Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 11-01-2015, 13:57   #181
Registered User
 
Rustic Charm's Avatar

Join Date: Jun 2011
Location: Tasmania, Australia
Boat: Bieroc 36 foot Ketch
Posts: 4,898
Re: Another foundering how do chart plotters get it wrong

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.

__________________

__________________
Rustic Charm is offline   Reply With Quote
Old 11-01-2015, 14:00   #182
Moderator
 
weavis's Avatar

Cruisers Forum Supporter

Join Date: Feb 2014
Location: SEVILLE - MALLORCA
Posts: 10,135
Send a message via Skype™ to weavis
Re: Another foundering how do chart plotters get it wrong

Quote:
Originally Posted by Rustic Charm View Post
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.
__________________

__________________
- Never test how deep the water is with both feet -
10% of conflicts are due to different opinions. 90% by the tone of voice.
Raise your words, not your voice. It is rain that grows flowers, not thunder.
weavis is offline   Reply With Quote
Old 11-01-2015, 14:02   #183
Senior Cruiser
 
colemj's Avatar

Cruisers Forum Supporter

Join Date: Oct 2005
Location: Presently on US East Coast
Boat: Manta 40 "Reach"
Posts: 10,049
Images: 12
Re: Another foundering how do chart plotters get it wrong

Quote:
Originally Posted by Rustic Charm View Post
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
__________________
www.svreach.com

You do not need a parachute to skydive. You only need a parachute to skydive twice.
colemj is offline   Reply With Quote
Old 11-01-2015, 14:03   #184
Registered User
 
Rustic Charm's Avatar

Join Date: Jun 2011
Location: Tasmania, Australia
Boat: Bieroc 36 foot Ketch
Posts: 4,898
Re: Another foundering how do chart plotters get it wrong

Quote:
Originally Posted by weavis View Post
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.
__________________
Rustic Charm is offline   Reply With Quote
Old 11-01-2015, 14:04   #185
Moderator
 
weavis's Avatar

Cruisers Forum Supporter

Join Date: Feb 2014
Location: SEVILLE - MALLORCA
Posts: 10,135
Send a message via Skype™ to weavis
Re: Another foundering how do chart plotters get it wrong

Quote:
Originally Posted by Rustic Charm View Post
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.
__________________
- Never test how deep the water is with both feet -
10% of conflicts are due to different opinions. 90% by the tone of voice.
Raise your words, not your voice. It is rain that grows flowers, not thunder.
weavis is offline   Reply With Quote
Old 11-01-2015, 14:34   #186
Senior Cruiser
 
Jim Cate's Avatar

Cruisers Forum Supporter

Join Date: May 2008
Location: cruising SW Pacific
Boat: Jon Sayer 1-off 46 ft fract rig sloop strip plank in W Red Cedar
Posts: 11,447
Re: Another foundering how do chart plotters get it wrong

Quote:
Originally Posted by colemj View Post
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
__________________
Jim and Ann s/v Insatiable II , lying Port Cygnet, Tasmania once again
Jim Cate is offline   Reply With Quote
Old 11-01-2015, 14:43   #187
cruiser

Join Date: Feb 2008
Location: North Charleston, SC
Boat: Camano Troll
Posts: 4,669
Re: Another foundering how do chart plotters get it wrong

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.
__________________
rwidman is offline   Reply With Quote
Old 11-01-2015, 14:44   #188
Registered User
 
Rustic Charm's Avatar

Join Date: Jun 2011
Location: Tasmania, Australia
Boat: Bieroc 36 foot Ketch
Posts: 4,898
Re: Another foundering how do chart plotters get it wrong

Quote:
Originally Posted by Jim Cate View Post
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.
__________________
Rustic Charm is offline   Reply With Quote
Old 11-01-2015, 16:37   #189
Certifiable Refitter/Senior Wannbe
 
Wotname's Avatar

Cruisers Forum Supporter

Join Date: Jan 2008
Location: South of 43 S, Australia
Boat: Van DeStat Super Dogger 31'
Posts: 7,331
Re: Another foundering how do chart plotters get it wrong

Quote:
Originally Posted by colemj View Post

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.

Quote:
Originally Posted by Jim Cate View Post
..................
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
__________________
All men dream: but not equally. Those who dream by night in the dusty recesses of their minds wake in the day to find it was vanity: but the dreamers of the day are dangereous men, for they may act their dreams with open eyes, to make it possible. T.E. Lawrence
Wotname is offline   Reply With Quote
Old 11-01-2015, 16:42   #190
Freelance Delivery Skipper..
 
boatman61's Avatar

Community Sponsor
Cruisers Forum Supporter

Join Date: Jan 2010
Location: UK/Portugal
Posts: 20,203
Images: 2
Send a message via Skype™ to boatman61
pirate Re: Another foundering how do chart plotters get it wrong

Quote:
Originally Posted by Wotname View Post
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......
__________________


Born To Be Wild
boatman61 is offline   Reply With Quote
Old 11-01-2015, 16:46   #191
Moderator
 
weavis's Avatar

Cruisers Forum Supporter

Join Date: Feb 2014
Location: SEVILLE - MALLORCA
Posts: 10,135
Send a message via Skype™ to weavis
Re: Another foundering how do chart plotters get it wrong

Quote:
Originally Posted by boatman61 View Post
Phew......
Bacardi and coke all over the screen.........
__________________
- Never test how deep the water is with both feet -
10% of conflicts are due to different opinions. 90% by the tone of voice.
Raise your words, not your voice. It is rain that grows flowers, not thunder.
weavis is offline   Reply With Quote
Old 11-01-2015, 16:57   #192
Certifiable Refitter/Senior Wannbe
 
Wotname's Avatar

Cruisers Forum Supporter

Join Date: Jan 2008
Location: South of 43 S, Australia
Boat: Van DeStat Super Dogger 31'
Posts: 7,331
Re: Another foundering how do chart plotters get it wrong

Quote:
Originally Posted by boatman61 View Post
Phew......
Ya mean ya read it all - thanks
__________________
All men dream: but not equally. Those who dream by night in the dusty recesses of their minds wake in the day to find it was vanity: but the dreamers of the day are dangereous men, for they may act their dreams with open eyes, to make it possible. T.E. Lawrence
Wotname is offline   Reply With Quote
Old 11-01-2015, 16:59   #193
Certifiable Refitter/Senior Wannbe
 
Wotname's Avatar

Cruisers Forum Supporter

Join Date: Jan 2008
Location: South of 43 S, Australia
Boat: Van DeStat Super Dogger 31'
Posts: 7,331
Re: Another foundering how do chart plotters get it wrong

Quote:
Originally Posted by weavis View Post
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.
__________________
All men dream: but not equally. Those who dream by night in the dusty recesses of their minds wake in the day to find it was vanity: but the dreamers of the day are dangereous men, for they may act their dreams with open eyes, to make it possible. T.E. Lawrence
Wotname is offline   Reply With Quote
Old 11-01-2015, 17:01   #194
Moderator
 
weavis's Avatar

Cruisers Forum Supporter

Join Date: Feb 2014
Location: SEVILLE - MALLORCA
Posts: 10,135
Send a message via Skype™ to weavis
Re: Another foundering how do chart plotters get it wrong

Quote:
Originally Posted by Wotname View Post
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
__________________
- Never test how deep the water is with both feet -
10% of conflicts are due to different opinions. 90% by the tone of voice.
Raise your words, not your voice. It is rain that grows flowers, not thunder.
weavis is offline   Reply With Quote
Old 11-01-2015, 17:03   #195
Certifiable Refitter/Senior Wannbe
 
Wotname's Avatar

Cruisers Forum Supporter

Join Date: Jan 2008
Location: South of 43 S, Australia
Boat: Van DeStat Super Dogger 31'
Posts: 7,331
Re: Another foundering how do chart plotters get it wrong

Quote:
Originally Posted by weavis View Post
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.
__________________

__________________
All men dream: but not equally. Those who dream by night in the dusty recesses of their minds wake in the day to find it was vanity: but the dreamers of the day are dangereous men, for they may act their dreams with open eyes, to make it possible. T.E. Lawrence
Wotname is offline   Reply With Quote
Reply

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
For Sale: Brand New top Dollar Radars, Chart Plotters,Displays 911jimmy Classifieds Archive 2 06-06-2013 23:02
Chart Plotters Exmoor Navigation 12 21-02-2011 20:25
GPS - The Venus Fly Trap - Chart Plotters maxingout General Sailing Forum 5 20-12-2010 13:41
Cockpit Chart Plotters drh1965 Marine Electronics 16 14-04-2008 17:30
Chart plotters?? Chrisc Navigation 7 25-09-2006 17:56



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 12:34.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.