no moving parts:
You can buy little "post-it" type arrows from an office supply store which will stick
to a Maptech Chartkit page. As we headed down the ICW all we had to was move the arrow
down the page as we took a fix on an aid to navigation. One arrow will last several days
and you get lots in one package for very little money.
From Tony du Bourg in Good Old Boat newsletter:
Some hints for removing a bubble from a Danforth compass.
I used to have one 20 to 30 years ago and finally switched to Ritchie because they were more helpful with parts.
A bubble usually means you need new gaskets. There are two large screws with O-ring seals on the
side that can be removed to replace fluid.
If the bubble is small, here's a cheap trick: remove the compass from the bracket, turn it
on its side so that one of the screws is on top, and remove the screw. Jiggle the compass
until the bubble is in line with the hole. Gently push a small blunt dowel through an appropriate
hole in the bottom of the compass, until you push on the expansion chamber diaphragm,
thus reducing the volume of the compass and expelling the bubble. When the threads of the hole
are awash with fluid, reseal with the screw, seating it fairly tightly.
The proper method: add, or better yet, replace the fluid completely after draining the compass.
Be sure all liquids are compatible (alcohol vs. kerosene). Take a drop of the old and a drop
of the new on a piece of glass and test that they are miscible (will mix and not separate).
From Sabreman in Sailnet forums:
To keep the clear plastic dome on the compass from crazing and clouding,
apply a liberal coating of mineral oil very month or so (whenever it looks dry).
New compasses will stay new nearly forever. Minor crazing on older compasses will disappear.
For winter storage, apply an extra heavy dose and wrap the compass with a plastic bag.
In the spring, the oil will still be there and the compass will look great.
A wind-indicator is a very useful instrument: it always points to where you want to go.
Common navigation mistakes that lead to serious problems, from
Tom Waid's "Yacht Systems" / Navigation:
- Misreading the chart.
- Thinking that you're somewhere that you're not.
- Being too lazy to draw a line on the chart.
From "The Voyager's Handbook" by Beth Leonard
"Almost all of the boats that were lost during the course of our circumnavigation
were lost closing with land at night."
Bill Myers' "Celestial Navigation - What are the Options ?"
Omar F. Reis's "Celestial Navigation Fundamentals"
Good overview of celestial navigation in Reed's Nautical Almanac
eHow to Buy a Sextant
Sextant article in 4/15/2001 issue of Practical Sailor.
"Celestial sights with plastic sextants" article by David Burch in Jan 2002 issue of Blue Water Sailing magazine
Celestial Navigation Net
Home-study: Starpath ($90).
Home-study: International Navigation School ($225).
From Sam Chan on Navigation-l mailing list:
- Starpath says
get traditional half-silvered horizon mirror, not full-view or whole-horizon mirror.
Makes it easier to see dim stars, and see objects against same-colored background.
- Celestaire says
whole-horizon has "very slight reduction in light transmission and
reflection which may affect marginally lighted observations" but it
"greatly simplifies 'bringing down' the celestial body and makes it
easier to hold the body in view" and
"one can more quickly take observations" with whole-horizon.
- Bigger mirrors are better.
- Need artificial horizon attachment if you want to practice in the SF Bay area.
- 6x magnification makes it easier to see with aging eyes,
but 4x makes it easier to keep fix on object when on moving boat.
- Some courses use Pub 229, but ASA test uses Pub 249 ?
- Celestaire says
ASTRA IIIB (Celestaire, about $460)
is best value for metal sextant;
Davis Mark 15 (Celestaire, about $110)
is best value for plastic sextant.
- Barebones student sextant is Davis Mark 3
(Celestaire, about $47).
- From Clare Allcard: To take a star-sight, turn the sextant upside-down.
Find the star, then bring the horizon up to meet it.
When almost correct, lock the sextant arm, flip the sextant over,
and adjust to finish.
- Take star-sights at twilight (dusk) or dawn, so you can see a clear horizon
as well as the stars.
- Plastic sextant: plastic is unstable in warm
climate, and cheap plastic filter could
cause eye damage during sun-sights.
- GPS time readout may not be accurate enough to use for celestial navigation.
Some GPS's may not adjust for the current leap-second count, or
may pick it up after running for 12 minutes or so.
And the screen update rate is a factor; updating the
time display may be lowest priority of the software.
Use accurate timepiece, or radio station WWV ?
- Want digital watch with big digits and back-lighting.
- From Jon Gray: Metal sextant will make the experience
more enjoyable than plastic sextant. Also, most people screw up
the plotting part of the operation rather than the sighting part.
Re: Astra IIIB
The practice bubble horizon is difficult to use. There is no magnification.
The slit aperture makes me see double of the reference line in the sight.
Combine that with trying to hold the sextant steady so the bubble is
centered while adjusting the sight ... it can be frustrating.
Software and Electronics
"You're not lost if you don't care where you are."
Ways of doing electronic charting/routing:
- Software on a PC: $0 to $2000, plus price of PC.
More flexible, easier to integrate with other software/hardware,
easier to upgrade, easier to repair, maybe more features.
- Software on a PDA
- Chartplotter (dedicated hardware): $3000 to $12000.
Won't crash as easily as a PC, better visibility in various light conditions,
more rugged and waterproof.
- Online (when connected to internet).
"Levels" of software functionality
(partly from "Navigation Software" article by Tony Bessinger and Bill Biewanga
in 1/2001 issue of Blue Water Sailing magazine
- Viewer: display chart.
(e.g. Easy-ENC by Caris,
SeeMyDEnc by Sevencs, "dkart look")
- Planner: display chart, plot course,
download waypoints to GPS, print chartlet,
receive actual track points from GPS and plot them.
No real-time connection to GPS.
- Real-time navigation: display chart with
real-time data from GPS and other instruments.
- Fully integrated: all functions, fully integrated with RADAR,
auto-pilot, tide and current info, weather, weatherfax, satellite images,
boat's polar plot, etc.
From Len den Besten on World-Cruising mailing list
What you must realize is that you don't just buy a navigator-program;
at the same time you choose a type, a family of charts.
Amongst others you can choose C-Map, or Maptech or Transas. ...
SailNet - Jim Sexton's "Electronic Charts 101"
SailNet - Jim Sexton's "Developments in Electronic Charting"
SailNet - Jim Sexton's "Terms of Electronic Charting"
SailNet - Jim Sexton's "Updating Electronic Charts"
SailNet - Jim Sexton's "Advanced Electronic Charting"
Bluewater's "Electronic Charting 101"
Bluewater: Rob Handley's "Electronic Charts"
NOAA list of ENC software products
- Boatcruiser from Navsim.
- The Cap'n
($195 for First Mate, $495 for Voyager).
From Mitch on
IRBS live-aboard mailing list:
We used The Cap'n extensively during our cruise. We looked at several
before settling but that was the most robust and stable of the programs we
looked at. There is a bit of a learning/adjustment curve, however. At one
point sailing from the Turks and Caicos to the Exumas it ran continuously for
3+ days without a problem. There are a lot of features that take a bit of
investigation to find but it's worth it. It works with virtually any chart
From Geres on Cruising World message board:
Most people we met did not like The Cap'n - most probably because it does
take a bit to learn. Before you get advice against the program, make sure
it's coming from someone who has actually used it in a real-life situation.
The most commonly used program, I would guess from talking to other cruisers
was Nobeltec Visual.
... I left thinking that electronic charting would be
like a hobby - but we ended up using it a lot - and we loved it!
Oh yeah - the Explorer Charts on the Maptech CD of the Bahamas are
I've been using Cap'n Voyager (upgraded from 4.5) and have
been quite pleased with it. Very intuitive; can use charts
from several sources (not just proprietary); I like its ability
to display in two panes (multiple charts or same chart in two resolutions);
and nice extras such as log, inventory, etc.
Latest versions have a security mechanism that uses your
computer's serial number, but the company will let you
have an unlock code for a backup machine too; you don't
have to pay for two copies.
($279 for Tracker, $470 for Professional).
- Deckman from Sailmath.
- Eldridge TideWare ($79).
Includes vector charts.
- Freeboard (free).
Uses computer (anything that can run a Java GUI application),
Arduino board, and
Raspberry Pi board.
Connects together NMEA-0183 sensors and instruments, provides
chartplotter and auto-pilot functionality.
- Force9 from ATM ($40).
- FUGAWI ($95).
From LB on the
Morgan mailing list:
I have used Fugawi. Sometimes it can be cantankerous to get
set up, but it does work very well after initial setup. The
real advantage of it is the ability to scan in a chart from
any source. In fact a chart drawn on a napkin can be scanned
in and accurized.
I found it easy to scan in and use charts from many sources.
- Maptech Offshore Navigator ($200).
From Tim L. on Cruising World message board, 5/2001:
I use it regularly and I like it.
It works well and is somewhat less expensive than the alternatives.
It does crash sometimes, but less often in the recent releases.
I'd recommend it. They also have a good demo to download.
The chief limitation is that it only supports a short list of GPS units
for upload/download of waypoints but that's true for all of the competitors.
No one seems to support Raytheon or Sitex.
- Jeppesen MarineMap ($379).
No new versions will be produced; acquired by Nobeltec; upgrade to VNS.
($395 for MaxSea Navigator, $595 for MaxSea Yacht).
- Memory-Map ($176).
- NaviCharT (180 Euro plus 165 Euro annual updates).
Includes worldwide charts.
- NavPak and MapSetup
($99 for lite, $180 for pro) from Global Navigation.
Also free download of navigational software that allows
plotting and waypoint/route entry, but no GPS link.
- Odyssey ($149) from Weems & Plath (but really from Nobeltec ?).
- OpenCPN (free).
From David Marchand on
IRBS live-aboard mailing list:
"I use OziExplorer
which I like very well. I have also used The Cap'N and I
prefer Ozi's very clean and intuitive user interface."
- RayTech Navigator ($450).
Formerly "KiwiTech Navigator".
From Jim Stimpson on Great-loop mailing list:
I use Raymarine Raytech Navigator 4.1 software with Maptech Raster charts.
It is a very good program. It
will run Maptech raster charts or C-map NT charts. It will also run photo
overlay charts. It fully integrates with Raymarine Seatalk and will display
any Seatalk data from your network on your laptop screen. If you have
Raymarine high speed bus (HSB-2) it will even overlay your radar image on
your chart. All raster charts are quilted together which lets you zoom from
detail showing your boat in your slip to the entire world. It has the
ability to transfer routes to friends by e-mail. The only problem with the
program is that it takes a very powerful computer to operate properly. The
most important requirement is a "gaming quality" graphics card (NVidia
GeForce 4 with a minimum of 16 MB recommended; I have 64 MB).
- ScanNav ($50)
- SeaClear (freeware)
"Unfortunately no commercial chart formats are currently supported,
as the suppliers of digital charts use proprietary file formats,
require hardware keylocks, require license $$$ for reading the charts,
and in some cases even have the policy their charts may not be used
in free software."
- Tsunamis ($180 for Coastal, $630 for Offshore) from Transas Marine.
From Len den Besten on World-Cruising mailing list:
What you must realize is that you don't just buy a navigator-program;
at the same time you choose a type, a family of charts.
Amongst others you can choose C-Map, or Maptech or Transas. I make
two assumptions here: 1) You do not own a Garmin GPS cause in that
case you should look at Garmin's Bluecharts. 2) You don't want to
scan charts or use jpg- or bmp-files and their likes. You want
vector-charts with layers of information depending on the zoom-level you select.
I stumbled upon Tsunamis because I could buy a copy with the world
chart folio for a bargain.
I don't like the navigator program very much cause it's old-fashioned
and not intuitive. I do like the rugged stability and most
of all the quality of the worldwide Transas charts.
They are not cheap. For example, the coastline from Cherbourg to
Hamburg: Maptech 550 euro, C-Map 550 euro, Transas 847 euro. On the
other hand: updates Maptech 50%, C-Map 50% and Transas 10%, so when
you plan on updating regularly (insurance?) the calculation is simple.
Tsunamis does what you ask of a navigator program, but nothing more.
When you want extra's you should look at MaxSea. It comes with extra
modules (Routing module, Performance module, ARPA/AIS module, GRIB-files)
which are expensive. It works with C-map charts.
I won't go on blabbering about FT Navvision, Maptech Offshore
Navigator, WinGps4, Nobeltec Visual Navigation Suite, Raymarine
Raytech RNS, or SeaPro. IMO, when you just want to navigate,
Tsunamis is good value for money, especially when you plan on
updating regularly. When you want more possibilities, look at MaxSea.
- Visual Navigation Suite 5.0 ($470) from Nobeltec.
From SG on Cruising World message board:
I just upgraded to Nobeltec Suite 5 -- w/ the Passport Chart system.
From Ronald on Cruising World message board:
It's very nice and relatively problem-free. ...
The quality of the Passport charts and their speed is a very nice
improvement -- and they don't take much memory for more information.
It utilizes the open format so that you can use your BSB or Maptech
raster charts and the "pictures" etc. (in most cases).
I've known some people who use the Cap'n and the Maptech programs
and are pleased with them too. I just think that the Nobeltec Suite
with its integrated functions is very nice. The tides and currents
with the ability to visualize were fantastic on our New England cruise.
You could compare the various scenarios on multiple screens (as long
as the Windows '98 didn't crash) and really get a feel for the options and effects.
The only "pain" downside is that you can only install the
program on two machines. If you want to change, you have
to "deinstall" it. I'd like to have the ability to have
it on my office, home, portable, and boat ... but then maybe I
should just be more disciplined ...
Nobeltec 6.0 has arrived. I own version 5.0 and do like the Passport vector charts,
which are a lot more detailed and clearly defined than the raster chart kind.
I was looking forward to V6.0 but, wow, by the time I added-up tonight the
cost of the upgrade $150, to the chart update subscription service $99,
to the cost of adding 3D charts $250 and the weather service subscription
starting at a measly $19.95 a month, I was all of a sudden up to an upgrade
cost of close to $500 after consideration of the upgrade discounts!
I think I will let that upgrade wait for a while.
Well, at least until next May ... Wow ...
From Mary Lindemann: VNS requires a parallel port be present;
won't run on a USB-only computer.
From Ron Radko on Cruising World message board:
... the charts are only about $250 per region for the USA, [but]
the international charts are *way* expensive, and the "regions"
typically are half the regions that you really need.
The Med for example required about $6000 US worth of charts
for the North Shore and Turkey.
Electronic charts article (trends; vector charts) by Ben Ellison in Jan/Feb 2001 issue of Ocean Navigator magazine
"Navigation Software" article by Tony Bessinger and Bill Biewanga
in 1/2001 issue of Blue Water Sailing magazine
Nobeltec and Cap'n reviewed in 6/2000 issue of Practical Sailor
A 4-page review of electronic charting systems is available to
Seven Seas Cruising Association
members from SSCA for <$1.
Useful descriptions of several packages at Navstore.com
Software tested in 2/1/2002 issue of Practical Sailor
Article by Dan Piltch in March 2002 issue of Cruising World magazine
From Jerry K on Cruising World
I also looked into the Nobletec Suite.
We are planning on several years of cruising from the
Mid-Atlantic area down the ICW, through the Bahamas
and then into the Caribbean. After investigating the cost
of the Nobletec charts for all this I was informed that
it would run about $2000. That is just too expensive for me.
I guess a chart program like that would be ok if you were staying in one area.
But the nature of cruising means that we will not be staying in one area
so I guess I will have to settle with paper charts which you would need onboard anyway.
The technology is nice but until the cost becomes reasonable
I will have to continue living in the dark ages.
From MacBF on Cruising World
One thing often overlooked in these software selections
is the cost of the necessary raster source charts.
Jeppesen have their own variety which is about half the
price of the Maptech series. This can add up considerably
if you are looking at going down the East Coast for example.
From Gary Elder:
I don't recommend that anyone substitute using these programs instead of
mastering some basic piloting skills.
We are using Chart View Planner. I think it is wonderful.
Considering that I don't use a computer
on-board, and that I do coastal cruising,
this is perfect for me. I can make routes as quickly as I can click the
mouse, compare parallel routes on screen, print the 'route strip charts'
that I want to keep, and go sailing. The Perfect Quilting feature is really
nice. This lets me move from one chart to another without even a hiccup -
even if the two charts are not the same scale. If two adjoining charts are
different scales, they will be shown as if they are the same scale. Also,
it never runs to the edge of a chart, within my operating area.
Up-load/down-load of waypoint and route information between the computer and GPS
is no problem.
If I were going to use a computer on-board, I would buy the next level up,
that shows position info on-screen in real time.
We use Maptech Reg. 8 Chart CD with the Chart View Planner, and it too is
wonderful. The charts look better than real, and they are just about the
most up to date available.
I also have Maptech's Chart Navigator. Awkward to use, slow, and jerky.
A friend uses The Cap'n and likes it. I have seen it in action, and it
appears awkward to use, jerky, and runs right to the edge of a chart before
it tries to find the adjacent chart. Then there is a delay while the next
chart 'loads'. Perhaps he does not know how to operate it properly.
I don't use the tides and currents on my Chart View Planner. I don't like that
information to appear on my charts. I do use a separate tide program, but on
the other hand, tide tables are free just about anywhere in this country.
... for long distance cruising the cost of charts could put a
serious dent in the kitty. The Maptech CD Chart Kit for the Florida West Coast
and the Keys sells for about $200, while the paper version, which are wonderful
charts, sells for about $115, which is much less than the equivalent NOAA charts.
The same thing applies to GPS chart plotters. For example, currently (Nov
2000) a Garmin G-Chart covering Tampa to Key West sells for about
$300 (similar for the competition). G-Charts for the entire east coast would
cost serious money.
Generally, I subscribe to the KISS philosophy, and even though I love the
hi-tech tools, I won't be buying a chart plotter any time soon. A basic GPS will do
everything necessary, and is so cheap (Garmin 12 is currently $130) that if it
vomits once just throw it away and get out a spare. Besides, we should all be
keeping a current DR anyhow. The Chart View Planner that I use is definitely a
toy, and great fun. However, I don't plan to use it outside my local area.
From Glenn Duncan on Cruising World
I'd say the [Cap'n] program was not set up properly if it was stalling out at the edge of charts.
In Cap'n 4.0 and 4.5, at least, you can tell the software it should switch charts
5 miles (or 3 or 8.7 or whatever) from the edge of the existing chart.
Personally, I find the lack of a quilting feature in The Cap'n annoying,
but I also find Visual Navigation Suite (with quilting) is unstable and drops out too often.
Different strokes for different folks.
From Jim McCorison on The Live-Aboard List
We've settled on Nobletec VNS, but did so in a round-about manner. A friend
sold me his Chartview Pro for diddly-squat in thanks for helping him with
his boat systems. I liked it ok, but was concerned that they had been
bought by Nobletec and that there might not be future support. So we
upgraded to VNS. (Nobletec treats Chartview Pro owners as if they own a
prior version of VNS.) Since we're in the middle of an extensive refit,
I've only had one short cruise with VNS so can't vouch for it either way.
I've been playing with it in the interim to get a feel for it.
I can say that with each successive patch or version upgrade more and more
parts of it are broken. When talking to Nobletec at the boat show I was
told that the patches and upgrades really don't install well and that I
would be better off uninstalling and reinstalling a complete new version
instead of the step-by-step patches. Big hassle, but we'll see if it cures
The other thing I've noticed is that it is a major memory hog. And to make
matters worse, it has memory leaks especially near the outer edges of the
installed charts. I have a 1 ghz machine with 256 megs of memory and VNS
will periodically bring it to it's knees, but so far only when I've been
manually scrolling around large areas of the ocean. (I was playing with
straight routes Vs great circle routes.) Even after closing all the charts
I had open, it wouldn't release all the extra memory it had allocated. I
finally had to just shut it down.
But it is easy to use, and that's a big plus. Time will tell. We may return
using only our backup charts.
From Brian Strong on Great-loop mailing list
After a decade of using Nobeltec and most of the other
echart nav systems, last month I did a side by side of
Nobeltec and Fugawi ENC comparison on a CT - Lake
Champlain and return.
My advice - if you already have a program and know it
well - stick with it. Familiarity may breed contempt
but it is invaluable when you have a problem.
If you are just starting out, Fugawi ENC wins hands
down. It supports raster and ENC [the free charts]
very well, is less expensive, and the support is
excellent. ENC is the future and Fugawi clearly is in
the lead so learning it now will pay dividends.
From David Kramarsky on Great-loop mailing list
We have used several different electronic charting systems, and there are
things you should know about each:
Nobletec is a fabulous system, but the software is about $500 and each
Passport chart region is $250 (US). The Passport charts are vector charts; that is,
they are built up from a database, and thus are always in the same
orientation, and the detail is incredible. However, the Passport charts for Lakes Erie
and Huron are for US waters only; they do not show Canadian detail. The
Nobletec system supports Maptech raster (scanned) charts, and some others, but when
I started using Softchart raster scans, the system was unhappy and gave me
Maptech makes great charts. Each chart disc also comes with photos and a lot
of other detail such as marine facilities. I do not like the system; it is
short on controls and hard to use underway, though that may be a function of
what I'm used to.
The Cap'n seems to be a better system, and supports both Maptech and
Softchart charts flawlessly, and the controls are good. Neither Maptech or the Cap'n
support vector charts.
You might also look at Garmin's Blue Chart package. A single disc covers
everywhere with vector charts, costs $139 US which includes one chart region;
additional regions are $99. You can upload small sections of charts to a mapping
Garmin GPS or chartplotter. I don't know if it works at all with other brand
A final note: don't attempt this without good paper charts. There are places
in electronic charts where there is no data, as in the approach to Drummond,
and the only place you will find depths and marks is Richardson's. Then there
is the danger of relying completely on a computer ...
From Lee Haefele on The Live-Aboard List
I have discovered downside of Garmin Bluecharts on CD. Ready to add 2 new
chart areas, Garmin says I need FREE update CD, nice I think. Next I find
that to use it, even with new unlock cards, ($89 ea at Defender) I must pay
$75 extra to upgrade each old chart that I purchased 7-13 months ago.
Otherwise I can unlock more OLD charts on CD. Seems I must upgrade minimum
of one old chart area to make it accept any new updated maps for the new
unlock cards. An alternative was offered, that I buy a NEW ver 5.5 CD, not
using the "FREE update" CD. This is $139 at West Marine, but includes one
more unlock card. Nowhere are these policies explained in Garmin
literature; the first phone tech support person had no knowledge of it
either. This makes me wish that I had gone Laptop PC rather than Garmin
Chartplotter. Garmin definitely should not offer a FREE CD that has fees to
use it that are not disclosed.
Electronic chart formats:
- ARCS. (British "Admiralty's Raster Chart Service". Raster.)
- BMP. (Raster. Bitmap monochrome file.)
- BSB. (AKA "Maptech ChartKit/BSB format" ? Raster. NDI.)
- C-Map. (Vector. Available only on chips. CF-85 or CF-95/NT sizes.)
- CYC (Caribbean Yachting Charts).
- Garmin. (Vector. Available only on proprietary chips for vendor's device.
Standard and Micro sizes. Derived from Navionics.)
- Navionics. (Vector. Available only on proprietary chips for vendor's device.
Microchart and NavChart sizes.)
- NOS/GEO. (Raster. SoftChart International.)
- Passport. (Vector. Only Nobeltec VNS uses them ?)
- Transas. (Vector. Only Tsunamis uses them ?)
- S-57. (Vector. An IHO (International Hydrographic Organization) standard.)
- DNC (Digital Nautical Chart). (Vector. Proposed standard from NIMA.)
- ENC (NOAA Electronic Navigation Charts).
Raster == bigger file sizes than vector, less intelligence/layering than vector.
Non-chart data formats:
- GRIB: vectorized weather data.
Original sources of map/chart data:
Where to get electronic charts:
NOS Data Explorer
From Geza Szabo on the WorldCruising mailing list
[Re: Free charts on-line:]
Maptech's Free Boating Charts
1. Choose area
2. Chosse sub-area
3. Select show charts
4. Click view it!
Small scale charts only available for the US territorial waters.
You can also create routes with this site, and I think it is more easy to
navigate through the charts.
Large scale chart available for the whole World.
Small scale chart available for North America,
and north part of South America,
some parts of the Pacific also covered.
You can download for testing purposes digitised NOAA vector charts. You can
a navigational software for the maps. Only parts of the USA is available
yet, but this is absolutely free.
A link collections of maps around the world, not for navigation.
A lot of maps around the world (most of them are not nautical).
Making charts from Google Earth:
"Navigational charts direct from Google Earth" by Paul Higgins and Nancy Knudsen
(runs on Windows; converts a Google earth picture directly to a BSB/KAP chart)
Sarana's "How to make Google Earth Images into Charts"
(take any image file and convert it to a geo-referenced chart that you can import into your chartplotter program)
"Chartplotters for Passagemakers" article by George Day
in 1/2001 issue of Blue Water Sailing magazine
Several good letters about handheld GPS chartplotters in 11/15/2000 issue of
From Les Hall on BoaterEd
> I am trying to buy a GPS Chartplotter but struggling every step of the way.
> The chips seem very expensive (2 to 3 hundred a piece) and are more convenient
> but are they really that much better than having a CD that you download what you need ?
> I'm not worried about the convenience issue. I want to know what you get in
> the chip that you don't get in a CD.
> I have heard that you don't get a lot of depths in the CD.
I prefer the CDs for a variety of reasons:
They are a lot less expensive.
They are easily updatable.
CDs will, in the future, contain much more local information, like marinas and fuel docks.
You'll be able to update the data via downloads from the web.
You'll notice that most of the new units coming out, at least the recreational ones,
are CD based. However, the cartridges are "plug and play" and currently,
as you note, provide charts with more detail.
On-line chart viewing:
NOAA Nautical Chart On-Line Viewer
MapQuest's lat/long-to-map page
Summarized from Captn. Jack's "Electronic Charting Tip":
When planning a route, start with the largest-scale chart that will hold the
entire route. Draw the route in rough form. Then change to larger-scale charts
for each portion of the route, and move/insert waypoints to tweak the route (avoid
Summarized from Captn. Jack's "Electronic Charting Tip":
Zooming in on a chart does not provide more/better detail; changing to a larger-scale
Summarized from Captn. Jack's "Electronic Charting Tip":
Buy electronic charts, print out paper copies showing your routes,
and carry the paper copies on board as backups to the electronics.
From Glenn Duncan on Cruising World message board:
We're just back after the second seven-month cruise with electronic charts.
First off, yes, the chart drawer is chock-full of paper charts but I doubt
I'll ever go back to paper charts EXCEPT when (never say "if")
the PC-chartplotter goes belly up.
Several issues here, but I'll try to be brief. Well, semi-brief.
1. There may be outraged howls when I say the biggest advantage of
electronic charts is safety, but that's true. Electronic charting
is like plotting a new GPS position every few seconds and
calculating the COG and VMG. No human can do it that fast,
but the PC can. It's very comforting to have constant position
updates in reef country when you're not quite close enough yet
to have visual contact with the reef wall.
2. Electronic charting can be verified at any time by cross-checking
the GPS-derived position with radar fixes, compass bearings,
natural transits, depth contours, etc. It surprised me how easy
and quick it is to do those cross-checks and thus confirm the
accuracy of the plotter. I find I usually do one or more such
cross-checks every hour or so. They should be done regularly,
because the chart in use may change without making you aware of
it (depending on the plotter).
3. Route planning is not only quicker and faster, but, again, safer,
mainly because of the different technique of laying out a route.
With GPS and paper charts, you have to mark a waypoint which is,
say, 2 nm off a cape, then plot the coordinates, then transfer
the coordinates to the GPS. Multiple steps increase the potential
for human error ... what we in Oz call "finger trouble".
With electronic charting, you click the mouse to create a
waypoint off that cape. The Mark I eyeball is pretty accurate,
but the exact distance off is easy to find with a mouse-click
or two. And the waypoint is equally easy to move.
4. Electronic charting means you can save the results of eye-ball
navigation (the entrance to a reef lagoon, a river, whatever)
to the electronic chart as a mini-route. Certainly, you wouldn't
repeat the exercise entirely on electronics ... or would you?
If you were dragging in the middle of the night? ... or had to
exit the river on a foggy morning with sick or injured crew? or ... ?
Last-ditch efforts, perhaps, but still ...
5. IMHO, vector charts have it all over raster charts.
Better detail, no clunky printing which becomes giant-sized
when zoomed, smaller file sizes in the computer, etc.
6. A modern desktop LCD screen is so much better than a CRT
screen or a standard laptop LCD screen that you won't believe
the difference until you use one. And it has a small enough
desk footprint that it can fit almost anywhere. My new LCD
screen (a recent acquisition) is a Sharp T1501A, I love it,
there may well be better screens. There is a wide selection
from which to choose.
7. If you cannot navigate using the low-tech, no-power, methods (i.e.
plotting on paper charts) you need education, NOT electronic charting.
If you rely solely on a electronic device with no backup, you deserve
whatever happens to you ... and it will happen.
There are two electrically different NMEA's: NMEA 0183 uses serial-bus ASCII single-talker RS232 signalling,
and NMEA 2000 uses binary multiple-talker Controller Area Network (CAN) signalling.
Article by Ed Sherman in 3/2004 issue of Cruising World magazine
From Ed Huckins on The Live-Aboard List
NMEA is basically a single
talker, multiple listener system. You can connect all the devices
(radar/chartplotter, autopilot, cockpit repeaters, ...) to your GPS in
parallel and everything will work fine, but there is not device
intercommunication in the SeaTalk sense. You can also buy an
NMEA multiplexor if you have more than one talker, but again, this
just muxes multiple inputs into a single output for distribution to the
From Eric Thompson on The Live-Aboard List
Most NMEA compatible devices can drive 3 listeners. Some
can drive less, some more. If you are connecting to an
autopilot and a radar, neither of these needs to talk TO the
GPS unless you want the compass information from the
autopilot to go to the GPS. I think you should be able to
wire the OUTPUT from the GPS to the chartplotter, and the
autopilot, and the radar. Then decide which unit has the
most valuable information to send to your GPS and wire ONLY
that unit to the INPUT of the GPS.
Some GPS units have more than one NMEA port so you could
then wire more than one unit to the GPS thus getting the
compass info to the GPS from the autopilot AND, if you are
using a computer as a chartplotter, still be able to up and
download waypoints and routes between the computer and the
Caution: Many autopilots will not operate well with too
much data (other than what is required) coming in the NMEA
port. Try it out in safe waters before you rely on it. If
you have more than one NMEA port on your GPS, I recommend
dedicating one of these outputs to ONLY send the data the
autopilot needs to see.
From article by Nigel Calder in 11/2008 issue of Sail magazine
NMEA 2000 is not yet fully inter-operable:
display units from one manufacturer can not calibrate sending units from
Free tide program: WXTide32 (has a few
blind areas, such as the Exumas)
Free email robot that sends GRIB weather files: send an
empty message to email@example.com to get instructions.
"If you keep walking east, you will always be walking east. But if you keep walking north, you'll eventually be walking south."