Reflections on Seamanship

[wingssail]

Originally Posted by Palarran

I can go by a rock and look at the plotter and by golly, it shows it right exactly there. I can back into a dock, look at the plotter, and it shows me right in that marina, right in that dock space...Weather forecasts and telling the coming weather from the surroundings would be great. Storm tactics - very important...

Apparently you have not sailed in the large part of this world where the charts are off by several hundred meters, or more. Your GPS may be exactly correct but the chart shows a harbor and you eyeballs show an island far away from that.

Once you leave that sheltered existence you will have to doubt every thing the chart plotter tells you. It may be right, but it may be wrong.

As for the weather, Yep, you need to anticipate what is coming by what you see. Fortunately my wife is very good at that, me, not so much.

[Jammer]

World is full of people who can't read a map or chart


And full of people who can't use a compass and protractor to take a few bearings to landmarks and determine their location


Or know how to keep a navigation log.



Celestial is like an inaccurate GPS that only works once or twice a day. What will they do with the coordinates even if they can get them?


Why stop there? What is the guarantee that WWV will stay on the air if GPS does not? Shall we all learn to shoot lunars? How many people even could, if they really wanted to?


The lighthouses are mostly gone, the radiobeacons are completely gone, LORAN is gone, the ranges are disappearing. Navigation has depended upon shore facilities since the end of the shipwreck era

[Adelie]

Originally Posted by Jammer

World is full of people who can't read a map or chart


And full of people who can't use a compass and protractor to take a few bearings to landmarks and determine their location


Or know how to keep a navigation log.



Celestial is like an inaccurate GPS that only works once or twice a day. What will they do with the coordinates even if they can get them?


Why stop there? What is the guarantee that WWV will stay on the air if GPS does not? Shall we all learn to shoot lunars? How many people even could, if they really wanted to?


The lighthouses are mostly gone, the radiobeacons are completely gone, LORAN is gone, the ranges are disappearing. Navigation has depended upon shore facilities since the end of the shipwreck era

NIST is agitating to close down WWV & WWVH for budgetary reasons.

As long as there are charted AM stations you can fake an RDF using a radio with a ferrite bar antenna.

[Palarran]

Originally Posted by wingssail

Apparently you have not sailed in the large part of this world where the charts are off by several hundred meters, or more. Your GPS may be exactly correct but the chart shows a harbor and you eyeballs show an island far away from that.

Once you leave that sheltered existence you will have to doubt every thing the chart plotter tells you. It may be right, but it may be wrong.

As for the weather, Yep, you need to anticipate what is coming by what you see. Fortunately my wife is very good at that, me, not so much.

Ah yes, another "you don't know #$^&" sailor. I love it.

[Pelagic]

Originally Posted by Jammer

World is full of people who can't read a map or chart


And full of people who can't use a compass and protractor to take a few bearings to landmarks and determine their location


Or know how to keep a navigation log.



Celestial is like an inaccurate GPS that only works once or twice a day. What will they do with the coordinates even if they can get them?


Why stop there? What is the guarantee that WWV will stay on the air if GPS does not? Shall we all learn to shoot lunars? How many people even could, if they really wanted to?


The lighthouses are mostly gone, the radiobeacons are completely gone, LORAN is gone, the ranges are disappearing. Navigation has depended upon shore facilities since the end of the shipwreck era

To me, it is a sad comment on responsibility if a skipper cannot read or understand basic navigational concepts but I dont see that with serious cruising families.

But like any other skills, its up to the individual to decide to what level of proficiency they will aspire to.

I disagree that we have "depended" on shore side Navaids since shipwreck days.
There are many modern navaid assisted marine casualties simply because they did not verify with the available onboard tools that became "unfashionable"

[SeanPatrick]

Originally Posted by Palarran

That's funny. The slide rule part. As for your celestial nav app, there are 8 billion people out there and more than a few would either buy or use it, including me. Maybe make it so I can hold my phones camera up to the sky and it will tell me my position. Wait, it already does that. How's the app going to work with my phone? ;-)

I tried an app once that claimed to be able to take measurements using the phone's camera, but it was just way too inaccurate. The sensors in the phones are not good enough yet to get the precision you need for celnav.


The app I'm working on will be a perpetual almanac/sight reduction & DR calculator/great circle route planner/maybe more. I don't know. I'm mainly doing it for myself ... but don't think for a second that I'm not working out how much to charge for it. lol


I'll let you know when it's at least functional enough to try out.

[hpeer]

Pelagic wrote:

I have 2 quality magnetic compasses each on their own shelf a safe distance from the electronic magic.

Not how a modern designer would do it, but they are not out their when your electronic instruments stop working or give false readings for whatever reason.

Any hints on how you make that work?

[goboatingnow]

Good seamanship
“ keep her roughly on her course , and don’t hit anything while I sleep , good watch “

[NevilleCat]

US issues renewed Mariner Warning on GPS interference - MySailing.com.au

[Mr B]

If every thing fails, even the compass, I still know which direction Im going,
I know where East, South, North and West is during the day,
Just before dark, The big star in the east is visible,
That will keep me on track during the night,
In total Darkness, I will only do 25 miles approx during the night,
So Im not worried about that either, Im usually too far from the coast to worry about running aground, ,
I have an idea on approximately where I am, But that is not a concern either,
Once daylight comes, I can navigate up or down the coast by sight, Once I get close enough to see it,

[Sherpa17]

I'm surprised that in the age of electronic navigation how few people can read and use a nautical chart. My experience with electronics started in the sea service with RDF and Loran A, plotting fixes in relation to a dr course, learning to calculate set and drift with vector diagrams. It was high school math made relevant for me, down to d=r x t.
Developing good dr skills required standing a proper watch with continuous observations of every element along with timely chart notations. Seeing a passage charted out is quite different than scrolling through screens. You see more.

[mvweebles]

It's been interesting to watch this thread evolve (devolve?). "Reflections on seamanship" quickly became a discussion on reliability of GPS. In this day and age, one of the most used and ubiquitous data feeds in use. Suggesting celestial navigation skills as a just-in-case backup is akin to Meteorite Insurance. I'm not saying DR skills are not useful - I believe being able to identify and assimilate multiple data points is crucial, and that means looking at the horizon, not just a highway-view of a chartplotter.

Risk is evaluated against two axis. Impact and probability. Sudden loss of GPS while crossing an ocean would carry an impact, but most people could figure it out. May not be pretty, but they'd figure out how to get somewhere. Probability of losing GPS due to system shutdown or intentional interference? Incalculably low. Meteorite Insurance. I cannot imagine a vessel so sound and a mariner so prepared that they have mitigated all other risks and need this one final risk mitigated.

The OP also asked about weather and routing. Yet this discussion focuses on GPS failure and what to do. Risk probability vs impact of not having decent seamanship skills in weather have been more or less ignored.

There is so much more to said on this topic. Surprised the focus has been on what to do if satellites suddenly go dark. Of all the risks that good seamanship skills mitigate, that is somewhere close to bottom of the list.

Peter

[carstenb]

Originally Posted by mvweebles

It's been interesting to watch this thread evolve (devolve?). "Reflections on seamanship" quickly became a discussion on reliability of GPS. In this day and age, one of the most used and ubiquitous data feeds in use. Suggesting celestial navigation skills as a just-in-case backup is akin to Meteorite Insurance.

Risk is evaluated against two axis. Impact and probability. Sudden loss of GPS while crossing an ocean would carry an impact, but most people could figure it out. May not be pretty, but they'd figure out how to get somewhere. Probability of losing GPS due to system shutdown or intentional interference? Incalcuably low. Meteorite Insurance. I cannot imagine a vessel so sound and a mariner so prepared that they have mitigated all other risks and need this one final risk mitigated.

The OP also asked about weather and routing. Yet this discussion focuses on gps failure and what to do. Risk probability vs impact of not having decent seamanship skills in weather have been more or less ignored.

There is so much more to said on this topic. Surprised the focus has been on what to do if satellites suddenly go dark. Of all the risks that good seamanship skills mitigate, that is somewhere close to bottom of the list.

Peter

I tend to agree with you, at least insofar as serious cruisers are concerned. Reading the coming weather by looking at the clouds or combining that with a barometer is a skill that all serious sailors should develop.

While we use Predict wind and windy and download GRIB files while on passage, we can usually guess fairly accurately what weather we will see over the next couple of days by simply looking at clouds and swells.

My wife is excellent at this, I lag a bit behind

[Pelagic]

Originally Posted by hpeer

Pelagic wrote:


Any hints on how you make that work?

Not exactly sure what your asking as you are an experienced mariner.

But by having a reliable steering compass with a consistent deviation card i log headings hourly and do M to T conversions as a check on electronic derived headings..

If both my Magnetic Compasses agree, they are an independent check against the sattelite or flux compass senders.

Obviously overkill when coasting using radar parallel indexing, but offshore, with no other reference other than celestials for heading checks (azimuth, amplitudes) its nice to have 2 magnetic compasses agree.

https://youtu.be/gniRG9b5F8I

[Pelagic]

Originally Posted by NevilleCat

US issues renewed Mariner Warning on GPS interference - MySailing.com.au

Interesting article...thanks!
You have to wonder when they indicate that it has been happening at certain Chinese ports, which side has been slewing the signals as tests?