Help for a navigation noob please

[captmikem]

Originally Posted by Woodland Hills

If you want to use a sextant and reduce sun or star sights, you had better be good at number-crunching or have a calculator or two or three or more onboard to help out. Don’t forget to bring enough batteries too. A small math error can have huge implications.
..

You often hear this from people who know little to nothing of celestial navigation. It is not true, you only need to know how to add and subtract. Granted you need to be able to do it using 0 thru 60 which can be confusing at first. You do not need a calculator, you simply need a pencil, paper , an almanac, a means of getting accurate time and your choice of reduction tables. (and a sextant of course). I navigated ships and yachts for many years using such tools. (I was pretty happy when the NC77 came out though.)

But, unless you are truly interested in learning it, you will do fine just learning basic navigation, plotting, piloting... and how to use your particular chart plotter.

M

[AJ_n_Audrey]

I learned celestial nav many years ago, but until I'm retired and have time to practice and re-learn the skills from 35 years ago, I'll rely on my redundant GPS-based nav software. Raymarine MFD at the helm, Garmin secondary chartplotter at the nav station below, iPad with Navionics, Garmin, and AquaMaps installed. And before I go offshore again, I'll buy a second iPad. And I have three external batteries in case of electrical issues. If the Chinese start messing about with GPS, we have much larger problems to worry about, friends. If that happens, I'll prioritize celestial nav refresher work. I do still carry some paper charts of certain areas.

[Discovery 15797]

Originally Posted by Woodland Hills

Why would anyone take the time and trouble to learn celestial navigation in 2020? Or even bother with paper charts?

If you want to use a sextant and reduce sun or star sights, you had better be good at number-crunching or have a calculator or two or three or more onboard to help out. A small math error can have huge implications.

I am sure the traditionalists will pillory me for stating the obvious, but this works for us as well as tens of thousands of others worldwide.

You're right...you're getting pilloried.

I agree with many of GrowleyMonster's points. Many "cruisers" take off without knowing even the basics of navigation.

But, you are also right...many of these people rely on the electronic systems they have aboard and it works 99% of the time. Also, I suspect >95% of boaters never venture outside the site of land or beyond familiar waters.

I suspect we've all seen boats drive up onto rocks or run hard aground. Or, an incident in Puget Sound several years ago where a cruiser plotted his course, turned on the AP, went below to join his companion, and the boat eventually broadsided a sailboat. Or a disabled boat asking for assistance that informed the USCG their position was "I am off Alki Point and there is a ferry passing to my left." My point here is that modern electronics sometimes make people lazy and ignorant. Lazy, ignorant, and stupid people are a danger on the water to themselves and others.

WRT paper charts....besides being a "back up," they also provide a big picture view much better than a chart plotter or computer screen IMHO. They are great tools for planning (esp. sitting around the dinette with companion/crew), and surveying large areas.

And you are right...it is unlikely that all my electronics will fail. Perhaps unless the boat gets struck by lightning in which case all electronics will likely be toast.

Offshore I put a basic spare GPS receiver, a sat phone, and cell phone (with celestial nav software) in a waterproof Faraday Cage bag, and keep it in the microwave oven (never used at sea). I plot my course at least every 4 hours on a paper chart. And yes, I learned many years ago to use a sextant. I rarely take it out other than on ocean crossings just to practice and reassure myself I still know how to use it.

So...for the majority of puddle-pirates, ICW cruisers, and inland sailors I agree that learning to use a sextant, or having to rely on paper charts as a back up may not make much sense....why should someone actually go through the trouble to learn navigational skills when they have 24/7 access to the internet, and can easily pull into a marina (secure their boats with 25 wraps around the dock cleat) and ask for directions?

But, for others....navigation a useful skill just like tying a proper knot.

[MJH]

Originally Posted by Intifada

Hi all, I've been perusing this subforum for a while now trying to get my head round the navigation jargon but I'm a bit stumped. I'm planning on sailing up the east coast of Australia and over to Indonesia, in the meantime I'm trying to familiarise myself with charts and routes, only I can't even understand what the different acronyms are
My head is spinning at CM93, OpenCPN, MBtiles, C-Map, Navionics, GE2KAP, OeSenc - what are they or at least what are the important things/differences to know? I'm not even sure which are proprietary names for files and which are formats (or neither).
I'm getting the impression that there are no free charts (outside a few areas like the US), is this correct? Is there no crowdsourced data?
Thanks!

Offshore navigation is a subject to be learned starting with the basics which is learning Dead Reckoning (DR). My Air Force training lasted one year and that is how we started...it was my professional career. You cannot fully appreciate the basics until you are in a situation with the loss of all navigational aides traveling at full speed (450K in my case) with any heading error very quickly taking you off your intended course. There are other techniques, or tricks if you want to call hem that, that you will also learn from a good instructor.

So, if learning navigation is your goal, start by signing up for a course wherever you are, you won't be sorry. Most basic courses these days are only a few weeks. However, in conjunction with the training you should practice as often as you can...it is a use it or loose it kind of thing initially.

From your question you are jumping in way ahead of where you should be, learn navigational basics first and then get into the rest later...everybody seems to be in a hurry these days...do it correctly and start with the basics. The quickly advancing nature of technology today is a good thing but recent articles are beginning to questioning the push manufacturers are giving newbies to go where they are not fully or properly prepared; don't become a statistic.

Good Luck.

~ ~ _/) ~ ~ MJH

[anacapaisland42]

The main thing to remember is not



"what will you do IF your electronics fail"



But



"what will you do when your electronics fail"



Bill

[boatman61]

Originally Posted by GrowleyMonster

So you are limited to CM93 charts? No Linux support? Android? Looks very convenient but those limitations are something to think about. Does the software have important features not found in OCPN? Does it cost less than a cheap USB GPS? I think it is a good concept but needs a lot more development. It is kind of hard to beat free OCPN and nearly all the charts in the world including CM93, and a cheap USB puck style GPS. Runs nicely on nearly all serious operating systems, and even runs on the $35 Raspberry Pi. Well, okay yeah you need a screen, too, but a 7" screen is pretty cheap, too. Runs nice on my old Samsung Note 3 as well as my Ubuntu laptops and RPi 3 and 4. Runs on Windows, too, I believe.



When they open up that Nimble system a bit more, and get the price down in the $30 range, it will be a very interesting system. E140 is just waaaaaaaay too much to pay for a very ordinary USB GPS and software that doesn't really do very much.



They charge money for just the software? Tsk tsk.


I will be keeping my eye out for further developments, though. It does have potential.

Its a one man operation and he does the Atlantic circle every year..
Its a GPS Puck loaded with the charts and software and integrates AIS etc.. its taken me to places from The Marmaris to Perth with no problems, and I am quite happy with Windows TY..
Did not know OpenCPN came preloaded with charts.. that was the problem way back then.. you had a free system (prone to crashing) but then needed to find charts.. No worries if a Yank but elsewhere costs $$$

[boatman61]

Originally Posted by anacapaisland42

The main thing to remember is not



"what will you do IF your electronics fail"



But



"what will you do when your electronics fail"



Bill

Same as last time it happened..
Pilot charts and dead reckoning..

[GrowleyMonster]

Originally Posted by boatman61

Its a one man operation and he does the Atlantic circle every year..
Its a GPS Puck loaded with the charts and software and integrates AIS etc.. its taken me to places from The Marmaris to Perth with no problems, and I am quite happy with Windows TY..
Did not know OpenCPN came preloaded with charts.. that was the problem way back then.. you had a free system (prone to crashing) but then needed to find charts.. No worries if a Yank but elsewhere costs $$$

OCPN doesn't come with charts. You buy or download what you need. Including CM93 if you have use for it. I like CM93 for its worldwide coverage and zero price, it is just so out of date which is no big deal in mid ocean but can be a pretty big deal inshore. Anyway so if you want to load encrypted charts you install the oeSENC plugin and then you can use your key you got from the chart vendor. Yeah it is very nice for US waters or anywhere else that the charts are free, but it will play pretty much any chart from any source. Not many exceptions. The Nimble app as I understand it works ONLY with CM93.



I don't have a problem with OCPN crashing. Well, to be fair, I have not used the winDOHs version so I can't say whether that one is crashy or not. It is a very polished and well behaved app in Android or Linux. I had assumed it worked okay in "that other" OS, too.



So if you want to spend nothing at all on charts, with OCPN, you still have the option of loading CM93. But the difference is you don't have to pay E140 for a dongle. There are USB GPS devices available for $10 or so, and the very nice GlobalSat pucks are only I think about $30. OCPN is free. Linux, FWIW, is free. Sometimes you can even score a free laptop that is too slow on Windows but will run some flavor of Linux. A step up from there is a Raspberry Pi at $35 plus whatever screen you want to use, which can also be a discarded TV monitor as long as it has a HDMI input jack. OCPN is way cheaper than the Nimble setup, and does more.


I do like the concept though, having GPS, app, and charts all on one bit of hardware. And your device is already paid for, and you are happy with CM93, so no reason for you to switch. But it would appear be of absolutely no use to a Linux or Android user or someone who wants to see large scale up to date charts on his laptop or tablet or whatever. Or someone who can't see going with the more expensive system.

[SaltyMetals]

Intifada,
I agree with most of what has already been said, Growley in particular, although i generally stick to Navionics around Europe in spite of having done the course on Celestial Nav for the Yachtmaster Ocean (which was titled by the instructor as "The Study of Heavenly Bodies" !). I Agree that a plastic sextant is good for practice but it can introduce errors that you would not get with a good metal one. And as Growley said, you would not know if you had made a calculation error or it was the inaccuracy of the sextant.

What i would like to add, if you have not read it already, is the book by Dava Sobel titled "Longitude". A wonderful read when you need a break from the 3 dimensional trig and does not need an expert to understand the calculations but shows very well how Lattitude was easy in the old days but they had no way of knowing their longitude so the book covers the search for a solution.

Best of luck.
Andrew

[dickfred]

Lots of good advice here, especially from the Monster. I took a course in celestial navigation some time ago and somehow became certified. I did not then, nor now, own a sextant.

While I was not a fan of William F Buckley Jr.'s brand of politics, I did read two of his books on sailing. One of them had a good chapter on celestial navigation that simplified it as much as the subject can be. (Buckley sailed in style - he had an MD on board as well as a piano and enough electronics to feature a full length movie on selected nights. His son commenting on one of the sails stated something to the effect "how we crossed the Atlantic with only $200,000.00 worth of electronics on board."

Fortunately a version of the Buckley stuff is available through Amazon, while there is also a YouTube version of his on this subject.

Lagniappe:

In the movie "All is Lost" The Robert Redford character, after abandoning his sailboat after a collision with large floating object, remembers he had a celestial navigation kit on board and rescues it from his life raft, just before the sailboat descends to the depths. Interesting movie about sailing. The Redford character only speaks once - it's an expletive. Other than that, no dialog or voice overs to explain his actions and thought processes.

Here's the citation from Amazon on the Buckley stuff:


:Wm F Buckley Celestial Navigation Simplified
(16)
40min
2017
16+

Hosted by John Rousmaniere teaches navigation rules, plotting bearings, chart & compass, radar, step-by-step techniques for navigating with both classic dead reckoning piloting and electronic navigation instruments.
Genres
Special Interest
Director
William F. Buckley
Starring
John Rousmaniere, William F. Buckley

Rentals include 30 days to start watching this video and 48 hours to finish once started.
Rent

SD $5.99

Buy

SD $34.99

Add to

Watchlist

[tekdiver]

Originally Posted by a.d

To cover some of the terms you brought up -

OpenCPN is open source chart plotter software - this will read charts of various types and display them in a coherent and sane manner.

oeSENC is a plugin for OpenCPN which allows you to purchase good quality vector charts. You can purchase those from the oeSENC website. Often these come from the hydrographic offices of various countries and territories. I would recommend picking up a USB dongle to tie the chart licences to as each chart can only be tied to two pieces of hardware, be it a PC or a USB dongle.

GE2KAP is a process (involving software of the same name?) of converting Google Earth tiles to a format that OpenCPN will display. I think this is useful for where there are only old nautical charts available in areas which are constantly changing. Google Earth satellite photos of only a year (or less) old may give a more up to date "idea" of what the shallow areas look like. Perhaps this might be helpful around the reefs?

Navionics is a commercial vendor of marine charts and software - if you don't want to mess around with it this may be the route you go down, but there are sometimes "inconsistencies" that arise. It's pretty straightforward to install the app on your iPhone or iPad and select the area of charts you want to download. I think it can be linked to some instruments if they can be put on the Wifi somehow.

There are some attempts at open source marine charts by the same people who make the very helpful Open Street Maps. However, last time I checked they purposefully don't include soundings, and coverage may be spotty. Personally I would be cautious about solely relying on crowd-sourced charts for navigation, the reasons I'm sure you can understand.

CM93 - it's my understanding that newer versions of the CM93 charts don't work with OpenCPN and the ones that do work may be years out of date. I don't know much about these but you can google for "CM93 OpenCPN" if you want to find out more.

I'm not experienced with anything outside of my area so I'm sure someone will help you out soon with more local knowledge with regards to pilot books etc. In terms of jargon though there is much more to come in terms of actually navigating safely to a destination.

I don't know how much experience you have but it might be worth taking at least a navigation theory course to cover the basics if this is entirely new.

That,
s some great news Hope it answered your question sure did mine. as I'm setting up to cruse the Northwest Olympia to alaska and back.

[boatman61]

Originally Posted by GrowleyMonster

OCPN doesn't come with charts. You buy or download what you need. Including CM93 if you have use for it. I like CM93 for its worldwide coverage and zero price, it is just so out of date which is no big deal in mid ocean but can be a pretty big deal inshore. Anyway so if you want to load encrypted charts you install the oeSENC plugin and then you can use your key you got from the chart vendor. Yeah it is very nice for US waters or anywhere else that the charts are free, but it will play pretty much any chart from any source. Not many exceptions. The Nimble app as I understand it works ONLY with CM93.



I don't have a problem with OCPN crashing. Well, to be fair, I have not used the winDOHs version so I can't say whether that one is crashy or not. It is a very polished and well behaved app in Android or Linux. I had assumed it worked okay in "that other" OS, too.



So if you want to spend nothing at all on charts, with OCPN, you still have the option of loading CM93. But the difference is you don't have to pay E140 for a dongle. There are USB GPS devices available for $10 or so, and the very nice GlobalSat pucks are only I think about $30. OCPN is free. Linux, FWIW, is free. Sometimes you can even score a free laptop that is too slow on Windows but will run some flavor of Linux. A step up from there is a Raspberry Pi at $35 plus whatever screen you want to use, which can also be a discarded TV monitor as long as it has a HDMI input jack. OCPN is way cheaper than the Nimble setup, and does more.


I do like the concept though, having GPS, app, and charts all on one bit of hardware. And your device is already paid for, and you are happy with CM93, so no reason for you to switch. But it would appear be of absolutely no use to a Linux or Android user or someone who wants to see large scale up to date charts on his laptop or tablet or whatever. Or someone who can't see going with the more expensive system.

A $140 one off payment for a bells and whistles program, World charts and gps is a fair price to me when you look at the price of chart packs in Europe..
Navionics is a buy in then annual subscription and I have heard folks not overly happy with them.
As for CM93 as I said, its been good everywhere I have sailed Med, Sea of Marmaris, Atlantic, Caribe, S Pacific and all round Australia and Tasmania.
Don't use Linux and only use Android for my phone, a cheap Windows 10 Notebook and I am good to go.
Knock it all you want but it serves me well.

[tekdiver]

cm93 came back on search
at 2600 bucks

[GrowleyMonster]

Originally Posted by tekdiver

cm93 came back on search
at 2600 bucks

That price is for a one year subscription to one zone, with no updates. the recent version, updated and purchased from C-Map. The charts stop working if you do not renew. The version everybody has is I believe the 2011 edition, V2. That is the one all over the www. And BTW I am not sure if V3 works on OCPN or not.

[Lepke]

New Zealand charts can be downloaded:
https://www.linz.govt.nz/sea/charts/...n-about-charts
I think Brazil, too.

American Practical Navigator can be read online, wiki, etc. Lots of easy to read nav & ocean info.
OpenCPN works as good as many paid for nav programs. Better than some I could mention.
https://opencpn.org/