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Garmin Auto Guidance question

Old 02-12-2019, 04:15 AM
  #1  
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Default Garmin Auto Guidance question

We were boating in some new water yesterday (intra costal between Charlotte Harbor to Fort Meyers) and had the auto guidance set for a minimum depth of three feet which is about 18 to 24 inches higher than our boat drafts on plane. We were in a section of the intra costal where it got surprisingly tricky and the channel markers were so far apart that we couldn't see them (lesson learned we will now carry a set of binoculars on the boat).

The auto guidance more or less followed the channel, but veered off and I am sure that is because I had a minimum depth that was lower than the intra costal so the guidance was more of a direct route than following the main channel.

We are soon upgrading to a larger boat. So the question is in situations like this is there a default ( I couldn't find one) to have the auto pilot/Garmin follow a mapped channel such as an intra costal waterway or is the way to do it set a min depth high enough that the plotted route will stick to the channel which should be the deepest water?
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Old 02-15-2019, 06:58 AM
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Seems crazy to me, but auto guidance calculates a route based on charted depth only, without regard to marked channels. Personally I think it's a poor design, especially given the routine effects of shoaling, shifting, etc on charted soundings. I refuse to use it, but my plotter is a couple of generations old; maybe the new(er) units have a way to default to marked channels.
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Old 02-16-2019, 02:24 AM
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Originally Posted by willw View Post
We were boating in some new water yesterday (intra costal between Charlotte Harbor to Fort Meyers) and had the auto guidance set for a minimum depth of three feet which is about 18 to 24 inches higher than our boat drafts on plane. We were in a section of the intra costal where it got surprisingly tricky and the channel markers were so far apart that we couldn't see them (lesson learned we will now carry a set of binoculars on the boat).

The auto guidance more or less followed the channel, but veered off and I am sure that is because I had a minimum depth that was lower than the intra costal so the guidance was more of a direct route than following the main channel.

We are soon upgrading to a larger boat. So the question is in situations like this is there a default ( I couldn't find one) to have the auto pilot/Garmin follow a mapped channel such as an intra costal waterway or is the way to do it set a min depth high enough that the plotted route will stick to the channel which should be the deepest water?
To me the idea that you would use Auto guidance in unknown waters, or for that matter in a channel, is shocking. And you don't carry binoculars to assist you in navigation? My suggestion is learn how to be a responsible boater before you buy a bigger boat. If that doesn't work for you sell the boat and take up golf.
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Old 02-16-2019, 04:41 AM
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Originally Posted by willw View Post
We were boating in some new water yesterday (intra costal between Charlotte Harbor to Fort Meyers) and had the auto guidance set for a minimum depth of three feet which is about 18 to 24 inches higher than our boat drafts on plane. We were in a section of the intra costal where it got surprisingly tricky and the channel markers were so far apart that we couldn't see them (lesson learned we will now carry a set of binoculars on the boat).

The auto guidance more or less followed the channel, but veered off and I am sure that is because I had a minimum depth that was lower than the intra costal so the guidance was more of a direct route than following the main channel.

We are soon upgrading to a larger boat. So the question is in situations like this is there a default ( I couldn't find one) to have the auto pilot/Garmin follow a mapped channel such as an intra costal waterway or is the way to do it set a min depth high enough that the plotted route will stick to the channel which should be the deepest water?
Iím familiar with those waters and my buddy has a boat equipped with Garmin that we tried to use the autoguidance feature in those channels with poor results. I always wondered if other chart plotters worked better or this was just too much to ask? With the updated mapping to Garmin this year Iím going to try it again after the G3 vision card is available and see if it works better. Iím sure plenty of boaters wondered the same thing.

Ansel youíre a complete jerk,
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Old 02-16-2019, 04:45 AM
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You beat me to the punch😀

To our good friend good friend Captain Ansel have a great day!
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Old 02-16-2019, 03:06 PM
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Let alone running up on plane in unknown waters jeez, was the common sense left in the truck seat at the boat ramp. Who In there right mind would even have the boat on auto pilot in restricted waters that they had some machine auto route there route. You must own a Tesla also don't you?
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Old 02-16-2019, 04:10 PM
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when you make the auto route, it asks you to check it. so when you check it (being a responsable boater) you would have noticed that it was incorrect. at which point you can move any of the points to the correct place. and fix the route. before you accept it

it sounds like you accepted it's "recommendation" .. without even looking at it or checking it.

I would never use auto routing in tight waters. even using a pilot is questionable. especially considering I've read many posts on here of garmin maping being off by 200+' in some channels.
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Old 02-16-2019, 06:24 PM
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I’m not a big auto Guidance fan as the depth settings for the boat seem to drive the route. If I do use it I select a saved track that I made for the routing.

No no way would I use auto route in unfamiliar waters.
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Old 02-16-2019, 08:19 PM
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Auto Guidance is exactly that. A guide. You cant trust it 100%. Even GPS error will cause issues. I use the GPS19x due to less error than the built in source but I still notice a difference in my actual position vs the map in tight quarters. If I am running an area frequently, I create my own route by running my course and saving the track to help stay closer to where I actually want to run, however even this is not always fool proof. I run a marked channel with several curves. Even with my own route, the autopilot will sometimes cut it too close to the buoys for comfort when turning and this is using a route created by running down the middle of the channel the entire way. Nowadays I mostly just pick a route, hit auto guidance and use it as more of a reference, and either manually steer or just use a heading hold and steer as needed until I get to open water. As always, stay at the helm and keep very a close watch on your surroundings.
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