paper charts vs: navionic chips

[Larry H]

Brats,

One way to navigate today is to set waypoints, enter them into the GPS or chartplotter and then steer the boat to those waypoints.

Waypoints can be 'picked off' a paper chart or marked on the plotter with the cursor. If picked off a paper chart, they then have to be entered by hand into the GPS. Plotters do that for you.

The trick is in selecting those waypoints. Lets say you are going thru a narrow harbor entrance. You can set a WP right in the entrance and steer to it. But be careful if there are any hazard near the harbor entrance. I prefer to set two or three WPs, one outside in safe water, one in the entrance, and one inside the harbor. If possible they should be in a straight line.

Then, when you arrive at the outer WP, you can steer for the entrance WP and then to the inner WP, all in a straight line. This lets you evaluate current, which can cause cross track error, which could set you onto the rocks.

Always allow for errors in your position, course and the location of hazards. Trying to cut it close next to an underwater rock can turn into a disaster. If you are at all doubtful of your position, slow down or stop and evaluate the situation using all means at your disposal.

Floating nav aids(bouys) are the least reliable, they can be drug off station by shipping, or strong winds. Fixed nav aids are better.

I have found that setting a WP off a point of land or marker, or light works well. The direction to the nav aid from the WP should be 90 degrees to your course line so that when you get to the WP according to your GPS, you can visually confirm your position.

Using electronic aids is the modern way. Just be sure to check and confirm that the electronics are not leading you into danger.

El and Bill have written about Electronically Aided Collisions, where two boats on autopilot using the same waypoints are approaching each other from opposite directions. That never existed prior to GPS.

Boat safe!

Larry H

[IT-SEA-BIT-C]

well said thataway and larry,after 20+yrs using paper charts i still consider myself a student and not a pilot or even close . but even using basic speed-time -compass bearings if all failed in a thick fog i bet i could run a few patterns to find a sea buoy and get home for dinner and if i took oldgrowths bet ,he would be eating a MRE on deck of USCG rescue boat just teasing oldgrowth but i agree its usefull to atleast have some back-up and basic skill-safe navigation to all..........john

[Larry H]

Brats,

For those who think their GPS is exact, try this:

Turn on your GPS when your boat is on the trailer or tied to a dock. Set the display to show the Lat-Lon numbers and observe.

On the Lat line, the Lat is shown as degree, minutes. and decimal minutes. Like this 38*45.568. A degree of Latitude is 60 miles, a minute is 1 mile. The first number after the decimal, 5 is 5/10 ths of 1 mile, the 6 is 6/100 ths of a mile and the 8 is 8/1000 ths of a mile. A mile(Nautical) is 6000 ft so that last digit is 8/1000 or 48 feet. Each time that digit changes by one (from 8 to 9) the distance the boat has moved is 6 feet.

You may be surprised to find that your parked boat is moving around by 10 to 60 or more feet!! That wandering around is the accuracy or lack of accuracy of the GPS signal. If the second digit to the right of the decimal changes by one digit, that represents 60 feet! Sixty feet could easily put you on a rock or run you into a bouy in the fog.

Another way to see this is to put the GPS on 'track' and watch the position shift around.(while parked)

Please consider that the next time you zoom past a hazard on the water using the GPS or plotter for position.

Boat safe.

Larry H

[oldgrowth]

Larry - I agree with everything you said, but if you are in the Sound say near the shipping lanes then it gets just enough hazy/fogy so you can no longer see your land markers. You are on a bearing that parallels the shipping lane and now all you have is a compass to go by and your paper charts. You have another mile and a half to go, then you turn 90 degrees to cross the shipping lane.

I doubt 1 in 500 people here could walk the heading on flat pavement with a hand compass and be within 200 feet of their point. Now get in a boat with current, waves, wind and a little apprehension and try it. Bet you can’t come within a quarter mile of your point. I bet just about everybody here with a little practice, can do it with a chart plotter and gps.

I am not saying you go by the chart plotter without visually looking out the windows for hazards that are not on the chart.

In my other life, I had every USGS 7.5 minute and 30 minute Topographic map for the state of Washington and Oregon plus every ortho photo for the state of Washington. I had to be able to run a line in the woods over rough terrain where you can not see 20 feet in front of yourself at times and be within a foot of my destination. The only thing I had was a helper a 165 foot tape, a staff compass and my maps.

I do know the difference between grid north, true north and magnetic north. I can read close to ¼ degree on my staff compass and the pocket compass I have with me all the time (except on the boat) is accurate to within ½ degree. Most compasses people carry with them are accurate to one to two degrees at the best.

I now have all my maps and photos in one device I carry with me called a palm computer with gps capability. I use it on land and as a backup for my chart plotter and gps on my boat.

With my experience, I would not attempt to do what I laid out in the beginning of this post, without a gps and electronic charts. With them there would be no hesitation to do so.
________
Dave

[Larry H]

Dave,

I don't navigate anymore by chart and compass except to keep track and verify the GPS.

What I do is navigate by GPS using waypoints set in a non charting GPS. So I follow the course to the waypoint, distance and time to waypoint, etc. I find the waypoint info by either using waypoint books, picking the WP off the chart, or marking the WP on one trip and storing and using that WP later. I record the Lat-Lon of the waypoints that make up the routes I use on paper. My Furuno GPS instructions warns that a GPS is not a foolproof waypoint storage system. Like any electronic storage media, it can fail and wipe out the data.

I always try to look at the view out the front and compare that to the chart info. When its foggy, that doesn't work and the GPS course and compass are all I can see anyway.

I am sure that a chartplotter is a very easy way to navigate. The problem is that folks don't learn anything about the charts that are the basis of the plotter. Things that can affect accuracy, when the surveys were done, horizontal chart datum, errors caused by 'stitching' the charts together, and so on. The accuracy of a chartplotter is no better than the data used to create the chart files.

The other problem is that a $0.25 butt splice or fuse can disable the plotter and then what do you do? If the paper charts are out and sequenced for the trip, you can continue on or get to a safe position to repair the plotter, but if the charts are stowed and not ready for use, what will happen?

If a person never learns how to match the chart to the view out the window, how will they navigate if the plotter fails?
It is possible for the military to shut off the GPS system at any time. It is also possible for a solar flare to disable the GPS system.

I am not saying don't use a chartplotter, just use it with caution and knowledge and have a backup plan. A chartplotter is not a substitute for learning how to navigate. It is just another tool.

And don't forget to install a magnetic compass. A magnetic compass will work even if all your electronics go down.

Safe boatin to yah!

Larry H

[matt_unique]

[dogon dory]

Sorry, Folks - Post Deleted By Author

[journey on]

Dr. Bob,

the 7 destroyers lost on Honda Reef, north of Pt. Arguello wern't lost due to crew error, but rather a boneheaded command decision. The command of the lead destroyer insisted on ignoring some small hints from the RDF that they were in the wrong position, and told everyone to keep in his tail, in the fog, so HE could set a new speed record from SF to SD. guess what, when you ignore common sense in pursuit of vanity, you can lose big time.

When I was launching a spacecraft out of Vandenberg, I went down there and saw the memorial. Also the abandoned Coast Guard station. Sometimes we forget how navigation technology has changed since GPS came in. With radar and your GPS, only stupidity can get you into trouble (nav trouble that is, I've been married a couple of times.) Once GPS came in and Clinton took of the built in error signals, everybody know where they are, and can get an accurate speed. Compare that to Capt. Cook 200 years ago. He was happy to be within the minute.

Boris

[Larry H]

Dan,

Not trying to start an online battle here, but do you at least carry a couple of paper charts onboard?

I have experienced a hard drive failure on a computer and that blank screen won't tell you anything.

I have also experienced a battery failure and a failure in your 12v system could take out your chartplotter.

How would you cope with trying to repair an electrical failure at sea if you could not leave the helm?

Unless a paper chart blows out the window, it and a magnetic compass should be useable if all electronics go down.

[Marooned]

Someone help me, "How do you view the charts downloaded from NOAA?"

We use the small flip-chart book (9x11) and GPS while underway and larger more detailed charts for planning. Especially while in the intercoastal it is nice to have the flip charts for a look ahead at markers landmarks and places to stop or see. I usually keep the GPS zoomed in so I know depths.

Most of the time while cruising along the Gulf Coast you will be subject to running aground if you don't keep an eye on your charts and GPS.

Tuesday while transiting Lemon Bay I had a rather large and fast SeaRay pass by giving me a funny look and shaking his head, I guess I was going to slow. About three minutes later after I made the turn on the intercoatstal that he missed, I shook my head at him as he was trying to back off a sandbar.

[dogon dory]

Sorry, Folks - Post Deleted By Author

[journey on]

DogOn Dory,

You're absolutely correct: the Captain is part of the crew, and Judy keeps pointing this out. Also, the captain reports to whatever admiral is on board, and Judy also points this out. My point was that the captain didn't pay attention to navigation, but made a decision in spite of "old style" navigation. and threatened to court martial any one who didn't follow him: the other 6 destroyers. some did do navigation and tried to slow down or go out. They did get RDF signals, though not consistently. I wasn't there, but there is a good book on it. And it was on Honda reef, a good Spanish name.

If you do risk management for a living, you know about biasing estimates so you don't hit what you're trying to miss. In spacecraft, one biases a trajectory, so that, in spite of all the errors, you miss the planet (for a flyby; if you're trying to orbit the thing, that's another story.) The destroyer captain just picked the short course, ignored navigation inputs and lost his ass and career.

Nevertheless, a point of the tale, is that the "new" navigation came about so abruptly, and is so dramatic a change that anyone who hasn't done the old stuff can't understand the problem. Fog? Just turn on the radar. Where are you? Just look at the GPS, and it better be within a few feet. We took celestial navigation before we went to Tahiti. After we finished the course GPS went from $5000 to $300. We took 2 ea. I took one sight, near the Equator; it was such a pain in the rear, I never did again. Just sold the sextant at a swap meet. And it was just in the late 90's that the random error was removed from GPS and less time than that for WAAS. And cheap small boat radars aren't that old either. We finally bought one after getting stuck in the fog in the Santa Barbara Channel. Ever try to dodge a tanker in the fog? And figure out how to steer for Oxnard? When you haven't been paying attention?

Anyway the navigation problems have dramatically changed in the last few years.

Boris

[thataway]

Boris: Dan already made my point--the commander of the squadron in error made the decision to take a course based on in-experience in the use of the RDF--(a relitatively in-accurate technology, adding in that they didn't take into account the recripicol error). Basic that the commander/captain is responsiable for the mistakes made.

Marooned: The electronic U S coastal charts on the web can be accessed:
http://nauticalcharts.noaa.gov/mcd/enc/download.htm

There are a number of programs (outlined on the sites) which will read these charts.

I took the easy route after downloading some of them--and purchased a DVD for $39 which has all of these, plus the Corp of engineers charts and a viewing program.

Currently one of the best deals is a 2 DVD set at: http://www.managingthewaterway.com/charts.htm

All available NOAA Raster Navigational Charts (RNCs), organized by region:
2. All available NOAA vector Electronic Navigational Charts (ENCs).
3. All available USACE vector Inland Electronic Navigation Charts (IENCs).
4. Free and trial versions of PC and Macintosh charting and navigation software.
5. Government publications, reference texts, and nautical calculators in searchable
Adobe Acrobat PDF format including:
• American Practical Navigator (Bowditch)
• Atlas of Pilot Charts North Atlantic Pub. 106
• Canadian Coast Guard Radio Aids to Navigation
• Chart No. 1
• Distances Between Ports Pub. 151
• Distances Between U.S. Ports (and a number of other publications)
Plus comes with Sea Clear (shareware navigation program)

I keep the DVD data on my hard drive, plus carry the DVD, if for some reason the data were to be lost. It is handy for looking up places we talk about on this and other forums, as well as Distances between US ports for planing purposes.

You can obtain the US topographical charts on CD and DVD. There are some interactive Topographic maps free on the internet, but I don't believe to the extent or detail that the nautical charts are available--maybe Dave has some better information on downloadable or cheap topo maps. To my knowlege Fugawi is one of the best of the topo's at $50 for the entire US at 1: 100,000 scale. I believe that it is considerably more expensive to get the more detailed 1: 24,000 scale maps for each state.

Another good source we haven't really fully explored yet, is Google Earth. I find it very helpful when planning--and even have copied screen shots for areas I want to explore. Also in rivers which are not well charted Google Earth gives some very good information--and one can make up their own charts.

[Marooned]

Thanks, Bob

I haven't had any problem downloading the charts. Its the viewer I could not find. I searched the NOAA site for a couple of rainy hours this afternoon, but no mention of software to read them. Microsoft told me to download a dictionary software program?? Thanks for the links.

I use google earth also, most of the coast has high enough definition that you can even find the boat ramps, etc.

[dogon dory]

Sorry, Folks - Post Deleted By Author