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05-08-2017, 09:40
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#241
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Registered User
Join Date: Jun 2015
Posts: 9
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Re: Leopard 46 lost in French Polynesia - stunning rescue pictures
In the interview, the helmsman is fairly adamant that he had set his chartplotter t display blue color for depths > 200 ft. His plan was to hug the coastline to avoid an uncomfortable sea state while staying within the blue contour.
I don't really want to pile on the guy and his family and I certainly have some sympathy for the personal and economic loss. I think fxykty above kind of expressed a sentiment I share.
The problem with his passage plan (such that it was) is that it was preset to deny him searoom and time to deal with any abnormal circumstance. I understand that there's an element of surrealism that must accompany that loss of property. I get that. I also get a little disturbed by the passive tone in which he described watching his depth sounder mark the rising sea bed. He let the boat get in front of him.
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05-08-2017, 11:10
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#242
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Registered User
Join Date: May 2015
Location: Dubai
Boat: 450S
Posts: 188
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Re: Leopard 46 lost in French Polynesia - stunning rescue pictures
Volvo Ocean Race? I don't think so :whistling:" target="_blank">http://Insurance-IRJDSUNE9932123321222xxeww-for-IRJDSUNE9932123321222xxeww-a-IRJDSUNE9932123321222xxeww-Volvo-IRJDSUNE9932123321222xxeww-Ocean-IRJDSUNE9932123321222xxeww-R...so-IRJDSUNE9932123321222xxeww-:whistling:
Sorry Sailor whats your point? the risk of a race team is underwritten by a sponsor, same as insurance. Mapfre probably get a better deal I suspect. For those that follow the gps remember its a determanistic position. The receiver is constantly saying im here, no over here, actually over here...several times a second and will discount those positions it determines as "unreasoneable". Do you know what the tollerance is on the reasonableness? I would suggest not on a $10 app and an iPad. Thus the need for secondary navigation from another source.
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05-08-2017, 12:00
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#243
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Registered User
Join Date: Jul 2010
Location: Fr. Poynesia
Boat: Southern Cross 35' Cutter - FrPol & H-boat 26' - Sweden
Posts: 245
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Re: Leopard 46 lost in French Polynesia - stunning rescue pictures
Quote:
Originally Posted by Prairie Chicken
The helmsman was an airline transport rated pilot. Pilots are taught from day one to trust their instruments. Instrument pilots, even more so. I suspect this training and background, either consciously or subconsciously, contributed to his error.
(I might point out that aviation charts are a great deal more reliable than many marine charts.)
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Yeah, that may explain something. Still, in trusting one's instruments ( note plural) as opposed to a single one, like a depth sounder, whch is useless on the drop off of a fringing coral reef.....
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05-08-2017, 13:59
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#244
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Moderator Emeritus
Join Date: Oct 2013
Location: Jacksonville/ out cruising
Boat: Island Packet 38
Posts: 31,351
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Leopard 46 lost in French Polynesia - stunning rescue pictures
We all make mistakes from time to time as we are human.
99% of the time by Luck nothing bad happens.
This time something bad happened. I'd guess he let his guard down, wasn't as diligent as he should have been, the weather was good, boat running fine etc. and it bit him
Learn from it, but don't make the mistake most do, that I am better than that, it couldn't happen to me.
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05-08-2017, 19:25
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#245
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Registered User
Join Date: Apr 2013
Posts: 931
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Re: Leopard 46 lost in French Polynesia - stunning rescue pictures
Quote:
Originally Posted by sailormed
Reading this it seems it is un "uncharted reef", but ONLY on Navionics charts!!!
What is the legal responsability of the chart supplier if this is the case?
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NEVER trust a single set of chart datum.
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05-08-2017, 20:32
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#246
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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: 21,154
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Re: Leopard 46 lost in French Polynesia - stunning rescue pictures
Quote:
Originally Posted by SecondBase
NEVER trust a single set of chart datum.
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If you will look back to the early part of the thread, the actual position of the wreck was shown on three different chart systems, including Navionics. ALL THREE showed the boat ON THE REEF, not on some apparently open bit of sea.
This is not a case of hitting an uncharted shoal or reef. They hit the well charted fringing reef at the south end of Huahine. Arguments are now centered around the presentation of the charts depths, colors, spacing of contour lines, etc, and there could be some merit in them. However, operator error seems a more rational explanation.
The hearsay statements attributed to the French navy folks don't seem to say that there are uncharted reefs, and examination of the satellite photos don't suggest the existence of such. I'm suspicious of the five yachts a year number, for we surely would be hearing of at least some of those losses and we haven't AFAIK. Attributing them all to faulty Navionics charting is even less credible IMO. Good navigators would never approach that reef in he dark at a distance where charting or GPS inaccuracies would be an issue. If they had used even a one mile standoff distance, this would never have happened.
BTW, I am not an employee of, user of or fan of Navionics. I just don't like seeing their product, which seems to have been accurate to the same degree that all the other available charts are (all having derived from the SHOM French charts) being blamed for this unfortunate event.
Jim
__________________
Jim and Ann s/v Insatiable II, lying Port Cygnet Tasmania once again.
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06-08-2017, 04:01
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#247
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Senior Cruiser
Join Date: Aug 2009
Posts: 4,033
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Re: Leopard 46 lost in French Polynesia - stunning rescue pictures
I'v looked into the Navionics chart a bit more. . . . and let me modify my position a little.
It displays perfectly on their web app. So, we know Navionics have the correct data.
And even on phone/tablet, the nearby islands display perfectly.
However, on a phone/tablet (iNavX & Navionics own app) there is definitely some sort of issue specifically on the lower half of Huahine. That is with a march 2017 chart update (the latest I believe).
In this 'funny' area (just only/specifically the southern end of Huahine), two things are odd. One is that the depth contours (which you can see in detail if you toggle to 'sonar' mode) are not shaped the same as (correctly shown) on the web app, and the other is that the drying depth's for the reef do not appear (there is no green depth layer).
It appears that there is a different chart data file being used by the phone/tablet apps than the main navionics data file (displayed on their web app).
So for folks navigation with ipads, I can in fact see how they might get into trouble here if they try to cut it close (and not give it safe margin). There is something here which Navionics should fix, and should be able to fix easily and quickly because they already have a correct data file.
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06-08-2017, 05:47
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#248
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Registered User
Join Date: Jul 2011
Location: St. Petersburg, Florida
Boat: Leopard 39
Posts: 860
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Re: Leopard 46 lost in French Polynesia - stunning rescue pictures
Quote:
Originally Posted by Group9
If I am driving along and my car's gps tells me to make a right turn, I don't think I can blame my GPS f I fail to actually establish that there is a road there first, before turning
Likewise, I would never navigate my boat at night close to a reef based on any GPS datum chart. Daylight and the mark 1 eyeball are your best reef navigation tool.
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One day I drove to Atlantic City and set a go-to waypoint of the hotel's street address, which was "something-something Boardwalk." When we got there, the GPS was telling me to make a turn directly ONTO the Boardwalk.
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06-08-2017, 06:18
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#249
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Registered User
Join Date: Sep 2008
Posts: 400
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Re: Leopard 46 lost in French Polynesia - stunning rescue pictures
Quote:
Originally Posted by Prairie Chicken
The helmsman was an airline transport rated pilot. Pilots are taught from day one to trust their instruments. Instrument pilots, even more so. I suspect this training and background, either consciously or subconsciously, contributed to his error.
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Just to be fair to pilots (and their instructors), that teaching is meant to apply when you can't see out the window. This is meant to keep you from killing yourself as a result of erroneous sensory inputs the primitive brain generates when it doesn't have a horizon. In good weather, it's heads-up all the time.
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06-08-2017, 06:55
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#250
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Senior Cruiser
Join Date: Aug 2009
Posts: 4,033
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Re: Leopard 46 lost in French Polynesia - stunning rescue pictures
Navionics main file (which is correct):
Navionics file being used on ipads (and such), with extra sounding details turned on
You can see that the depth contour 'peak' is much more to the west (past point Tiva) in the main/correct file, while it is to the east under the pass entrance in the tablet data file. That is an odd error, I'm not sure how it could happen.
The stick marks, which are on drying reef, are shown in the correct locations on the tablet file, but shown (the two west most ones) in relatively deep water.
ps. here is the webapp chart with the sonar detail turned out, as a direct comparison to the ipad display above.
I have sent a 'high priority' note explaining the issue to a contact I have at Navionics.
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06-08-2017, 07:25
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#251
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Registered User
Join Date: Apr 2013
Posts: 931
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Re: Leopard 46 lost in French Polynesia - stunning rescue pictures
Quote:
Originally Posted by daletournier
Yes, I run sas planet side by side with opencpn, its seriously awesome. I also use navionics, my belief is you can't have to much information.
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That's the way! There could be a problem in a few different areas: chart datum, rendering app and/or device. By running redundant systems you buy yourself some boat luck. It also helps keep the on watch engaged.
By running multiple systems you can also maintain situational awareness - one device is zoomed out for planning view another device is dialed in close for situational nav view.
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06-08-2017, 07:42
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#252
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Registered User
Join Date: Dec 2005
Location: Cat in New Zealand, trawler in Ventura
Boat: 46' custom cat "Rum Doxy", Roughwater 41"Abreojos"
Posts: 2,044
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Re: Leopard 46 lost in French Polynesia - stunning rescue pictures
Thanks for that, Evans. I think your comparison goes a long way towards explaining how they ended up on the reef, assuming they (and others?) were using the phone app. I have always preferred raster charts, when available, for this very reason. They lack the whiz-bang features of vector charts, but you know that the information on the chart has not been altered from the original.
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06-08-2017, 13:37
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#253
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Marine Service Provider
Join Date: Nov 2008
Posts: 482
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Re: Leopard 46 lost in French Polynesia - stunning rescue pictures
Does anyone know if the cat has been removed from the reef ?
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06-08-2017, 13:53
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#254
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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: 21,154
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Re: Leopard 46 lost in French Polynesia - stunning rescue pictures
Quote:
Originally Posted by estarzinger
Navionics main file (which is correct):
Attachment 153526
Navionics file being used on ipads (and such), with extra sounding details turned on
Attachment 153527
You can see that the depth contour 'peak' is much more to the west (past point Tiva) in the main/correct file, while it is to the east under the pass entrance in the tablet data file. That is an odd error, I'm not sure how it could happen.
The stick marks, which are on drying reef, are shown in the correct locations on the tablet file, but shown (the two west most ones) in relatively deep water.
ps. here is the webapp chart with the sonar detail turned out, as a direct comparison to the ipad display above.
Attachment 153528
I have sent a 'high priority' note explaining the issue to a contact I have at Navionics.
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Thanks for that, Evans. That chart, the i-pad version. is kinda incocmprehensible to me. Maybe due to lack of familiarity with the features of Navionics cartography, but seeing the reef markers depicted in deep water would be an alarm to me. At any rate, that does lend some credibility to the Navionics-aided reefings claim. Please let us know what their response is if you can.
But the basic nav error was still in attempting to skirt the reef too closely in the dark IMO.
Jim
__________________
Jim and Ann s/v Insatiable II, lying Port Cygnet Tasmania once again.
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06-08-2017, 14:11
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#255
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Senior Cruiser
Join Date: Aug 2009
Posts: 4,033
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Re: Leopard 46 lost in French Polynesia - stunning rescue pictures
Quote:
Originally Posted by Jim Cate
That chart, the i-pad version. is kinda incocmprehensible to me.
seeing the reef markers depicted in deep water would be an alarm to me.
the basic nav error was still in attempting to skirt the reef too closely in the dark IMO.
Jim
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Yes, I agree with all three points.
I have never seen an error like this before. It is not missing data, and it is not old/obsolete survey data, and it is not a data layer issue (the three typical errors). I don't really understand how the sounding got warped that way.
The stick markers are an obvious signal of something wrong, as is the simple lack of a fringing reef (which is a characteristic of these islands). However I'm not sure if those would have rung alert bells or not, if I was not specifically looking for errors.
This is an interesting mental test for people's nav and watch keeping practices . . . . Honestly envision yourself planning and executing this rounding . . . Thinking that chart was accurate . . . . How many of us would have managed to avoid the bad outcome? It could have been avoided in several ways, most obviously with more distance, a second charting source, and recognizing the depth sounding were not consistent with the chart (and I suspect the breakers on the reef would have shown up on radar) . . . . But how many people would honestly would have after a long day sailing? We actually always went around the north end of the island because the reef profile was 'safer' (this was back in the captain cook survey paper chart days) and it had better sailing angles.
In the past navionics have been pretty responsive making correction when very specific errors were detailed to them. But they have just "thanked me for my input", rather than actually acknowledged the error and correction, I suspect for legal reasons.
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