Another foundering how do chart plotters get it wrong

[Rustic Charm]

Wow! I really didn't expect this simple question to turn into such a 'discussion'.

I've well and truly got my answer I was seeking, and I now understand how it's happening. Though I'm not game enough to sum that up. But I have learnt from this the following;

Always have paper charts of where I am going.
I won't overly rely on the chart plotter.
Always keep a constant eyeball.

and number one, give every solid thing that can do me harm, that aint (and is) floating a wide wide berth.

[weavis]

Originally Posted by Rustic Charm

Wow! I really didn't expect this simple question to turn into such a 'discussion'.

Just ask about anchors and you will see where a simple question will take you.

[colemj]

Originally Posted by Rustic Charm

Wow! I really didn't expect this simple question to turn into such a 'discussion'.

I've well and truly got my answer I was seeking, and I now understand how it's happening. Though I'm not game enough to sum that up. But I have learnt from this the following;

Always have paper charts of where I am going.
I won't overly rely on the chart plotter.
Always keep a constant eyeball.

and number one, give every solid thing that can do me harm, that aint (and is) floating a wide wide berth.

Given what others with experience in that area have said, I think the answer has less to do with your list and more to do with not trying to pass through that area at night regardless.

Mark

[Rustic Charm]

Originally Posted by weavis

Just ask about anchors and you will see where a simple question will take you.

na, before I purchased a new anchor last year I did a search and upon getting the results I decided it was better to ask locally.

My question about chart plotters was a little more refined than what I could find in searches though.

[weavis]

Originally Posted by Rustic Charm

na, before I purchased a new anchor last year I did a search and upon getting the results I decided it was better to ask locally.

My question about chart plotters was a little more refined than what I could find in searches though.

And for goodness sake, dont tell anyone what you got.

[Jim Cate]

Originally Posted by colemj

Given what others with experience in that area have said, I think the answer has less to do with your list and more to do with not trying to pass through that area at night regardless.

Mark

Mark, there is roughly one thousand miles of sea room to the east of Gull island and rock and reef. Most of us who pass that area at night use a small fraction of that sea room to avoid worrying about those hazards.

I simply can't understand why they cut it close... no matter what form of navigation they were using.

Jim

[rwidman]

Well, the original question -"how do chart plotters get it wrong" was answered way back. Now it's just a bunch of guys trying to impress each other. Me, I'm not impressed.

[Rustic Charm]

Originally Posted by Jim Cate

Mark, there is roughly one thousand miles of sea room to the east of Gull island and rock and reef. Most of us who pass that area at night use a small fraction of that sea room to avoid worrying about those hazards.

I simply can't understand why they cut it close... no matter what form of navigation they were using.

Jim

I agree for that particular area. I've been past there at night having never traversed it previously and I just gave about a miles clearance. But then once it get's dark I give everything a wide birth.

But I think Mark is referring to places of 'unfamiliarity' and clear obstacles, in which case I agree. I'd leave those areas until day light.

[Wotname]

Originally Posted by colemj

OK.













And last, but not least:



Mark

I think we all agree that the root cause in all the quotes you posted is the navigator, not the tools he/she uses. However it is possible that the tools are contributing factors.

In the past (pre GPS), the standard suite of navigational tools available to the navigator often returned inaccurate positional results. Part of the solution was not to rely on any one form of position fixing but rather to check one against the other and use as many as possible. Another part of the solution was to give charted obstacles a large clearance zone consistent with the perceived accuracy of your positional method.. And another was to reference what the eye could see of the real environment to the charted information and not the other way around.

These were three basic navigational tenets, part of the navigator's philosophy, it is what we learned (either formally or otherwise); in order to become proficient at this trade, one had to know this stuff.

Post GPS we now have a tool that is way more powerful in determining one position. GPS gives consistent positioning data under almost every condition almost all the time. It is many orders of magnitude better than all other (non-electronic) form of maritime position fixing. I think we all know this and never doubt that the GPS position is the best - period.

So with this great tool, how / why to grounding continue to occur - that is what Rustic Charm (as OP) and other's like Jim, question.

Originally Posted by Jim Cate

..................
I simply can't understand why they cut it close... no matter what form of navigation they were using.

Jim

Let's look at two aspects, one being the an experienced navigator and the other the in-experienced (or untrained) operator.

Experienced Navigator: In the OP's example (and many others), clearly at least one of the three tenets above were violated but why?????

What logical explanation is there for failing to observe some or all of these "rules". I along with others speculate that the GPS & Chartplotter lured or seduced the navigator into making these mistakes.

The mechanics of this have already been well explained but to recap.

1. The consistently fantastic accuracy of GPS can lead (lure?) one to forego using far less accurate means to cross check.
2. The GPS position seamlessly overlaid on the chartplotter can lead one into forgetting the accuracy of the charted information is way way less than that of the position fix thus resulting in reduced clearance zones (or perhaps not even using clearance zones.)
3. Having a chartplotter visible in front of you all the time can lead one to take this as the reference data and apply it to the outside world rather than the reverse.

They do not suggest the GPS / chartplotter are the root causes but they are logical explanations of how/why all three tenets were violated and thus they can be considered contributing factors. I realise there will be other logical explanations and I would be interested in hearing yours. However other logical explanations need not invalidate the explanations above.





In the case of the in-experienced (or untrained operator), one logical explanation is far more simple.

Newbie buys a boat and wants to go somewhere new, the local shop sells him latest chartplotter/GPS already loaded with charts. Within minutes of powering it up, he has a nice picture of his local harbour with the position of his boat clearly shown. He moves his boat out into the open waterway and and he sees the position of his boat moving ever so nicely of the display or perhaps the display is moving nicely around his boat. He looks around and sees it matches his surrounding. He reads a bit of the manual and works out the zoom and sees just how accurate the GPS derived position is. It is all very intuitive and he sees this a great way to get about and into the great unknown adventures that await him up or down the coast. What could go wrong?

Well, not has he already violated the three tenets of navigation, he doesn't even know they exist. He has never had the opportunity to learn them or be made aware of them. He didn't need to ask others or take lessons (formal or otherwise) in navigational techniques, the new box seemed to do it all for him. The real question should be "what could possibly go right". IMO, a disaster waiting to happen.

Again this is a logical explanation; there may be others.

To answer your earlier question of what should be done about it, I suggest nothing as I'm a great believer in letting the Darwinian Solution take it's course. Others are perhaps more caring; if so, then education is probably the most effective solution. Perhaps even this thread contributes in a tiny way.

Apologies to those still reading for long post

[boatman61]

Originally Posted by Wotname

I think we all agree that the root cause in all the quotes you posted is the navigator, not the tools he/she uses. However it is possible that the tools are contributing factors.

In the past (pre GPS), the standard suite of navigational tools available to the navigator often returned inaccurate positional results. Part of the solution was not to rely on any one form of position fixing but rather to check one against the other and use as many as possible. Another part of the solution was to give charted obstacles a large clearance zone consistent with the perceived accuracy of your positional method.. And another was to reference what the eye could see of the real environment to the charted information and not the other way around.

These were three basic navigational tenets, part of the navigator's philosophy, it is what we learned (either formally or otherwise); in order to become proficient at this trade, one had to know this stuff.

Post GPS we now have a tool that is way more powerful in determining one position. GPS gives consistent positioning data under almost every condition almost all the time. It is many orders of magnitude better than all other (non-electronic) form of maritime position fixing. I think we all know this and never doubt that the GPS position is the best - period.

So with this great tool, how / why to grounding continue to occur - that is what Rustic Charm (as OP) and other's like Jim, question.



Let's look at two aspects, one being the an experienced navigator and the other the in-experienced (or untrained) operator.

Experienced Navigator: In the OP's example (and many others), clearly at least one of the three tenets above were violated but why?????

What logical explanation is there for failing to observe some or all of these "rules". I along with others speculate that the GPS & Chartplotter lured or seduced the navigator into making these mistakes.

The mechanics of this have already been well explained but to recap.

1. The consistently fantastic accuracy of GPS can lead (lure?) one to forego using far less accurate means to cross check.
2. The GPS position seamlessly overlaid on the chartplotter can lead one into forgetting the accuracy of the charted information is way way less than that of the position fix thus resulting in reduced clearance zones (or perhaps not even using clearance zones.)
3. Having a chartplotter visible in front of you all the time can lead one to take this as the reference data and apply it to the outside world rather than the reverse.

They do not suggest the GPS / chartplotter are the root causes but they are logical explanations of how/why all three tenets were violated and thus they can be considered contributing factors. I realise there will be other logical explanations and I would be interested in hearing yours. However other logical explanations need not invalidate the explanations above.

In the case of the in-experienced (or untrained operator), one logical explanation is far more simple.

Newbie buys a boat and wants to go somewhere new, the local shop sells him latest chartplotter/GPS already loaded with charts. Within minutes of powering it up, he has a nice picture of his local harbour with the position of his boat clearly shown. He moves his boat out into the open waterway and and he sees the position of his boat moving ever so nicely of the display or perhaps the display is moving nicely around his boat. He looks around and sees it matches his surrounding. He reads a bit of the manual and works out the zoom and sees just how accurate the GPS derived position is. It is all very intuitive and he sees this a great way to get about and into the great unknown adventures that await him up or down the coast. What could go wrong?

Well, not has he already violated the three tenets of navigation, he doesn't even know they exist. He has never had the opportunity to learn them or be made aware of them. He didn't need to ask others or take lessons (formal or otherwise) in navigational techniques, the new box seemed to do it all for him. The real question should be "what could possibly go right". IMO, a disaster waiting to happen.

Again this is logical explanation; there may be others.

To answer your earlier question of what should be done about it, I suggest nothing as I'm a great believer in letting the Darwinian Solution take it's course. Others are perhaps more caring; if so, then education is probably the most effective solution. Perhaps even this thread contributes in a tiny way.

Apologies to those still reading for long post

Phew......

[weavis]

Originally Posted by boatman61

Phew......

Bacardi and coke all over the screen.........

[Wotname]

Originally Posted by boatman61

Phew......

Ya mean ya read it all - thanks

[Wotname]

Originally Posted by weavis

Bacardi and coke all over the screen.........

Well, what an eye opener - not sure if I would trust you as navigator, I mean "Barcadi", really - what sort of sea dog are you

Officers (including the "pencils" and 'sparks" and so on) drink gin and the ratings - rum.

[weavis]

Originally Posted by Wotname

Well, what an eye opener - not sure if I would trust you as navigator, I mean "Barcadi", really - what sort of sea dog are you

Its all the darned receptionists left in the cupboard after a very expensive christmas bash I laid on for them.......... took the stash home!

wimmin

[Wotname]

Originally Posted by weavis

Its all the darned receptionists left in the cupboard after a very expensive christmas bash I laid on for them.......... took the stash home!

wimmin

Ahh... that's different, drinking freebies (or sort of 'free' in your case) is very acceptable behaviour; welcome back to the inner circle.