Reflections on Seamanship

[Bycrick]

Perhaps I might be able to sail from Hawaii to SF by knowing where the sun rises and sailing until I run into something. But going the other way is a little different. Remember that Magellan sailed all the way across the Pacific from the tip of South America Pacific and missed everything until he got to the Philippines about 4 months later. That kind of navigation can lead to starvation, scurvy. With plastic and steel rigging, one can’t even chew on the chafing gear any more.

[SeanPatrick]

Originally Posted by requiem

... you might not have a sextant and almanac with you, but if you possess the underlying knowledge you should still be able to do basic latitude sailing from your last DR position if things go really wrong.

It's the knowledge that makes the difference between knowing how to navigate and simply blindly following what the device or the checklist says.

Indeed.

[Mr B]

Originally Posted by Bycrick

Perhaps I might be able to sail from Hawaii to SF by knowing where the sun rises and sailing until I run into something. But going the other way is a little different. Remember that Magellan sailed all the way across the Pacific from the tip of South America Pacific and missed everything until he got to the Philippines about 4 months later. That kind of navigation can lead to starvation, scurvy. With plastic and steel rigging, one can’t even chew on the chafing gear any more.

Thats quite easy to do in the south Pacific, There isnt much land in it, Or Islands,
If he missed the Phillipines, He would have run into either China or Australia,
If he sailed under Australia, Then he would probably perished on his way to Africa, There isnt much land in the Indian Ocean either,

[hpeer]

Originally Posted by Pelagic

Without looking at your compass installation, its hard to say what's causing this extreme deviation, but certainly sounds like electrics.

The other part is the ability to place compensating magnets on the 4 quadrants to nullify the structural magnatism

Yeah, I thought electrics also, but I sure can not ID a source. What gets me is how much it can shift.

I have heard of electronic compass’, the one I looked up was very expensive.

Anyway, thanks for the answer.

[jackdale]

If you have read Adrift by Steve Callahan, you can determine your position with three pencils held together with elastic bands and a chart with a compass rose for latitude, and a DR for longitude.

[Don C L]

Originally Posted by jackdale

If you have read Adrift by Steve Callahan, you can determine your position with three pencils held together with elastic bands and a chart with a compass rose for latitude, and a DR for longitude.

What's a pencil?

[Mr B]

Originally Posted by Don C L

What's a pencil?

Pencil, Thats modern technology,

Its an advancement on slashing your wrist and writing in blood with a stick,

[Dsanduril]

Appropriate for this thread I suppose, navigator to young newbie sailor - “fetch me the pencil”. Young sailor thinking to self - “mains’l, stays’l, what the **** is the pens’l?”

[Pelagic]

Originally Posted by Don C L

What's a pencil?[emoji3]

It's what a constipated mathematician uses.

[endlesspursuit]

Originally Posted by Manateeman

The Weems and Plath circular rule is wicked good. Never sail without it.
I don’t stand outside in weather gear">foul weather gear but this Captain definitely know what makes sense at sea. All the manatee are doing hats off to him.
This one item is the perfect example of why simple things don’t produce electronic fog.
Tragic story, but remember the flight that descended into the Everglades?
Everybody in the cockpit was mesmerized by a faulty light and no one was watching the big picture as the altimeter spun down and they crashed killing everyone.
Electronic fog is when you loose situational awareness due to an issue with any electronic device. Killed a lot of people.
Love that old plastic speedy solution finder.
Hats off to the Captain. Happy trails to you
Captain Mark and his bookish manatees.

And remember the lost flight over the bahamas during WW2. From altitude you can see both. What happened?

[alaskasail]

• Practice-Practice-Practice
• *Tuned* Radar - leave it on all day and look at and remember what it's seeing.
• Properly calibrated depth sounder
• Charts
• Backups
• Practice-Practice-Practice

[Adelie]

Originally Posted by Manateeman

. .....
Tragic story, but remember the flight that descended into the Everglades?
Everybody in the cockpit was mesmerized by a faulty light and no one was watching the big picture as the altimeter spun down and they crashed killing everyone.
Electronic fog is when you loose situational awareness due to an issue with any electronic device. Killed a lot of people.
.....

ValuJet-592 crashed because of a fire in the hold.
https://en.m.wikipedia.org/wiki/ValuJet_Flight_592

Eastern-401 crashed due to flight crew Being distracted by a burned out landing gear light.
https://en.m.wikipedia.org/wiki/East...nes_Flight_401


That’s not to say that there aren’t plenty of examples of aircraft crashing due to pilots losing situational awareness due to electronics.

[pendragon]

Well if they hack or shut down the US GPS system , we still have Galileo and glonass and Beidou which gives even greater accuracy than GPS.

[betwys1]

Originally Posted by Pelagic

This is an open discussion on the wonderful evolution of electronic navigation, weather routing technology, modern designs focusing on speed versus storm survivability.

For some modern sailors who are dependent on the reliability of this technology continuing, while they are crossing oceans, .... what advice would you give them as a minimum backup of the arts of navigation and weather routing if global tensions turned off the civilian satellite networks and GPS?

There are at least four global sat based nav systems: GPS (US), GLONASS (Russia), Galileo (EU), BeiDou (China).
Expecting four national bureaucracies to synchronize a disable command at similar times is probably unreasonable. Having a navigator capable of using any or all of these systems is belt & braces/suspenders insurance.
Brian W

[john manning]

When it comes to electronic navigation I have always believed (assumed) my GPS was more accurate than my sextant. Best sextant accuracy I have ever achieved is 3-4 miles from my actual position. So the challenge wasn't very great for the GPS.

However I have found electronic charts very inaccurate at times (maybe that should be in places).

When sailing near to land I have learnt that cross checking with more than one information source is sensible and to always use your eyes to check what is really ahead is the same as that shown on the chart. Not just what is under the boat but what is ahead of it as well.