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Navionics Ipad Users Beware

12K views 21 replies 12 participants last post by  colemj 
#1 ·
I recently participated in the delivery of a Beneteau First 44.7 from Phuket, Thailand to Jomtien, Thailand. The boat had a Raymarine chartplotter at the nav station but nothing at the helm. I mounted an IPAD 2 in a Nuud waterproof case on a ram mount on one of the stanchions beside the helm to use as a navigational aid while steering.

We used the chartplotter for primary navigation and the Ipad as a secondary navigation source. GPS position was provided by a Bad Elf GPS that we kept at the nav station.


This arrangement worked very well until the GPS ran out of battery power. This occurred during my watch at 3am. The Navionics app continued to show heading and speed and displayed the boat triangle indicating the position of the boat. It took me a long time to notice that the position was no longer valid and this put the boat at risk.

The navionics app should clearly show the user when it is no longer receiving GPS data. Now that I know this is a problem I can look for signs that the position is being updated, but it is a dangerous situation.
 
#4 ·
I recently participated in the delivery of a Beneteau First 44.7 from Phuket, Thailand to Jomtien, Thailand. The boat had a Raymarine chartplotter at the nav station but nothing at the helm. I mounted an IPAD 2 in a Nuud waterproof case on a ram mount on one of the stanchions beside the helm to use as a navigational aid while steering.

We used the chartplotter for primary navigation and the Ipad as a secondary navigation source. GPS position was provided by a Bad Elf GPS that we kept at the nav station.

This arrangement worked very well until the GPS ran out of battery power. This occurred during my watch at 3am. The Navionics app continued to show heading and speed and displayed the boat triangle indicating the position of the boat. It took me a long time to notice that the position was no longer valid and this put the boat at risk.

The navionics app should clearly show the user when it is no longer receiving GPS data. Now that I know this is a problem I can look for signs that the position is being updated, but it is a dangerous situation.
Every $50.- car GPS gives a warning when it has not longer GPS reception (like when you are going in a tunnel). As does my Android with the google maps app.

That a navigation app does not do that is amazing!
 
#9 ·
For what it's worth, I use iSailor on an iPad mini for a chart plotter connected via bluetooth to a Garmin Glo. It sets off a loud, annoying alarm when the GPS signal degrades or is lost. I keep a plot on paper chart as well and I use iSailor on my iPhone as well, to duplicate the whole process; obviously no one should ever rely on only one source of information. But this makes me feel better about the alarm.
 
#10 ·
That's not good. Some apps not only indicate the loss of GPS signal, but display the accuracy. 3-5 meters is as good as it gets. I've seen 100 meters, with the ipad down below. Even though I have a built in GPS receiver, I did buy a bluetooth external receiver as well. I sometimes use it when I want the anchor alarm running next to my bunk, but the signal strength down below isn't what I want. I put the bluetooth receiver outside, above my cabin. Admittedly, this hasn't proven necessary very often.

Even if you have a signal, it doesn't mean you are exactly where it claims. I've seen apps represent accuracy with a circle around the position. The bigger the circle, the less accurate, meaning you could be anywhere in that circle. Others display accuracy as a number. Note, not all these apps are marine, some are aviation. I simply know the ipad is capable of this feature.

All navigation should be double checked. ATNs and land features are the best. Even just confirming depth is better than taking the screen for granted, if nothing is in sight. Dead reckoning too.
 
#12 ·
Ajax, that is a good suggestion and I will look around. However, even with no alarm the app should not show speed and heading if it hasn't had a gps signal for 15 minutes.

Several respondents have questioned the use of an external GPS. The Bad Elf is WAAS capable so it is accurate to within 10 feet. I think this is more accurate than the internal GPS in an IPad. On my boat I will keep the Bad Elf connected to power at all times. On the delivery yacht we only had one usb port that was shared between 4 phones, the Ipad and the Bad Elf. The bad elf runs for 12-16 hours on a charge, so there was a tendency to forget about it.
 
#13 ·
No quarrel here with using an external GPS. I use a Dual GPS150 puck myself, with iSailor. The alarm is truly obnoxious.
I did attempt to query the Navionics site before posting here, but apparently they only put the user manual built into the software and not in downloadable .pdf format anywhere online.
 
#16 ·
Yes, we can do the same thing with several of our apps and programs. However, this still means that some part of the boat is at a minimum 10' off from the GPS's true position - be it bow, stern or side. Now add in a few more feet of inaccuracy.

At least with an internal GPS iPad, one could move it around the boat to the areas closer to danger :)

Mark
 
#22 ·
No, the cell connectivity has nothing to do with accuracy. The only advantage is in getting an initial fix, where triangulating off the cell towers will allow the first fix to be a bit faster. After the initial fix, there is no time difference in subsequent fixes unless you turn it off and move a great distance away. The difference on the initial fix time is measured in seconds, not minutes.

Mark
 
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