Auto Guidance Garmin

[busybee]

I have a Garmin 451s with the Blue Vision card in place,
When I choose a safe waypoint and then auto guidance I get the error message
unable to plot route unless I am about a mile away from any obstacle at start or finishing waypoint.
I have set my boat to min depth 1.5m, shoreline near and min high of 2.5m.
The route to guidance works fine but would direct through land unless you manually input a saved route.
So is auto guidance useless or am i missing something?

[gpsguru]

Auto guidance from most Garmin plotters (I use a 95SV) only is available when you use the Blue Chart G2 Vision HD charts ................ this is certainly the case with the later plotters that use auto Guidance V3 technology .......... yours is quite an old plotter now, but I seem to remember that you would need an upgrade chart.

I always smack in a few waypoints and use 'navigate to' for each waypoint.

I am the one who is responsible for shallow water and hazard avoidance .......... I wouldnt want to leave those decisions to a plotter !

[busybee]

Yes it is a Garmin Blue Chart G2 Vision card, 5 years old now though

[gpsguru]

Originally Posted by busybee

Yes it is a Garmin Blue Chart G2 Vision card, 5 years old now though

I think it needs to be the Blue Chart G2 Vision 'HD' (high Definition)version, which is quite expensive (£200+ last time I looked)

[Xk59D]

i have a pair of garmin plotters with g2 HD on them, mines will also happily take you over land. I've never bothered messing with it but I assume it is user error, it has to be better than that.

my boat is away for new seats being fitted but i'll have another look when it comes back.

[gpsguru]

Originally Posted by Xk59D

i have a pair of garmin plotters with g2 HD on them, mines will also happily take you over land. I've never bothered messing with it but I assume it is user error, it has to be better than that.

my boat is away for new seats being fitted but i'll have another look when it comes back.

Probably not user error, as you have to enter a fair few parameters to set it up correctly ...... even tehn, it will come up with a numer of warnings and disclaimers ........... however, I think any coastal passage should be the skippers responsibilty and not entrusted to a plotter !

Having said that ............ I still think that Garmin plotters and sonar are one of the easiest and most intuitive to use ............

[Xk59D]

Why shouldn't you trust the plotter? It is how most of us navigate and knowledge/compass as a backup. I don't even have paper charts rightly or wrongly!

If I'm using it correctly the garmin auto navigation sucks, I've barely even tried it as I manually enter points but that is still trusting the plotter.

[beamishken]

We have garmin plotters in our hard boat and the rib. It depends on whether you select route to or guide to,
Route to will draw a straight line to the destination you then pull the route to your chosen turn points
I usually use guide to which plots the course and puts in the turns it works fine but always seems a bit close to shore for comfort and I usually run outside of the course .To be fair though the course is always through safe water

[willk]

Originally Posted by Xk59D

Why shouldn't you trust the plotter?

Well, it doesn't have any skin in the game
You shouldn't trust them because they haven't a baldy about the water you're about to transit. They know how deep it is - that's it. They don't know/care about tidal races, high traffic areas, MOD exclusion zones, contours that are heavily potted and a host of other things you do/should know.

Used carefully and thoughtfully, I can see how it might work well. I have it but have never felt the need.

[Xk59D]

i can only speak about garmin as that is all i have had exposure to recently but tidal info, MOD exclusions are on there or atleast as upto date as the last card update anyway.

you said it knows depth...so you trust it for something.

ofcourse preparation for the voyage is still a very worthwhile exercise as it isn't unknown for plotters to fail or lose GPS, but whilst underway i would trust it if the compass is pointing where i'm expecting it.

in my case it would be nice if it worked to maybe help mrs get home/safety in case something happens so i'll have a look at it again. TBH that is pretty much only reason i wanted to make use of the auto feature.

[gpsguru]

Originally Posted by Xk59D

in my case it would be nice if it worked to maybe help mrs get home/safety in case something happens so i'll have a look at it again. TBH that is pretty much only reason i wanted to make use of the auto feature.

OK ......... I now see where you are coming from ..............

My wife knows that if anything renders me incapable, then she drops the pin and calls a distress on the radio ........... if we are outside of radio range (unlikely) then she activates our PLB ...........however, if she considers my problem not to need immediate attention, then she knows how to follow the 'active track' back to where we started .......... following the active track is probably safer than plotting a new course, especially if visability is bad.

At least a couple of times a year we also practise MOB by lobbing an A3 buoy overboard .......... she knows to hit MOB on the plotter, she knows to keep one eye on the MOB and not lose contact, and she knows to do a williamson turn ........ she knows how to bring the RIB alongside the MOB and deploy a throwing rope ............

[Poly]

Originally Posted by beamishken

I usually use guide to which plots the course and puts in the turns it works fine but always seems a bit close to shore for comfort and I usually run outside of the course .To be fair though the course is always through safe water

I've only used it once (as an experiment), (for 100NM ish - so certainly not the issue the OP described). The experience was similar - it plotted a safe route - but it wanted to go much closer to the shore than I would have done either navigating "by eye" or if plotting waypoints. If you really want to test your nerve you need to add an autopilot into the mix!

Originally Posted by willk

You shouldn't trust them because they haven't a baldy about the water you're about to transit. They know how deep it is - that's it. They don't know/care about tidal races, high traffic areas, MOD exclusion zones, contours that are heavily potted and a host of other things you do/should know.

That is interesting - I'd have thought that by now they should be aware of other charted hazards like exclusion zones and TSS, perhaps even building in tidal offset for WAFIs; and if my car can tell me where the speed cameras are then it should know areas with "pot problems". However, regardless of how good it is 99.9% of the time, it is bound to screw up sometimes, just as road sat nav sends people really bad routes.

Originally Posted by Xk59D

you said it knows depth...so you trust it for something.

if an HGV driver hits a low bridge because his sat nav took him that way who is to blame? That is Willks point. Just because it knows where the "road" is doesn't mean there aren't other hazards a competent skipper should avoid.

in my case it would be nice if it worked to maybe help mrs get home/safety in case something happens so i'll have a look at it again. TBH that is pretty much only reason i wanted to make use of the auto feature.

In my very limited experience it wasn't trivial to set up and use. The thought of "allowing" an inexperienced helm/navigator to use and trust the result in what are presumably stressful circumstances would fill me with concern. I'd much rather Mrs P had a rough inkling how to navigate "properly" than blindly follow the instructions.

[busybee]

My point was that it would only plot an auto guidance route if at least a mile away
from any danger, not that I want to rely on its instruction, in the same way that I use a road sat nav.
You would not go the wrong way past a no entry sign or into a field just because your sat nav was telling you to!
It seems to me for £100 a road sat nav for the whole of Europe does a better
job compared to mine.

[beamishken]

There must be something wrong in the settings on your plotter. I use the autoguidance all the time and it takes me closer to hazards than I'm comfortable with.
I was in Douglas Iom last week and it plotted me a course from the inner harbour to Largs without a problem
It didn't tell me to wait until the tidal flap was down or the bridge was up before leaving the inner harbour.
Occasionally it will have a wobbly and say unable to calculate autoguidance for no apparent reason it just doesn't seem to like certain places. It's not happy if I put the destination too close to where I'm heading so I usually set the destination half a mile or a mile from where I'm going.
Do you have the problem from the same home port or is it the same wherever you are?

[busybee]

the message unable to calculate route occurs in East and central Solent areas unless I am right out in the middle of the Solent then it might work, no chance
in Chichester or Langstone harbour, my settings are for Shoreline near but no distance is given on that setting.It would give autoguidance from say Cowes entrance to Bar beacon Chichester.

[beamishken]

It's possibly related to depth settings mine will only occasionally refuse to plot a route and usually you can see an obstruction it wouldn't like.
Why not set all the depth alarms etc to zero and see if it changes

[busybee]

I have set the depth setting to the min allowed which on the Garmin is 3ft, maybe
it assumes route at LAT, but even that would not explain some areas unable to plot route messages.
I am going to try try download a clean new copy of the maps to another SD card

[beamishken]

To be honest I don't think I've altered depth alarms on either of my units could you return to factory defaults? Or maybe turn off the depth alarm as an experiment. We are on the Scottish West coast which tends to be a fair bit deeper than the solent
It's maybe not liking the marginal depths that you have around your local area

[Dru]

Hi
I seem to be the exception here I have a 7012 12" plotter with the blue vision g2 chart and it works really well.

That said if you press navigate to it draws a straight line to the destination however if you press guide to it draws a spot on course with way points

I really like it

[breezeblock]

Originally Posted by Xk59D

i can only speak about garmin as that is all i have had exposure to recently but tidal info, MOD exclusions are on there or atleast as upto date as the last card update anyway.

you said it knows depth...so you trust it for something.

ofcourse preparation for the voyage is still a very worthwhile exercise as it isn't unknown for plotters to fail or lose GPS, but whilst underway i would trust it if the compass is pointing where i'm expecting it.

in my case it would be nice if it worked to maybe help mrs get home/safety in case something happens so i'll have a look at it again. TBH that is pretty much only reason i wanted to make use of the auto feature.

the auto feature is handy when your really drunk just follow the line to get yourself back from the pub hey presto