Re: T&T: Navigation computer reliability
I've been working with computers since the 1950's (i.e. the Aiken Mk 2)).
One thing I've learned is that ALL computers fail, usually at the most
inconvenient time. Unless you are a repair whiz the best solution is redundancy,
as Arild suggests. Four years is not a bad lifetime for a computer,
especially one not included in a program of active maintenance. The enemy of
reliability is complexity. The military has learned that parts count provides a good
estimate of equipment reliability. What ain't there can't go wrong. So keep
things simple and provide a backup for any critical function.
Making a high reliability navigational system is easy if you go about it
the right way. First, choose the simplest navigation program that will meet
your needs. Many navigation programs include bells and whistles for
competitive marketing advantages that will never be used by the average boater. Just
make sure that it will run the NOAA charts available on a DVD. Stay away from
the programs that need dongles or dedicated chart chips.
Second, get the most basic computer that the program will run on. Marine
navigation, per se, is a relatively easy computational task. Any laptop or
small form factor computer made in the last 15 years can do it. The Apollo
space craft made it to the moon and back with computers containing less
capability than the average pocket calculator. It is the various display options
that take up the cycles.
Third, get a full hardware backup. It need not be identical to the prime
system but should run the same software. Load the software on the backup
computer, make sure it works, then store it in a dry, watertight place. I've used
a Pelican watertight camera case with good results. On portions of the
cruise where exact navigation is critical, start up the backup system and run it
in parallel with the prime system. The chances of both failing at the same
time are minimal.
Remember that the answers are simplicity and redundancy. Oh yes, keep paper
charts and a hand held GPS in a desk drawer in the very unlikely chance
that everything fails. I would have suggested a sextant and a chronometer too
but few of us have Captain Bligh's skills.
Larry Z
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Our Nav computer setup has worked well for us thus far. Here's what we
have. The flybridge has a LCD monitor on an adjustable RAM mount that
is driven from a desktop computer setup below. Also have a compact
keyboard with built-in touch pad.
The lower helm has a laptop on an adjustable RAM mount. The two
computers have separate GPS puck antennas and our Nav software is
Coastal Explorer. On the dinette near the lower helm we have another LCD
display also secured with an adjustable RAM mount. When we are running
from below I use the laptop in front of me. My wife can track our
movements on the LCD at the dinette which she enjoys. In the event of a
laptop failure we can rotate the LCD so I can clearly see it from the
helm. We also travel with a spare laptop - the newer ones sure don't
hold up like the old Toshiba's!
We often cruise in new areas with lots of small waterways and rocks and
feel this system gives us good backup and redundancy. Two computers with
their own GPS's are always online. From the lower helm I have almost
instant backup with the separate monitor. A catastrophic power failure
could knock out the desktop which is run from a large inverter. We need
to replace the APC interruptible power supply that is broken because
it could run us for about 10 minutes, and I believe also gives the
desktop power some good buffering.
Of course a lighting strike could wipe out everything and that's why we
have lots of paper charts and sharp pencils! O yeah, I keep forgetting
to put one of our hand held GPS's in a grounded metal box.
Rod & Sandra Mell
NiSa, Monk 34
Powell River, BC
LRZeitlin@aol.com wrote:
Second, get the most basic computer that the program will run on. Marine
navigation, per se, is a relatively easy computational task. Any laptop or
small form factor computer made in the last 15 years can do it. The Apollo
space craft made it to the moon and back with computers containing less
capability than the average pocket calculator. It is the various display options
that take up the cycles.
Third, get a full hardware backup. It need not be identical to the prime
system but should run the same software. Load the software on the backup
computer, make sure it works, then store it in a dry, watertight place. I've used
a Pelican watertight camera case with good results. On portions of the
cruise where exact navigation is critical, start up the backup system and run it
in parallel with the prime system. The chances of both failing at the same
time are minimal.
Remember that the answers are simplicity and redundancy. Oh yes, keep paper
charts and a hand held GPS in a desk drawer in the very unlikely chance
that everything fails. I would have suggested a sextant and a chronometer too
but few of us have Captain Bligh's skills.
Larry Z
Yea, what he said. Like I've mentioned about other spares, be sure to
actually hook up your backups and use them before you have to. For instance,
I had a backup GPS to feed the computer. When I bought the cable and hooked
it up, I realized that it would only run on it's internal batteries. I got
another cable that allowed me to power the GPS AND hook it up to the
computer.
When I actually had to use my backup laptop awhile back on one cruise, it
hooked up fine, but the alarm settings in VNS were not what they were on the
main computer, so it took some tweaking to get it to make the appropriate
noises. It really helps to go through all this ahead of time so you're not
so stressed or find that you really can't use your backup when the time
comes. Also make sure that your routes, waypoints, etc. are kept the same
between the two systems.
Keith
I've spent most of my money on boating and women. The rest I've wasted.
-----Original Message-----
Third, get a full hardware backup. It need not be identical to the prime
system but should run the same software. Load the software on the backup
computer, make sure it works, then store it in a dry, watertight place. I've
used a Pelican watertight camera case with good results. On portions of the
cruise where exact navigation is critical, start up the backup system and
run it in parallel with the prime system. The chances of both failing at the
same time are minimal.
----- Original Message -----
From: "Rod Mell" nwboater@gmail.com
We often cruise in new areas with lots of small waterways and rocks and
feel this system gives us good backup and redundancy.
REPLY
There is one thing most people keep overlooking with regards to these
electronic navigation systems.
I see endless discussions concerning fancy features and useful add-ons
like anchor alrams.
What I do not see is an awareness that every national hydrographic offices
are under fiscal restraints and as a consequence do not perform as much
field work as they once used to do.
Priority is given to commercial shipping routes, high traffic areas and
places where a grounding or worse, a sinking could cause major upset to
life ashore. This is as it should be.
But recreational boaters tend to want to get away from it all and seek
secluded anchorages far from the maddening crowd and busy ship traffic.
These are the areas that get the very lowest priority in national
hydrographic offices. Chart data is often not updated for decades.
Companies that provide electronic chart data get their raw source data
from the hydrographic offices. It would be an astronomical expense if
C-Map or Navionics or Furuno or whoever actually went and did their own
detailed surveyes of remote recreqtional anchorages and byways.
In the old days of paper charts the revenue stream from paper chart sales
helped fund the Hydrographic Offices. So where does the money come from
when no one buys paper charts any more? Tax payers generally are demanding
governments cut expenses wherever possible.
Garmin has evidently decided to conduct their own surveys of inl;and minor
waters that were not covered by the National Hydrographic Office. Good
move. But I continually hear people complain that Garmin proprietary
chips are expensive. Well gee! Where do they expect the money to come
from to conduct such surveyes if not from the sale of product?
So give a thought to just how reliable the data itself might be, not just
the cocmputer displaying the data.
regards
Arild
I see endless discussions concerning fancy features
and useful add-ons like anchor alarms.
That's because it's not the data itself that's valuable. What's
valuable are the benefits that the data can provide to you. It's the
difference between creating an engineering-based solution and a
marketing-based one. Instead of having a "product" that gives me inch-
accurate depth information, I'd rather have one that allows me to
sleep soundly. Granted, the data is important (I'm not saying that it
isn't). But what's more important is what the data can do for you.
What I do not see is an awareness that every national
hydrographic offices are under fiscal restraints
and as a consequence do not perform as much field
work as they once used to do.
Maybe it's different in the west. I've done a fair amount of cruising
with existing charts over many years in the east. The land
boundaries, rocks, and major water areas don't really change much.
What changes are some depths in shoaling areas and buoy positions.
The Coast Guard makes a major effort in reporting buoy changes every
week through LNTM. At a recent MTOA rendezvous a Coast Guard official
told me that the bulk of CG national budgets go toward buoy and light
verification, maintenance, and positioning. I'd bet that data is
pretty good.
Shoaling is another matter. But why can't we cruisers report on the
areas of concern and make that data available ourselves? I doubt
there are many hydrographic offices that are ever going to re-survey
the places where I really want to anchor. Isn't it our responsibility
to document some of this and share it?
---===
Jeffrey Siegel
M/V aCappella
DeFever 53RPH
W1ACA/WDB4350
Castine, Maine
www.activecaptain.com
The Interactive Cruising Guidebook
Our cruising blog:
http://takingpaws.blogspot.com
..
----- Original Message -----
From: "Jeffrey Siegel" jeff@activecaptain.com
because it's not the data itself that's valuable.
snip <<<<<<<<<<<<<<<<<<
But why can't we cruisers report on the areas of concern and make that
data available ourselves? I doubt there are many hydrographic offices
that are ever going to re-survey the places where I really want to anchor.
Isn't it our responsibility to document some of this and share it?
REPLY
Yes.
You just asked the exact same question I asked of the Hydrographic Office
guys who attended a Power Squadron Annual General Meeting.
The answer I received was: "Because we do not know the source of the data
provided. Nor can we validate and certify as accurate the data coming in
from the field". If we can't validate the data we can't publish it.
Yeah I know. That is enough to make just about every boater bristle with
indignation. "wadda ya mean you can't trust me to tell you the truth?
Every seasoned boater imagines themselves as a new age James Cook
navigator. <VBG>
The reality however, is that it does take some training before a person
can provide valid data in a usable form.
There are in fact several organizations doing exactly what you are
describing. Among the better known and perhaps the one of longest standing
is the Great Lakes Cruising Club. (GLCC) They provided a very similar
service as you Captain PDA program. From memory I believe the service
even predated the introduction of VHF marine radio. Charted data came on
paper placed in a 3 ring binder. Designated responsible people called
Port Captains could be found in most ports and recreational location in
the whole region. Their contact information was also provided.
I know they kept up with the times because a friend of mine was a Port
Captain and he mentioned recieving a CD of the latest chart updates for
that spring. Granted that was over 10 years ago but still it was as good
as state of the art back in '96 - '98 before we all had instant high speed
internet access complete with GoogleEarth. Many GPS receivers back then
only had 5 channel Rockwell GPS chips.
And the data they provided was way more than just depth of water. They did
provide information about marina facilities, good achorages, service shop
locations and what have you. They did conduct surveys whenever possible.
AND .... they were just as scrupelous about verifying data sent in. That was
one function of the Port Captain.
My friend and I became such frequent pests to the Hydrographic Office, they
eventually invited us to a meeting. At that meeting they decided to send us
out on the same training course given to their own staffers. (Assuming we
had the time and could get away from work that long)
Later that summer we were given a 'final exam' field test. We passed and
I'm pleased to say that our work was included in the first upgrade and
re-edition of the chart for that area that had been published in 20 years.
One of the comments made by the hydrographer in charge still sticks in my
mind. He said, the chart we publish will only reflect what is here
today. The marina we so carefully measured may double in size next year
or it may close for business.
Case in point. We were doing a revisory survey of a commercial harbor. At
the head of the inlet a road bridge cut off further progress by boat.
Unbeknownst to anybody in the chart world the power utility company had
restrung power lines some fifty or so feet downstream from the road
bridge. But the harbor wall remained as an inviting place to tie up.
Standing on the road bridge it was easy to see that even a Krogen would come
into contact with the lowest energized line. Never mind tall metallic masts
of sailboats. This information is just as crucial to boaters, as depth of
water.
The list of such things is endless. The point I want to make is that
reporting such information in accurate detail takes more than just a quick
note in Word or appended to the chart plotter display.
Either the data provided is verified as being totally accurate or else it
is worthless. You can't trust it.
If a bridge clearance is given as 32 feet, it isn't good enough to be
told approximately 32 plus or minus a few feet. Height of tide must be
factored in. And just how do you go about measuring air draft at mid
span? < smile>
So by all means get people to contribute, but if even one vital piece of
data is wrong and somebody has a serious mishap, imagine the bad
reputation that will begin circulating.
More to the point, when somebody pays several thousand bucks for a total
system and then discover the chart data is incorrect and they strike a
reef, rock or whatever, it leaves a very bad impression. Will they trust
that system again?
Hydrographically yours
Arild