gilm
Seaman
Posts: 166
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Post by gilm on May 2, 2020 10:37:43 GMT -5
Gotta a 245 DC. Why do you think is reasonable safe setting for boat water depth and height setting for use in Garmin auto-guidance settings?
I was thinking 4' depth and 18' height (that includes antenna).
Any other suggestions, since I would like good setting and not over limit my route suggestions with big too conservative?
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Post by abouttime2fish on May 2, 2020 16:29:40 GMT -5
Where are you boating? Are bridges a known issue you should just plan lowering the antenna for? Pull those rods down too....
Here in NC there’s a lot of water under 5’, but that’s my alarm depth and when I start paying attention. Your height seems excessive, but does your Garmin account for tides?
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Post by fishnfool on May 2, 2020 18:57:51 GMT -5
4' seems plenty
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gilm
Seaman
Posts: 166
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Post by gilm on May 2, 2020 19:36:25 GMT -5
Where are you boating? Are bridges a known issue you should just plan lowering the antenna for? Pull those rods down too.... Here in NC there’s a lot of water under 5’, but that’s my alarm depth and when I start paying attention. Your height seems excessive, but does your Garmin account for tides? Good question about the garmin accounting for tide - hmmm - I gotta do little reading Sent from my iPhone using Tapatalk
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Post by fishnfool on May 2, 2020 20:16:38 GMT -5
I think like with their chart depths they show low tide so if you set to 4' thr plotter will plot it off the chart depths.
Navigating the sound in NC is unnerving. When I'm running on plane in 2' of water according to my sounder or my depth starts blinking because it is less that 2', I'm white knuckling it even though I know theres enough depth having been through the same spot many times, but it is thin, very thin.
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Post by abouttime2fish on May 2, 2020 20:30:50 GMT -5
I don’t like 2’ on plane, if you pull them back you’re stuck! But here in NC 5’ to 2-3’ usually takes plenty of time to react. I’ve not boated in the NE, but grew up there. I picture the depth change to happen much more rapidly. If it goes from 10’ to 2’ in a boat length, a 5’ warning probably won’t do you much good!
Also most of the NC sounds are sandy bottomed unless you are really pushing back ito the skinny stuff. Rocky bottom is a bit scarier!!
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Post by simon2360 on May 13, 2020 8:30:45 GMT -5
Gotta a 245 DC. Why do you think is reasonable safe setting for boat water depth and height setting for use in Garmin auto-guidance settings? I was thinking 4' depth and 18' height (that includes antenna). Any other suggestions, since I would like good setting and not over limit my route suggestions with big too conservative? I think it really depends on your area and what the cartography/contours looks like. For example: In South Florida we have some channels that are very narrow and go from 10ft to 1-2 within 50-75 feet wide. I would not use it as I like to be in tune with reading the depths and maps while navigating.
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Post by hookedup on May 13, 2020 12:08:26 GMT -5
I've read about the auto guidance on some other sites and even Garmin says:"Note: The Auto Guidance feature is based on electronic chart information. That data does not guarantee obstacle and bottom clearance. Carefully compare the course to all visual sightings and avoid any land, shallow water, or other obstacles that may be in your path."
One guy with AIS was on his way to an unknown site to him using auto guidance and got a call telling him there were high rocks where the auto guidance had taken him and he needed to change course immediately.
I don't have that feature and if I did, I'd have no fear using it in open water, but I'd sure be leery about using it in shallow waters. They are building second tunnels on the Chesapeake Bay Bridge tunnel and I'd bet that those rocks they dropped last week to extend the island aren't on the latest charts.
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Post by hookedup on May 14, 2020 11:28:11 GMT -5
Boattest just did a review of auto-routing systems from Garmin and Navionics. Seems like they don't really like them very much. Their summary:
Keep Checking. The display makes it quite clear that the proposed routes from auto-routing are not to be used for navigation without detailed checking -- but who reads the small print? It can be so easy to have a route plotted for you by auto-routing and then follow it implicitly just as you might do with your road system.
My advice is that auto-routing might be a guide to possibilities when you are at the planning stage of a cruise but when actually plotting the course stick to the tried and tested method of plotting it step by step and then checking it and checking it again.
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