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Old 15-06-2009, 06:40   #1
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Question Charts - and Reading Them

I am working on buying my first larger boat (32') and need some help with navigation. I am surprised at the number of boat owners who only have electronics and tell me if it failed they would just turn around and come back.

I hate getting lost and while I make a living in high tech, I don't trust it will work the next time I power it up. I would like to be able to read nautical charts and while I plan to take a course, that will be months away.

What recommendations (websites, books, etc.) would you make to learn AND understand charts? Does this differ from "navigation" courses that I see? My goal is to plan a day trip, work the plan, and return without electronic navigation.

For those of you familiar with sailing on the Chesapeake Bay, what are the "must have" charts.

Finally, when it comes to electronic navigation aids, if you only had one to choose - what might it be?

Thanks in advance.

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Old 15-06-2009, 06:50   #2
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I have a chartkit that covers the whole of Chesapeake Bay. I would suggest some basic Power Squadron courses. If you're in the bay a simple hand bearing compass will suffice as you're never far from land. Take a few bearings and plot your position. In real life there's so many buoys and lights in the bay it's fairly easy to find out where you are. I think a depth sounder would be the best navigation aid.

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Old 15-06-2009, 06:53   #3
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Some 25 years ago when my wife and I were just getting started in pursuing our cruising dream we joined the US Power Squadron and took their piloting and advanced piloting courses. This was a great way to meet others as well as to learn a lot of useful skills.

Re: charts and nav aids. We always carry paper charts of the areas we are traveling even though we make heavy use of electronic aids: gps/plotter in the cockpit, pc/ cap'n nav at the chart table, + radar, speed indicator, depth and of course our eyes and basic sense's. As far as our favorite elctronic aide it was the pc/nav and is fast becoming the gps/plotter. Bluewater books and charts is a good source for purchasing materials and in addition to the USPS, the SSCA is a great way to meet fellow cruisers and learn alot.

Happy sailing

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Old 15-06-2009, 06:54   #4
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If you haven't been there yet, the NOAA Nautical chart Web site has some good information. Nautical Charts & Pubs.
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Old 15-06-2009, 06:58   #5
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Read Chapman's, and you will get tons of information on how to read charts. I always have paper out covering the same area I am using electronic charts. Speed distance, and time will get you just about anywhere once you factor in drift.......i2f
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Old 15-06-2009, 07:19   #6
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(Wow - this post certainly got out of hand - LOL)
Navigation is a complete science in itself and teaching it via the forum might be a challenge. I suggest you look for navigation courses in your area and take a familiarization course. Here are a couple of swing thoughts:

True North - The lines of longitude on a chart are aligned with true north which is different than magnetic north. True north is important as your cross different zones of magnetic variation.

Magnetic North - This is the direction the magnetic compass points. The difference between true and magnetic north is called variation. Variation is different depending on where you are on the planet. You add or subtract variation to true course to get magnetic course. Another interesting tidbit is that slowly over time the magnetic variation changes so once in a great while the charts need to be updated.

Compass Rose - On the chart you will find a compass rose. The rose is aligned with magnetic north. This simplifies things somewhat as all you have to do to go somewhere is draw a line from point A to point B and transfer the magnetic heading using a set of parallel rulers. Then in its basic sense follow the compass. The difficulty is that currents will push you off the course line as will the set caused by the sideways drift of the boat. If you sailed a continuous magnetic course you would likely find yourself down current or downwind of the destination.

Compass deviation - The compass is not perfect. A "swung" compas has had its readings on each point balanced using tiny magnets in the compass) as best as possible and the residual error is printed on a deviation card. The deviation is added or subtracted from magnetic course to get magnetic heading.

In summary - Plot a magnetic course, add or subtract deviation and then "guess" (or use scientific method) to determine the drift and set. Using a circular rule you can derive a course to steer that will allow for set and drift (which might cancel each other out BTW). Follow the planned magnetic course and update yourself with position fixes.

Fixes - A specific spot on the chart - usually where your boat is. Derived from taking bearings, celestial navigation or GPS.

Thats a very basic look at compass navigation.

Navigating by landmarks - for coastal cruising navigating by landmarks is very common.

Bearing - A magnetic direction to a know location.

Basically a shore base landmark is identified and a compass bearing is derived. The simply way to get the bearing is point the boat at the object and read the compass heading. he more elegant solution is to get a hand bearing compass and shoot the bearing by looking through the glass.

With one line you can plot the line on a chart (using parellel rulers) and you know in one dimension where you are on the chart. i.e - On that line somewhere.

Pick a second object not directinally too close to the first and shoot a bearing. When you put the second line on the chart you can identify your exact location where the lines cross.

When starting with landmark navigation I always advose people to start "really big" and then get smaller. What I mean by this is rather than trying to find a pier on the shore, or a nav buoy, look for the biggest thing on shore you can find - i.e. a mountain, a headland with a distinct shape and so forth. Coastal charts will have shore based objects and usually montains depicted.

Shoot a bearing to the big object - estimate the line on the chart and then start looking for smaller items on the shore. If you are far away shooting big objects maybe be all you need.

Ded Reckoning - Navigating, usually out of sight of land by deducing a course from current position. i.e. I know I am due West of the coast and my intended harbor. I deduce that I can sail 090 and hit the coast. But when I get there I could have been drifted north or south and don't know which way to turn. A technique is to aim off to the north or south such that you beat any set and drift. Then when reaching the coast you know which way to turn with greater certainty and you can start shooting bearings.

Cruising up or down a coast I might be ded reckoning and decide I need to sail generally north with a land mass to my west. I shoot a mountain on shore periodically to mark my progress (or not) up the coast. If I am headed for a harbor I could remain offshore until the bearing to the mountain overlays the harbor, which I may not yet be able to see. I can turn in with confidence knowing that as I get closer I can start to identify small objects (the headlands for example) as I approach.

I am sure there are lots of good book recommendations from our membership - I don't have any boating specific books as I learned my navigating as a pilot.

Weather and navigation are fascinating subjects to study. Good luck!
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Old 15-06-2009, 07:32   #7
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I second on Chapman's & Chart No. 1 which is not actually a chart but a reference for chart symbols & chart selection.
Practice dead reckoning as it's the basis for navigation (course & speed over time). After you're comfortable with that start figuring out how currents run in the Chesapeake & start to add in set & drift calculations into your DR to get an estimated position.

Get a hand bearing compass, Chapmans will help you with its use.

For an electronic aid it's hard to deny a handheld GPS's usefulness.

Navigating is a lot of fun, take your time & build your confidence. Eventually with an offshore passage there is nothing like arriving at a distant port and the confidence it inspires -- the world really is round!
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Old 15-06-2009, 07:38   #8
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See American Sailing Association: ASA Store: Coastal Navigation Manual, Solutions Workbook & DVD

And: Dutton’s Nautical Navigation - 15th Ed.

And: PRACTICAL NAVIGATION FOR THE YACHTSMAN 1ST ED 1972 SAIL (item 310043021041 end time Jul 14, 2009 12:13:50 MYT)
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Old 15-06-2009, 11:15   #9
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I took the USCG Auxilliary's Basic and Advanced Coastal Navigation courses after I'd been boating and navigating around the Chesapeake Bay and tributaries for 40 years or so. I was surprised at how much I learned.

I highly recommend it. You can look over the textbook at this LINK. This is everything you said that you're looking for, all in one place.
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Old 15-06-2009, 12:30   #10
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Most charts have basic "reading" thiungs on them, or you can get NOAA Chart 1. I did the ASA home nav study course. Was fairly cheap as long as you are someone who can learn from a book (course plus nav instructment around $120). Have Maptech chartbooks and GPS system. Find I use the charts to plan a course and the GPS to get there.I find I hardy ever look at my boat's comprass anymore as it is easier to look at the autopilot compass display. I would think if in local waters a chart and hand compass would be enough, especially if you don't mind taking a less direct route going to marker-marker etc. But a entry level GPS sure makes the travel less stressful.
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Old 15-06-2009, 12:46   #11
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I believe there is a book called " Reading nautical charts" that might be useful. As to charting programmes, I use Garmin at the helm and Tsunamis on the computer.
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Old 15-06-2009, 13:01   #12
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as to that last part of your question...

Originally Posted by Kefaa View Post
Finally, when it comes to electronic navigation aids, if you only had one to choose - what might it be?
If I were only to have one electronic navigation aid, it would be radar. It's the one aid you can't make up for with a good chart.
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Old 15-06-2009, 13:13   #13
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Two books I would suggest are the following:

"How to Read a Nautical Chart : A Complete Guide to the Symbols, Abbreviations, and Data Displayed on Nautical Charts" by Nigel Calder, International Marine, 2002.

"The Practical Pilot: Coastal Navigation by Eye, Intuition, and Common Sense" by Leonard Eyges, International Marine, 1989 (this one may be out of print but is still available in used copies).

Calder's book is very good and extremely well illustrated. He covers both US and foreign charts. He explains how charts are made and why it matters, and also has the best simple explanation I've seen of chart datums. (Part of my job involves making maps, though not nautical charts, and I can tell you there are a lot of misconceptions, poor explanations and outright misinformation in print regarding datums, projections, etc.) Calder also covers some of the potential pitfalls and problems of GPS navigation. I highly recommend it if you really want to understand charts.

Eyges is a nice little book full of illustrations of how things look from a boat vs how they are depicted on a chart. It may be out of print but I'm pretty sure you can get a copy online.
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Old 15-06-2009, 13:19   #14
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If I was limited to one electrical nav device? In a busy harbor at night or in fog....Radar. Offshore or coastal...a GPS plotter. I would not want to be without a Radar, GPS plotter, sounder or paper chart and bearing compass. Offshore, throw in a sextant and a nautical almanac.

To answer one of your other questions. Always have a paper chart as a backup to your electronic me that's just common sense. Bring along a backup battery powered GPS as well.

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Old 15-06-2009, 13:19   #15
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Aloha Kefaa,
The real title to Chapman's is CHAPMAN PILOTING Seamanship & Small Boat Handling. It will cover many things including piloting and navigation you'll have questions about and I highly recommend it. Both USCG Auxiliary and Power Squadron courses are good but I'd start with Chapman's which you can check out of a public library. If you like it, which you will, you can buy later.
Kind regards,

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