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06-09-2017, 03:54
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#76
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Registered User
Join Date: Aug 2014
Posts: 589
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Re: Not another one?
Quote:
Originally Posted by El Pinguino
' As I said above he should have been looking at the plotter every 15 minutes,'
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REALLY??.
No he should have been advancing his position regularly with DR to find out where the FXXX he was going to be in !5, 30, 60 (whatever minutes time he felt comfortable with considering he had a very precious cargo aboard, namely the little kiddies).
How the hell can you clobber something that size if you are actually navigating?.
Gazing at a chart plotter is NOT NAVIGATING, no matter how regularly you do it.
__________________
Now, where's my stalker?
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06-09-2017, 03:59
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#77
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Registered User
Join Date: Aug 2013
Location: Back in Montt.
Boat: Westerly Sealord
Posts: 8,178
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Re: Not another one?
Quote:
Originally Posted by Seaslug Caravan
REALLY??.
No he should have been advancing his position regularly with DR to find out where the FXXX he was going to be in !5, 30, 60 (whatever minutes time he felt comfortable with considering he had a very precious cargo aboard, namely the little kiddies).
How the hell can you clobber something if you are actually navigating?.
Gazing at a chart plotter is NOT NAVIGATING, no matter how regularly you do it.
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Point of Order!!! That was said by some other bloke at #68... not by me!!!!
Struth Bruce... careful with your 'quotes'
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06-09-2017, 07:00
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#78
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Registered User
Join Date: Sep 2009
Location: Sydney, Australia
Boat: Farr 44 Ocean Racer - Pit crew & backup helm.
Posts: 675
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Re: Not another one?
In regard to commercial chartplotters & other electronic navigation apps like iNavx & Navionics etc it has always amazed me that no one, to my knowledge, has ever developed & released a collision avoidance feature. As incidents where sailors have come to grief due to not being zoomed in enough to show reefs or small islands etc this seems like a no brainer upgrade or feature to add. It would certainly be a great feature for a brand to have if their competitors did not have it.
It would work by detecting any obstructions like land, reef or waters of less than a pre selected depth when creating a "Goto" waypoint or a Route. As a result a large warning would be displayed on the screen & the Goto waypoint or route would not be able to be saved but you would also be able to view the danger that had been detected so you could then adjust your selected waypoint or route. Surely this would not be all that difficult to do.
Maybe the fear of litigation if such a system did not work as expected due to a bug is what has prevented its development. But this should be covered by the warning about not using this device for navigation that appears on startup. Is anyone aware if such a system already exists, if so please tell me more.
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06-09-2017, 15:31
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#79
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Senior Cruiser
Join Date: Nov 2013
Location: Port Moresby,Papua New Guinea
Boat: FP Belize Maestro 43 and OPBs
Posts: 12,888
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Re: Not another one?
Quote:
Originally Posted by Ozbullwinkle
It would work by detecting any obstructions like land, reef or waters of less than a pre selected depth when creating a "Goto" waypoint or a Route. As a result a large warning would be displayed on the screen & the Goto waypoint or route would not be able to be saved but you would also be able to view the danger that had been detected so you could then adjust your selected waypoint or route. Surely this would not be all that difficult to do.
Maybe the fear of litigation if such a system did not work as expected due to a bug is what has prevented its development. But this should be covered by the warning about not using this device for navigation that appears on startup. Is anyone aware if such a system already exists, if so please tell me more.
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Not exactly, but Navionics on my tablet & phone does something similar.
You can tell it to create an "Automatic" route between a series of waypoints and it will plot a route taking into account the above factors.
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06-09-2017, 15:36
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#80
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Moderator
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: 21,135
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Re: Not another one?
Quote:
Originally Posted by StuM
Not exactly, but Navionics on my tablet & phone does something similar.
You can tell it to create an "Automatic" route between a series of waypoints and it will plot a route taking into account the above factors.
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I dunno, Stu! I'd have a hard time trusting Navionics to set up a safe course when they seem to have missing reefs, etc on their charts!
But, didn't the original C-Maps software allow one to set a route, postulate some "safe width" and "safe depth"to be considered, and then automatically check the whole route for any spots that failed the depth criterion within that width? It has been a long time since I used that software, but that's how I remember it.
Jim
Jim
__________________
Jim and Ann s/v Insatiable II, lying Port Cygnet Tasmania once again.
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06-09-2017, 15:45
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#81
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Registered User
Join Date: Apr 2016
Location: Indonesia
Boat: Outremer 55L
Posts: 3,794
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Re: Not another one?
Quote:
Originally Posted by StuM
Not exactly, but Navionics on my tablet & phone does something similar.
You can tell it to create an "Automatic" route between a series of waypoints and it will plot a route taking into account the above factors.
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Thread drift, but I think a reasonable thought experiment. Imagine that we're all in self-driving cars. You're sitting back and relaxing, perhaps with a special beverage. Suddenly your car veers off the road, goes over a cliff, and you're dead on impact with the rocks below! What happened - you thought your self-driving car was programmed to avoid harm to you? Unfortunately for you, a school bus full of kids was coming the other way and crossed the centreline. The two self-driving brains got together and decided the lesser harm was to kill you, the lone rider, rather than killing 30 children riding in the school bus. Bummer, dude.
The point being, chart plotters can plot routes that avoid "known" dangers. The problem is that what is "known" varies on vector charts. So you still can't fully trust the safe route plotted by your chart plotter - hence the "not for navigation" warning.
Passage plan on paper or raster, it's very simple.
When on passage, use all available instruments and the mark 1 eyeball (or improved via prescription glasses, polarised lenses, night vision goggles, etc.) to verify that that your passage plan isn't leading you into unknown danger.
And pray (or whatever) that you will avoid containers, submarines, deadhead logs, sleeping whales, active volcanic seamounts, and all the other unknowable and mostly undetectable hazards that lurk in the oceans of our world.
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06-09-2017, 15:54
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#82
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Registered User
Join Date: Jun 2016
Location: New Jersey, USA
Boat: Jeanneau SO409
Posts: 624
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Re: Not another one?
I used to be a Nintendo navigator, until I went to Belize:
Toughest waters to navigate... it's shallow everywhere and Navionics was utterly useless during my charter. It was all paper charts for me
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06-09-2017, 16:02
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#83
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Registered User
Join Date: Apr 2016
Location: Indonesia
Boat: Outremer 55L
Posts: 3,794
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Re: Not another one?
Regarding keeping an eye on depthsounder when on passage I find it usually displays "---", but sometimes displays "4.1" or "119" in water I know is 1,000s of metres deep. So I certainly can't rely on a depth alarm. Is this just my sounder getting air as the hull lifts, or something else?
Regarding looking out every 15 minutes, I expect that interval depends on how fast you're going. The visible horizon when standing in the cockpit of my boat, eyes about 3m above sea level, is about 4 miles. That's 15 minutes if you're going 16 knots towards a stationary object, or 12 minutes away for a large ship going 20 knots (and even less time if you're heading right at them). Something to think about, especially if you aren't using radar and AIS.
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06-09-2017, 16:05
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#84
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Registered User
Join Date: Jun 2016
Location: New Jersey, USA
Boat: Jeanneau SO409
Posts: 624
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Re: Not another one?
Quote:
Originally Posted by fxykty
Regarding keeping an eye on depthsounder when on passage I find it usually displays "---", but sometimes displays "4.1" or "119" in water I know is 1,000s of metres deep. So I certainly can't rely on a depth alarm. Is this just my sounder getting air as the hull lifts, or something else?
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Most of the charter sailboats I've been on and my own including have depthsounders that will not show anything over 999. So, if it was a big and quick drop, mine will go from 700 to --- or blinking 700, which tells me it's over 1000 deep.
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06-09-2017, 17:30
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#85
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Senior Cruiser
Join Date: Nov 2013
Location: Port Moresby,Papua New Guinea
Boat: FP Belize Maestro 43 and OPBs
Posts: 12,888
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Re: Not another one?
Quote:
Originally Posted by Jim Cate
I dunno, Stu! I'd have a hard time trusting Navionics to set up a safe course when they seem to have missing reefs, etc on their charts!
But, didn't the original C-Maps software allow one to set a route, postulate some "safe width" and "safe depth"to be considered, and then automatically check the whole route for any spots that failed the depth criterion within that width? It has been a long time since I used that software, but that's how I remember it.
Jim
Jim
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Heading down to Cairns again next week and then coming back up in the Coral Sea Rally, so just out of interest, set waypoints at RPYC marina, just outside 2 mile/ 1 1/2 mile passage and Marlin marina and told Navionics to plot a route. Took it about 5 minutes.
It did fine getting out of PNG and in past Lizard.as far as Cooktown and from Daintree down to Cairns and in through the leads.
Between Cooktown and Daintree, it went East of the Two Way Route and did a bit of weaving through narrow gaps outside Boulder, Egret, Cairns and Endeavour reefs
Guess it didn't like the narrow passes around Gubbins and Hope Islands!
Overall, pretty good effort and it managed to avoid all the known reefs.
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06-09-2017, 17:35
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#86
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Senior Cruiser
Join Date: Nov 2013
Location: Port Moresby,Papua New Guinea
Boat: FP Belize Maestro 43 and OPBs
Posts: 12,888
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Re: Not another one?
Quote:
Originally Posted by fxykty
Regarding keeping an eye on depthsounder when on passage I find it usually displays "---", but sometimes displays "4.1" or "119" in water I know is 1,000s of metres deep. So I certainly can't rely on a depth alarm. Is this just my sounder getting air as the hull lifts, or something else?
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Thermoclines or whales?
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06-09-2017, 18:05
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#87
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Senior Cruiser
Join Date: Aug 2009
Posts: 4,033
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Re: Not another one?
Quote:
Originally Posted by Seaslug Caravan
No he should have been advancing his position regularly with DR to find out where the FXXX he was going to be in !5, 30, 60
Gazing at a chart plotter is NOT NAVIGATING, no matter how regularly you do it.
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Dude, practically speaking when offshore watch keeping in order to 'advance his position with DR' you just simply look down the route for (say) 10nm. You don't need to do anything sophisticated or a calculation. And if you are on a plotter (raster or vector) you flick the zoom a bit. None of this takes any time to do. It may look like 'gazing at a plotter' but there is (should be) actually a thought process going on rather than a blank stare and blank mind.
It is in fact one of the advantages of a plotter. You (always) know where you are on the displayed chart and your route/course line. You don't have to plot a position, removing the potential for at least one possible error.
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06-09-2017, 18:19
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#88
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Senior Cruiser
Join Date: Nov 2013
Location: Port Moresby,Papua New Guinea
Boat: FP Belize Maestro 43 and OPBs
Posts: 12,888
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Re: Not another one?
Quote:
Originally Posted by estarzinger
Dude, practically speaking when offshore watch keeping in order to 'advance his position with DR' you just simply look down the route for (say) 10nm. You don't need to do anything sophisticated or a calculation. And if you are on a plotter (raster or vector) you flick the zoom a bit. None of this takes any time to do. It may look like 'gazing at a plotter' but there is (should be) actually a thought process going on rather than a blank stare and blank mind.
It is in fact one of the advantages of a plotter. You (always) know where you are on the displayed chart and your route/course line. You don't have to plot a position, removing the potential for at least one possible error.
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Exactly!
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07-09-2017, 05:33
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#89
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Registered User
Join Date: Sep 2009
Location: Sydney, Australia
Boat: Farr 44 Ocean Racer - Pit crew & backup helm.
Posts: 675
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Re: Not another one?
Here is a link I have found about a new autorouting feature in Navionics. Has anyone noticed a feature like this in iNavx which uses the Navionics charts, if not they have some catching up to do.
https://www.navionics.com/fin/charts...k-autorouting/
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07-09-2017, 07:35
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#90
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Registered User
Join Date: Jan 2015
Location: Cebu
Boat: Cranchi Atlantique 48
Posts: 280
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Re: Not another one?
Quote:
Originally Posted by fxykty
Regarding keeping an eye on depthsounder when on passage I find it usually displays "---", but sometimes displays "4.1" or "119" in water I know is 1,000s of metres deep. So I certainly can't rely on a depth alarm. Is this just my sounder getting air as the hull lifts, or something else?
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I think it is fish...
I get this sometimes when stationary in a marina. Depth sounder goes suddenly from 20 feet to 4 or whatever ... but only for a moment.
It did make me jump the first few times .. as I also have an audible alarm for shallow depths :-)
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