Paper Charts and Electronic Wonders

[tartansailor]

When I went to school one needed to be within 1/2 NM in order to make the grade, and to be within 1/4 NM was expected. Now if I can do it, anybody can do it. But you have to make the effort.

If you look at the plots of commercial professional Navigators back as late as the early 60's their LOPs' cross within a dot!

The most expensive part of a sextant are the smoked lenses. I have a Plath, and one can take a noon sights in the tropics with ease, which I have done.

If You can master Celestial Navigation under adverse conditions, then you will become an iron man in a plastic ship, because you will by that time have developed the confidence to handle any crisis.
That to me is the mark of a sailor.

If you do not agree with the connections above, don't go out of sight of land.
Dick

[Andy Denmark]

Having taught celestial with the Power Squadron for several years, a long time prior to modern electronics, I still have an attachment to that mode of navigation when offshore. It's a pain in the butt but there's a sensual feeling of "reality" (for lack of a better term) in plotting a tight fix -- not a lot different than the feeling you get when inhaling a whiff of tarred marline or when looking at a fine wooden boat hauled out where you can see her lines.

Still, one gives way to progress when it makes life easier. Always, in the back of your mind, there's the knowledge that -- if push came to shove -- that you can still exercise that "black art" of ages past to find your location. I well remember the first time I made a delivery (1971) when I left the sextant at home and relied entirely on the then-modern Benmar Navigator 555 RDF to make a run from Key West to Beaufort Inlet. Somehow I felt a bit naked -- like leaving home without my socks -- but relied on the "new" technology for location sailing north up the Gulf Stream. The FCC had a publication that gave the frequency and L/L of all the AM broadcast stations on the east coast and their hours of operation. By dialing them in and rotating the antenna to find the "null" for several stations one could triangulate position. There was the same sort of reaction to RDF's then from the staunch traditionalists that there seems to be to GPS now. (FWIW, I still have the Benmar-555 and it still works perfectly!)

Anyway, after several trips bringing boats back home from the SORC my crew and I simplified the RDF method to using road maps. (Before you hardcore folks keel over in shock let me state that we also used the 555 for backup.) How?? The high-rise bridges over the ICW in Florida (and at other large cities along the coast) are lighted by bright mercury vapor streetlights and at 65+ feet these lighted "arches"make oustanding landmarks from many miles offshore. (I'm sure the Florida sailors know what I mean) The trick was locating them on a chart so they could be triangulated with a handbearing compass. The standard Texaco or Exxon roadmaps (which were free at service stations back then) were excellent for this as they showed the exact locations of the bridges. The NOAA charts, because they were updated infrequently, often lacked the locations of the bridges. I think there are too many bridges now to do this with any confidence.

The first GPS I owned was an early Garmin 75 (which still works flawlessly) that showed only present position, 10 routes, maybe 100 waypoints, and a rudimentary course computer. It cost over $1,100 new in 1987 or so. Aside from the fact that it eats batteries at an astonishing rate compared to it's modern counterparts, it is dead-on accurate, reading the same as it's successors (176/C or 182-C) but acquiring a bit slower as it is only three-channel. This little handheld saved the day for us in one of the early Annapolis-Bermuda races when it located us in severe weather and was perhaps the key in our class and fleet first place finishes that year. Because of the inclement (ahem!) weather using a sextant would have been impossible.

While using a sextant on a large ship is easy, getting accurate fixes on a small sailboat leads to huge errors except in flat conditions. The movements are simply too extreme and quick to line up the horizon with confidence. Some people can do this easily -- I cannot. Dick's 1/4 mile errors could not have been done from a Typhoon I bet. I taught a celestial nav course several summers from a 27' sloop and the only times the students could get fixes closer than 5 miles was in flat calm (and I was no better).

For liability (and common sense) reasons on offshore deliveries we always use a paper chart backup to the GPS, noting L/L and time at every watch change and sometimes even more frequently. From this we project the anticipated position at the time of the next plotting mainly to see what's ahead. There's always a backup GPS or two on board and plenty of spare batteries. Should there be a "poor GPS coverage" message the paper charts are then the safety factor. No, we don't take a sextant. Most of the deliveries are east coast, meaning that recovering from being lost is a matter of heading toward the setting sun until a large continent appears.

Further offshore, well, that's another matter. Then I would take a sextant (and a book such as Mary Blewitt's Celestial Navigation for Beginners) for basic lifeboat navigation, i.e., noon sights and Polaris fixes as these are pretty much no brainers.+ The GPS augments celestial by providing absolutely accurate time references thus taking out one of the huge variables in doing sight reductions.

Anyway, as one who has undergone several iterations of navigational technology, I believe that modern GPS has made cruising possible for many who otherwise would not have set out. Could be that one day this dependence will bite them in their butts because they don't see the need for backup but for the most part the advent of GPS marks a huge improvement over anything else that's come along in the navigational arena.

Just my $.02 worth ...........
________
Cloudy Trichomes

[Dick Barthel]

Is a slide rule a fair analogy to a sextant? Like a calculator, GPS, Chartplotters, etc. allow for so much more capability.

Dick

[Neil Gordon]

Is a slide rule a fair analogy to a sextant? Like a calculator, GPS, Chartplotters, etc. allow for so much more capability.

Dick

Seems a fair comparison. We're not denying that you can get more accuracy and functionality from modern gizmos. On the other hand, batteries can be problematical when the nearest convenience store is 1000 NM away.

[tartansailor]

Neil wrote:

Seems a fair comparison. We're not denying that you can get more accuracy and functionality from modern gizmos. On the other hand, batteries can be problematical when the nearest convenience store is 1000 NM away

Or your 12v system fails.


Dick

[Joe CD MS 300]

Lets get your unbiased synopsis of the sextant usefulness debate, please. You're the one that started it.

[Jim Davis]

During my trip this summer from Annapolis to St. John, N.B. and return I primarily used a Garmin 192C for navigation. I also had current paper on deck and used it. There were several places where the Garmin failed to show detail. The information is in the unit, but the software kept it hidden. For this trip I would plan on paper, put a route in the GPS, and keep a fair DR. I have three GPS's on board and normally keep two running.

Since this trip was coastal I did not carry a sextant, but I do have several and know how to use them.

Because of the fog, RADAR was quite helpful.

[Russell]

I use my plotter, a Raymarine E80 with navionics charts extensively, its been my primary navigation everywhere so far from new england through the eastern caribbean. One exception being the bahamas where the navionics charts were so inacruate it was practically criminal, there my eyes and paper charts were my primary form of navigation.

That said, I have paper charts of everywhere I go, between the entire US east coast and the entire eastern caribbean, plus now the entire european med I have spent thousands of dollars in paper charts. To me its worth it and nessisary. I dont keep them in the cockpit however as I sail, they would get wet and ruined in quick order. I do however keep the relevent chart easily handy, ussually on the leeward setee, yes it falls on the floor when I tack, I simply go down below and move it to the other setee when done tacking. Also handy I keep a the relevent cruising guide open to the navigation related page for the area I am in or approaching, for quick reference to things the chart does not tell you (charts in the caribbean are based on surveys from the 1800s still).

I have found however, I am a rare breed these days. I would say the majority of cruisers do NOT have full sets of paper charts. Now I am talking about people doing extending cruising outside the US. US cruisers most certainly have always seemed to have full charts. But people who leave the US on extended cruises seem to be very budget oriented and one of the places most of them have cut corners is on paper charts. By far the most common method of navigation is laptop. Laptop much more so then chart plotter, because they can pirate the software, swap the electronic charts, etc and save even more money. Unfortunately in many ways though laptops are even less reliable then chartplotters, not due to accuracy, but due to failure. Of course we all know Windows isnt perfect, but laptops themselves are not designed for the marine environment, where as chartplotters are.

However, I would not go so far as to say these cruisers are completely irresponsible. They do tend to carry at least one small scale chart of the area they are in (such as the entire eastern cariibean, entire venezuelan coast, etc...) so they have paper reference in case of laptop outage, of offshore obstructions suchs as reefs, islands and oil platforms. They all also carry current cruising guides (which act as pilot books down here) which include all the harbor chartlets, important navigation information, etc... cruising guides do act easily as your paper version of large scale charts(and are often better than). So they are still I think fully equiped in the laptop breakdown situation to still accurately navigate.

Personally I still prefer to carry full sets of paper charts anyways, I actually enjoy using paper charts and on longer trips still do DR just for the fun of it (and emergency backup). Plus I have purchased a sextant for my upcoming atlantic crossing, not because I think in this day and age it is essential equipment, but because I thought I would enjoy doing it and I found a good deal on a real german made C. Plath. However in my chart purchasing for the med, I did not go as far as I did for the eastern caribbean, I would not call my set of charts 100% complete, rather then going for British Admiralty or French charts, or even DMA, I bought Imray, which are mostly small scale with some (not all) large scale insets for popular harbors. And I followed the more common way these days of buying full sets of pilot books/cruising guides for harbor and local details. Now these european cruising guides arnt cheap, $80 a pop on average. All the small scale charts of the med, plus the pilots for half of it cost over $1500 and I still have a lot more to buy. If I wanted to buy photocopied charts of the entire med, not even origonals but B&W copies of DMA charts, it would have cost me over $2000, and I would still need the pilots, now for a full set of british admiralty chart origonals for the med, without pilots, we are looking at over $5000. In the US charts are cheap, not individual ones of course, but maptech chartkits, amazing value and downright stupid to turn down. But the rest of the world hasnt come up with this kind of option, instead you have this small scale plus pilots option, and its not all bad, but still very expensive. But I still go far more into paper then most cruisers, the med is much like the caribbean, people buy 2 or 3 overall charts and the pilots only (I have about 50 charts).

As for log books, I keep a fairly good one. Position every 3 hours or so, start and end times, weather changes, etc... I keep a seperate radio log as well, the radio log I do not log calls to friends, weather broadcasters, etc... I only log calls to or from the coast guard or similar(of whatever country), plus securite calls. I log of them time, nature of call, who origonated the call and current position at time of the call. I do admit though my log book has gaps on many day hops I have made. But any trip of more then about 6 hours, is logged.

Now, when I sailed in the US as a weekender on my last boat, I honestly did not keep a logbook. Interestingly I also did not use any GPS. Having grown up boating on the chesapeake I knew it well enough (my local area at least) to be very comfortable using paper charts, my eyes and DR to get around, even though a GPS was cheap and easy to get, I did not see the point(and yes I did go aground plenty!, but those with GPS do too, shoals move!).

[Dean Abramson]

I just got my first chartplotter, a Raymarine C-80, and after figuring out the somewhat confusing interface, I really love it.

But I would never be without charts of the area where I am sailing. In fact, I am about to buy new ones of the Maine coast where I sail. I love the ability to see the "big picture" on the chart, and use it to figure out my game plan; then the plotter is great, particularly in close quarters. (To me, one drawback of charts is that sometimes if I need to find something quickly, it often will take longer than I'd like to re-locate myself on the chart. So the plotter really shines in that regard.) I keep the current chart in a plastic cover, folded and stuck under the cockpit cushions unless it is really pouring rain. To me, comparing the chart with the plotter when I am confused is a big plus; when the two agree (usually, but not always), it is a nice feeling. I find that smaller scales on the plotter are just too small, and somewhat useless except for very general reference. Yes, I can scroll around in a larger scale to see things not close by, but I then don't have the visual relationship reference I get by seeing near and far locations simultaneously on the chart; and doing the scrolling is more time-consuming than looking at the chart. And charts are just great to spread out on the cabin table and peruse and plan. Just move your head to zoom in and out.

Power can fail, and other woes can attack, so any redundancy on a boat is valuable. I am yet to sail offshore, but if/when I do, I would like to have a sextant (and know how to use it). All tools are good, and to me this is not really an "either/or" deal; anything you can bring to make your voyage safer is a plus, IMHO.

Dean

[CruiseAlong]

I have to admit, I have all three items on board. Sextant, Loran, and GPS. I am a coastal cruiser. I try to keep up my practice in all three. Why?

The GPS technology is super, but I have lost the GPS signals in the past (this was confirmed by all of the GPS units I had on board at the time). They are a low level signal device and are affected bycertain types of atmospheric conditions and interference. They are an electronic device which is good and bad. Certainlly great for getting those UT times for the sextant. Great for speed, coverage and accuracy..bad because it is not a passive device. Would I go offshore with just a GPS....no I personally would not

The loran is also a geat device. I have a Sitex 787C but have used a number of other brands. I have been using mine since 1983. A little different from the GPS as it does not have the same problem with noise immunity. It is great that the government is reinvesting in loran (new transmitters, etc.) as a parallel system to GPS. As I indicated, I was the most surprised the first time when my GPS signals disappeared and there was my loran still pumping out the readings. In many ways it has the good and bad of the GPS, Good for speed, has good coverage of GPS for coastal, not as subceptable to noise as GPS, relatively inexpensive these days for good used units (Sitex has a new combination GPS/Loran unit), great for position repeatability.

The sextant is also a super device. Like the electronic devices, bless their hearts, you need to practice with it regularly. Doing the hand calculations is important when all else fails and the available inexpensive handheld and pc programs literally gives you a line of position with minutes of a reading. Really super programs which are both accurate and a lots of fun. This really keeps your dead reckoning skills up to date too as it depends on the same type of plotting procedures. For this work I started with a Davis 25, now have a Astra IIIb, and also sport a 1943 WWII A-10A and hand sized bubble sextant. These three are all capable of taking readings inland, i.e. you don't need the horizon. The Davis and Astra need an artifical horizon accessory which is availbable. I use the A-10A for night star sightings. The star sightings allow you to take mulitiple lines of positions at a time for current positioning, unlike sun shots. Like the act of sailing, I find sextant work very rewarding and enjoyable. My accuracy has improved to within a couple of miles.

Bottom line...I think the prudent sailor should use all of the "tools" and "skills" available to them to cross checking and backup when off shore. You are out there by yourself and a single form of navigation may not be enough. If sailing with a crew, multiple members should be well versed in the actual devices on board in case the regular navigator is disabled.

[j2sailor]

My thanks to your continued input. Again, I am astonished at the intelligence and thoughtfulness of sailors. You are a rare breed. Sailors - as a whole - seem much more in tune with seeing the big picture. Perhaps it's all about patience. I hope to pass on many of your ideas on marrying traditional and high-tech navigation systems for navigation aboard small sailboats.

I had to chuckle about the sextant discussion. I love it too - although it has gone the way of so many tools. I honestly believe it still deserves a place aboard as a backup for offshore electronic-navigation.

During my years in the Coast Guard, I used this tool extensively to position aids-to-navigation (horizontal angles) before GPS took over in the mid 90's. Standards for positioning at that time were +/- 10 yards. We used two guys on the sextant. One took the left and center object, the other the center and right object.

The conning-officer maneuvered the buoy-tender onto position by a grid, hand-drawn on a maneuvering-board. The buoy position was considered to be centered over the board's cross-hair.

As the sextant angle-takers called out angles, the ship's position was plotted every few seconds and the ship was "walked" to the center of the board. Once over the center, the buoy's sinker was dropped into position and buoy released. A final round of sextant-angles was taken and plotted immediately - and we all held our breath!

It worked very well (if we were off, the pilots raised hell!). We positioned floating aids from Tampa Bay to Key West including those in the Straits of Florida up to Miami...

[Joe CD MS 300]

See Fred on Finex's comments on what he uses on his world voyage:

"Fortunately a slip mate in FLA gave me a copy of Tsunami a charting program that runs on a laptop. The program contained a detailed harbor chart for Kingston. Since then I have also been gifted a copy of C-Maps. This looks to be as good and sometimes better than Tsunami.

I have two sextants. A good metal one and one plastic. I know how to use one and did in fact navigate from Taiwan to the Marshall Islands in the mid-80's by sextant. They are both sitting snug and secure in their storage boxes in my storage shed in FLA.

These days its GPS please. Easy, cheap, reliable, accurate and fast. I have two identical units, one is a backup. They are Garmin E-Trex units, about the size of a cell phone and run for hours on two AA batteries. The one I bought, in 2004, for the purchase trip is still in use and has performed flawlessly."


Personally I don't see much risk in relying on the GPS system, especially when you have multiple units for backup. Having a unit fail is where I believe the greatest risk is. I have three on board, a permanent mount chartplotter and two handhelds.

There is so much redundancy built into the GPS system itself that some type of sudden global collapse has to be near impossible. There are 24 satellites which send out position information independently. My units always seem to be picking up the signals from 8 to 10 at any point in time. My Garmin (if I'm remembering correctly) will get into the 2-D navigation mode with signals from 2-3 satellites depending on how they are positioned.

Here are the risks of failure that I have tried to identify in my order of likelihood. Am I missing some others?

1. Dropping one overboard, stepping on it, just some unknown failure; Solution: Have multiple units on board.

2. Loss of power, batteries; Solution: Have one hard wired, keep a 12v plug adapter for another, keep more than enough batteries on board; for long journeys get a solar powered charger.

3. Gov't degrades the signal as was initially done with the system; How likely is this? I don't know but the system was still pretty accurate when it was degraded; Solution: write your congressman and do some dead reckoning to compare with you degraded fixes.

4. Gov't turns system off; Solution: Hope we haven't been attacked, write your congressman and do some dead reckoning. One of the nice things about most GPS units is that they track your position so you should have a good starting point for your DR.

[Didereaux]

[This post transferred here from the FeNix voyage thread. A response to Fred's having said he relied on two GPS's so much that he left his sextants at home!!!]

Let's see now. I am in the tropics, where the vast majority of the planets atmospheric activities are on display. ALL computer chips are highly susceptable to strong electromagnetic fields...and yet I decide to leve all non-electronic backups at home. Sorry, that just ain't prudent....sorta follows along with refitting a spade rudder onto a full keeled boat for off-shore or using Wal-Mart blem tires on your NASCAR racer.

My point is this, you could stash 101 GPS units all over the boat and if you get a lightening strike the memory chips and processor chips are toast...period! This past summer an aquaintance had his boat hit, no real damage to the boat other than a char line(s), but everything with micro-chips was fried, even the microwaves chip. A unit need NOT be plugged into anything for an electrical field of sufficient strength to destroy its delicate silicons.

[added at This time]

Dick Barthel mentioned that everything was still okay , as Fred still had his compass...I am sure Dick is aware that a compass is a dead reckoning instrument and cannot be used to find position directly(lat/lon)


g'Luk

[Mike Thompson]

I have a GPS that swings out of the cabin into the companionway on a wooden arm. It is normally switched off. I use it if I'm interested in my
speed or the estimated time of arrival or am in fog.
I use paper charts which I have covered in a lat/long grid (in pencil)
and with many route lines each marked with course and distance.
Adding these to chart is a nice winter project.
I also keep a log in a notebook with pages of blank paper. I don't tablulate
the data entries but enter them in a descriptive way. Most entries
consist of time and buoy id. In fog, I enter time to the nearest minute, course and speed as well.
I sail in Maine and there are numerous locations that enable positive
identification of where I am and I sail from one of these to the next.
I prefer to look at the coastal landscape rather than a video screen.
Mike

[John Vigor]

My point is this, you could stash 101 GPS units all over the boat and if you get a lightening strike the memory chips and processor chips are toast...period! This past summer an aquaintance had his boat hit, no real damage to the boat other than a char line(s), but everything with micro-chips was fried, even the microwaves chip. A unit need NOT be plugged into anything for an electrical field of sufficient strength to destroy its delicate silicons.

Didereaux, what if you kept a spare GPS in a tin box, that is a Faraday Cage? Wouldn't that protect the delicate circuits on the chip?

And if the lightning strike were strong enough to melt the box, youd be better off with a pair of water wings than a sextant, don't you think?

John V.
_________________

From Vigor's Rules for Life:
13. Chisholm's Second Law: "When things are going well, something will go wrong."