What is your backup GPS solution?

capta

.
Jun 4, 2009
4,766
Pearson 530 Admiralty Bay, Bequia SVG
I am under the impression that if you pay for Navionics or other electronic charts that have a business model of issuing paid updates, then you're getting the same accuracy and updates the commercial boats get.
Not for areas not commonly used by commercial shipping. The updates are most likely from the charting organizations like NOAA using info from the CG & USACE, not from the companies like Navionics. They only make them available in a format you, as their customer, can use.
 
Oct 24, 2010
2,405
Hunter 30 Everett, WA
Alot of people are listing IPADs. I was excited when u got my IPAD gen 6 from work to use then I found out they don't have GPS! You have to have a cell version. You guys with the IPADs all have cell on them?
We do. Too bad it's so expensive.
Ken
 
Oct 22, 2014
20,989
CAL 35 Cruiser #21 moored EVERETT WA
You guys with the IPADs all have cell on them?
No. But you need to have a GPS receiver to make the chart plotter give you your position. So I get the GPS signal from my AIS system. The AIS system links the iPad via wi-fi. Then I have an app that can use the wi-fi information (iNavX) and display the nema2000 data on the iPad charts.
It is great when everything works. So far no glitches or gremlins
 

dLj

.
Mar 23, 2017
3,370
Belliure 41 Sailing back to the Chesapeake
I've hesitated to add anything to this thread as the stated question is what is my back-up system for GPS. In fact the question does not apply to me. GPS is my back-up system for my eyes, ears and charts when running in cosatal navigation and GPS is the back- up system to my sextant when running in off shore out of sight of land legs.

In that way I keep my navigation skills honed and always front and center in my navigation tool chest. It is not that I am at all skeptical of the capability of GPS. It is a fantastic technology and highly reliable. But rather my choice is based upon my philosophy of sailing. I feel that sailing has become grossly over "technologisized" (if I can invent a term).

I strongly feel that one should learn to sail through direct observation and utilize ones brain rather than such a heavy dependence on technology. I don't need to keep my eyes on an electronic representation of my point in space. I need to keep my skills honed to know this through dead reckoning and keeping good llogs.There is also, in most cases - there are exceptions, no need to be so tuned into knowing exactly where you are at any given point.

I recall an ocean traverse I did a number of years ago prior to GPS, back when satnav was functioning. We could get a fix from satnav about once every four hours. We thought it was amazing as prior to that we ran exclusively by sextant and we may get a fix once a day, at best. At times it would be less often depending upon weather.

And that was way more than enough for an off-shore run. Now with GPS you know where you are every second. You can track you movements to such a high degree, and outside of difficult entrances, why do you need this? Learn to feel and see the sea. OK so if you are running some of the channels in the Georgian bay, for example, GPS is a godsend. But outside of the specific, and relatively few examples on the world scale, I really reject this dependence on GPS.

Run your coastal cruising with compass, chart, and dead reckoning, and then check your self with a back up GPS. That will teach you much more than the other way around.

Racing is a different story. If you want to be competitive racing you need to use GPS, and lots more....

dj
 
Nov 1, 2017
635
Catalina 25 Sea Star Base Galveston, TX
regarding Backup of a fixed GPS
Ah, I see. Well, on my boat I don't have one, but a friend of mine owns a J34 that has a Garmin and a Raymarine. Don't know the model numbers, but one is at the nav station in the cabin and the Garmin is in the cockpit.
 
Jun 14, 2010
2,081
Robertson & Caine 2017 Leopard 40 CT
Not for areas not commonly used by commercial shipping. The updates are most likely from the charting organizations like NOAA using info from the CG & USACE, not from the companies like Navionics. They only make them available in a format you, as their customer, can use.
I read your post a few times and not sure it's clear to me. As a user I know that Navionics does update the charts regularly with government notices but they also use crowd-sourced data from people who share their depth readings. You can download the updates as often as you want (with a subscription). They call the crowd-sourced soundings data SonarChart and it's available as an overlay in the Navionics app. I have found SonarChart to be more accurate than government or even Navionics own standard depth overlay charts, and consistently so. Even in places "not commonly used by commercial shipping".
 

capta

.
Jun 4, 2009
4,766
Pearson 530 Admiralty Bay, Bequia SVG
I read your post a few times and not sure it's clear to me. As a user I know that Navionics does update the charts regularly with government notices but they also use crowd-sourced data from people who share their depth readings. You can download the updates as often as you want (with a subscription). They call the crowd-sourced soundings data SonarChart and it's available as an overlay in the Navionics app. I have found SonarChart to be more accurate than government or even Navionics own standard depth overlay charts, and consistently so. Even in places "not commonly used by commercial shipping".
As I've never before heard of that, I suppose my posted information is as much a dinosaur as I am. I stand corrected.
 
Sep 25, 2018
258
Catalina Capri 22 Capri EXPO 14.2 1282 Stony Point
Have used my eyes, paper charts and a hand held Garmin 76c. My iphone is a back-up that I have never had to use. The Garmin is made of iron! Its been bounced about the cockpit for about 12 years and always starts right up and confirms what my eyes see. My new boat has a Garmin echomap 50s chart plotter/fish finder. Bought a Garmin 78cs as a stand-by along with my phone. Moving the 76c to Florida for my little day sailer so I don't have to transport it back and forth. The Garmin hand held has performed great allowing my to mark out shallows on Florida to keep my swing keel down and not scratching bottom. The phone is my back-up that has never been used.
 

TomY

Alden Forum Moderator
Jun 22, 2004
2,758
Alden 38' Challenger yawl Rockport Harbor
Charging (or lack of charging), is a big plus with tablets and phones now running nav. software. And there are other charge sources available today. I use several Makita 18VDC tools that use Li-ion batteries. I have an adaptor that converts the batteries to USB chargers.

Two USB ports, batteries in various Amps, these chargers (and many other Li-ion battery USB chargers), give another back up source of charging if you lose your ship charging source(s).

They could even serve as additional USB plugs instead of installing a circuit. I suspect a 4, 5 or more amp battery would charge-run devices for many hours.

 
Jun 14, 2010
2,081
Robertson & Caine 2017 Leopard 40 CT

TomY

Alden Forum Moderator
Jun 22, 2004
2,758
Alden 38' Challenger yawl Rockport Harbor
Tom, I use a backup battery that’s about the same size as my iPhone 8, but it has enough power to recharge my iPhone at least 3 times, or an iPad once. Its compact form factor means it's pocketable and packs well for travel, when it’s more likely I’ll need extended runtime. I’ve had it more than 2 years and it’s holding up well.
https://www.amazon.com/gp/product/B06XRVHDLM/ref=oh_aui_search_detailpage?ie=UTF8&psc=1
Those look great, Larry. I was thinking these larger batteries have higher storage for longer term use.

We spent a month onboard this past season and had plenty of power to keep stuff charged and running. But a couple of these 6AH - 18VDC batteries fully charged on hand might be handy as extra USB ports as well as for charging,...if you have them on hand anyway. :)

Cell Capacity: ZMI 10,000 mAh × 3.85V = 38.5 watt hours vs Makita 6 AH battery 18 x 6.0 = 108 watt hours
 

capta

.
Jun 4, 2009
4,766
Pearson 530 Admiralty Bay, Bequia SVG
approaching a strange port at night I use this method- heave too offshore til daylight No matter what electroniccs I may have Yep- I'm a chicken
Doesn't it really depend on the port? A well lit entrance like NYC, Charleston, or Ft Lauderdale are a breeze to enter anytime, whereas the big open bay at FdF Martinique can be a nightmare with the myriad of lit and unlit marks set in front of the town as a background, though it is still pretty easy if one has a GPS chart plotter and an up to date Doyle's cruising guide.
However, one place we know well that I hesitate to enter in the dark (though I will leave in the dark) is Chaguaramas, Trinidad. There are so many unlit vessels at anchor, so many moorings and just plain garbage in the water that we'll go in as far as Scotland Bay and wait there for daylight. Of course, as immediate check-in is required 24/7 there, it doesn't make sense to arrive before "office hours" as the overtime penalty is pretty expensive.
 
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Gunni

.
Mar 16, 2010
5,937
Beneteau 411 Oceanis Annapolis
This is one of those things where Conventional Wisdom, an obscure British seaman from the age of hemp and obscure atolls, I believe said, “heave-to and wait for dawn’, and it gets repeated like liturgy.

These days in the modern world commercial traffic and the dreaded fishing boats are plying lanes near and far to port shipping lanes at all hours. They’re really not very good at picking out a little sailboat in the mist on a dark night. They move fast and don’t divert. So you fall in line and run with the traffic and get to port. If you don’t have the tools or the skill you sail past a strange port, and find a new destination for daylight arrival.
 
Jun 14, 2010
2,081
Robertson & Caine 2017 Leopard 40 CT
Those look great, Larry. I was thinking these larger batteries have higher storage for longer term use.

We spent a month onboard this past season and had plenty of power to keep stuff charged and running. But a couple of these 6AH - 18VDC batteries fully charged on hand might be handy as extra USB ports as well as for charging,...if you have them on hand anyway. :)

Cell Capacity: ZMI 10,000 mAh × 3.85V = 38.5 watt hours vs Makita 6 AH battery 18 x 6.0 = 108 watt hours
Yes, no doubt those Makita batteries pack more juice. Not only that - if it’s already part of your toolkit it’s a fantastic solution to use your setup, and it makes sense to zero in on one “standard” battery type.
 
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