From: Jim Donnelly >>Reliable Nav Software Nav System Reliability Ranking 1) Paper chart and eyeball running on Intracranial Processor 1945 Version 2) CMap on my old Echotec Green Screen relic 3) Maptech using NDI Charts 4) VNS on XP Joe Engle said: >He [Commander Beebe] might have said that when you really compare honestly and across all users, Number 1 is the most error prone. And if navigating is about safety, then that would make your #1 my number 4. I tend to agree with Jim Donnelly on this one. No question human error is a factor in many accidents or mistakes. But computers simply combine the risk of human error with the risk of computer error. People on this list have talked about their computer-based navigation systems locating their boats on dry land. Logic would tell you that a person navigating a boat would be looking ahead and would see where the plotter was taking him and make the appropriate corrections. But we probably all have heard stories of people who have blindly followed their navigation software into trouble. I've run a Beaver floatplane up and down the Inside Passage a number of times in a variety of weather conditions. There are no useful land-based navigation aids for low-flying aircraft along the coast (we rarely fly higher than 1,000 feet). So navigation has always been the finger-on-the-chart variety. Look out the window and if what you see matches where your finger is at on the chart, you're in the right place. This navigation system has never failed, frozen, crashed, or given me a "Fatal Error" message. Of course the advent of GPS has made electronic navigation along the coast much more feasible, as accurate position fixes are no longer reliant upon line-of-sight navaids like VORs. But the GPS receivers are not foolproof, and I hear just as many stories from my pilot friends about bogus GPS positions and data as I do from my boating friends. My point is that navigating all those flights with charts, eyes, and fingers has never once failed us or led us astray. The more things you ask a human to do, the greater the odds are that the human will make a mistake. So think about electronic or computer-based navigation for a moment. What does the human have to do? He or she has to remember how to follow a whole bunch of procedures to enter data, recall data, display data, and so on. How many of us navigate a boat for a living, doing it day in and day out? Not very many. So maybe once a week, or every few weeks, or a few times a year, we recreational boaters fire up our navigation systems and try to remember how to recall those waypoints or select from the list of routes, or enter data, or dim the screen, or set the time differential, or any one of a huge variety of "functions." The biggest mistake I've made in marine navigation (so far- I'm sure there are bigger ones waiting) was when I was following a Loran course before dawn in our 17' Arima and my wife kept insisting we were getting farther and farther off course into shallow water. I said, no way, the Loran says I need to steer to port to get back on course. Well, eventually it became apparent even to me by the lights on shore that I was making things worse, not better, even though I was following the steering instructions from the Loran.. The problem? We hadn't used the boat for several weeks and I'd forgotten to reverse the route before starting out. So yes, the problem was initiated by human error, but it was because I had temporarily forgotten that part of the operating process that required me to reverse the route. You don't have to remember to reverse a route in order to follow it correctly on a chart. You don't have to remember that such-and-such a function is 27 layers down in a menu when you're using a chart. The risk of making a human error is different for each one of us, but it's always there to whatever degree. So that's a given constant, if you will. But where the risk of failure is pretty much zero for a chart, it's much higher for electronic navigation, and even higher for computer-based navigation as has been testified to by a lot of posts to this list. Not only is the system itself more prone to error or failure than a chart, but the chance of human error goes up dramatically because there is so much to remember in terms of its usage. This is why I not only agree with Mr. Donnelly's list, but I would put a huge reliability gap between Item 1 and the rest of them. Don't get me wrong. I'm not knocking electronic or computer-based navigation. It's a great tool and I'm glad we have it. But I personally regard it as an aid to navigation, not our primary means of navigation. Others may feel differently. And in regard to safety, I've never heard anyone say, boy, that chart led me right into the rocks. But I have heard, and have read on this list, plenty of examples where problems, failures, or errors with electronic or computer-based navigation systems have gotten boaters into trouble. Item 1 on Mr. Donnelly's list has three elements- a chart (which is error-proof), and a set of eyes and a brain, both of which are not error proof. Understanding the shortcomings of eyes and brains and adjusting ones attitude and actions to minimize them will go a long way toward making Item 1 the most reliable and safest means of getting a boat from Point A to Point B. Note that I did NOT say "convenient." In the late 1700s, Captain James Cook--- and Jean-Francois de La Perouse...;-) ---found his way from Europe to the Pacific and to the places he wanted to go in a boat that could more or less go only one way and with charts that were largely estimates sprinkled with guesses. He and his crew did a pretty good job with their eyes and brains. So contrary to what many of us may believe today, we don' t need satellites and radio beacons and chart chips and DC power to get to Point B. And while Captain Cook had plenty of problems we can be very grateful we don't have, "Fatal Error" messages popping up on his navigation system wasn't one of them. ______________________________ C. Marin Faure 36' Grand Banks "La Perouse" Bellingham, Washington