Has anyone else noticed that the tidal information on the Navionic Compact Flash card that is used in Raymarine chart plotters is exactly opposite of real life conditions. I first noticed this when I was bringing my new C350 home for the first time. The entrance channel where I keep my boat is relatively shallow so I make it my practice to be aware of the tide heights. I have been using Tides & Currents software for many years and have been amazed at how accurate it is. As I was approaching the entrance to my home port I checked what my new C80 had to say about tide height. Since I had planned my arrival for high slack, I was quite surprised to see that the predicion from the Navionics software predicted low slack. I checked all the obvious reasons for this before I called Navionics. I was quite surprised at their attitude. They informed me that there is a warning note that basically releases them from liabilty by stating that multiple navigational information should be consulted. Since that time I have checked out different chart plotters at West Marine using the same software and found that in every instance it was directly opposite what the actual tide height was in reality. To put it another way, Hide tide is always predicted when low tide is occuring and vice versa. If you are using Navionics software on your boat be aware that it cannot be trusted. Of course the prudent mariner should not depend entirely on their chart plotter but I know many that do.
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Rick I
Navionics No!!
Navionics is not the most responsive company. Their Bahamas chip is very poor and when I raised this with them they told me they had a "new" version but could not or would not tell me whether the geo referencing errors I noted were corrected. I really didn't want to buy another chip and find out it had the same errors. On the question of tidal data I have found it to be accurate. The data they use is the same as that used by everybody. Have you got the correct date and time on your plotter? Quite often the time is set wrong on the plotter resulting in wrong tidal information. Check your date and time. Rick I B393 http://groups.yahoo.com/group/beneteau393/ 393 group
Navionics is not the most responsive company. Their Bahamas chip is very poor and when I raised this with them they told me they had a "new" version but could not or would not tell me whether the geo referencing errors I noted were corrected. I really didn't want to buy another chip and find out it had the same errors. On the question of tidal data I have found it to be accurate. The data they use is the same as that used by everybody. Have you got the correct date and time on your plotter? Quite often the time is set wrong on the plotter resulting in wrong tidal information. Check your date and time. Rick I B393 http://groups.yahoo.com/group/beneteau393/ 393 group
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Bob V
Time Check
Thanks for the tip Rick but that's not it. I just checked again and the time setting is correct. I think it knows the time from gps data. The predictions for 10/22/06:0602@0.0,1316@8.2,1800@5.4 & 2328@8.5. Tides & Current Pro predicts :0612@8.2,1128@5.0,1631@8.4 & 1144@-0.7. T & C Pro matches actual tide height very closely. Perhaps the different results we are noticing are due to the large distance between the areas that you and I are navigating around. I am in the Pacific Northwest. I have found the position accuracy to be very good in the areas that I cruise and I always use manual navigation techniques as backup.
Thanks for the tip Rick but that's not it. I just checked again and the time setting is correct. I think it knows the time from gps data. The predictions for 10/22/06:0602@0.0,1316@8.2,1800@5.4 & 2328@8.5. Tides & Current Pro predicts :0612@8.2,1128@5.0,1631@8.4 & 1144@-0.7. T & C Pro matches actual tide height very closely. Perhaps the different results we are noticing are due to the large distance between the areas that you and I are navigating around. I am in the Pacific Northwest. I have found the position accuracy to be very good in the areas that I cruise and I always use manual navigation techniques as backup.
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Rick I
Local time
Bob, Yes you do get the time from the gps but you have to set the LOCAL time offset to correctly use the tidal data. Rick B393 http://groups.yahoo.com/group/beneteau393/ 393 group
Bob, Yes you do get the time from the gps but you have to set the LOCAL time offset to correctly use the tidal data. Rick B393 http://groups.yahoo.com/group/beneteau393/ 393 group
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Bob V
Not time related
On my previous post I included the data from Navionics and the data for Nobeltech for comparison. At no time of the day does the Navionics predict what is actually happening. Also my chart plotter does show the actual local time correctly. I am happy with the performance of the software in terms of displaying my position but it is never correct regarding tide heights. You mentioned cruising in the Bahamas. There is probably not much difference in tide height from low to high in that area but up here in the PNW we can have a 12 foot range on a spring tide.
On my previous post I included the data from Navionics and the data for Nobeltech for comparison. At no time of the day does the Navionics predict what is actually happening. Also my chart plotter does show the actual local time correctly. I am happy with the performance of the software in terms of displaying my position but it is never correct regarding tide heights. You mentioned cruising in the Bahamas. There is probably not much difference in tide height from low to high in that area but up here in the PNW we can have a 12 foot range on a spring tide.
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Rick I
Time related?
Bob, It appears that your Navionics is about 6 or 7 hour out on the tide if it shows high when the tide is low and vice versa. This would be about the same as your offset from GMT in PNW. Notwithstanding you assertion that the error is not related to time I would investigate this aspect again. As for tidal range this has nothing to do with whether the information is correctly presented, whether it's 12 feet or 4 feet is irrelevant. I am familiar with the Raymarine plotter, especially the C series. Once it is set correctly it does a good job on tides.
Bob, It appears that your Navionics is about 6 or 7 hour out on the tide if it shows high when the tide is low and vice versa. This would be about the same as your offset from GMT in PNW. Notwithstanding you assertion that the error is not related to time I would investigate this aspect again. As for tidal range this has nothing to do with whether the information is correctly presented, whether it's 12 feet or 4 feet is irrelevant. I am familiar with the Raymarine plotter, especially the C series. Once it is set correctly it does a good job on tides.
my C80 with the navionics works just fine
Somethings is set up wrong (or broken). My C80 with Navionics charts works just fine. Cat
Somethings is set up wrong (or broken). My C80 with Navionics charts works just fine. Cat
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