Garmin keel offset question

I have a Garmin plotter and a Raymarine transducer (didn't want to change transducers when I upgraded plotters). I can't get the keel offset function to save my keel size. Is that because I don't have a Garmin transducer, or am I just doing it wrong?

I sent an email to Garmin support but thought someone here might know the answer.

If you have networked chartplotters you will need to set the offset on each plotter.

Assuming you can see the depth meaning the transducer is working....
From the home screen select configure>my boat>keel offset
Select the number you want to configure (should be an on screen selection maybe using the rocker switch)
Select done
It will differ slightly depending on model of plotter and if you have a digital network box.

I only have the one plotter.

I can input the keel size but the plotter will not save it for some reason.

I doubt it's the transducer if it's working otherwise. You may be doing something wrong.


As with any computer, try turning it off and back on again. Maybe it will work then.

This is all the manual says. I don't have the "intelliducer" so that's why I thought my old Raymarine transducer might be the problem.

I have attached the instruction for my Garmin as it may help.

Let me guess, you can see the offset you put in reflected in the digital depth display on the sounder but the picture on the sounder showing the bottom and depth to the bottom does not reflect the offset you put in?

...

I went through the same thing with our new Garmin units. Tried multiple times to get the graphic display to refect the offset. Even had the installers try it. Gave up and called Garmin. And guess what, according to them, the offset will only be reflected in the digital read out. Never on the bottom picture! I said you have got to be kidding me! Why the hell would I want to have two depth readings on one display? Or at the very least not be able to fully control what I see on the screen they way I want it?

And since no offset can be put into the display that means you can never get it to read true depth or depth under the keel, correct? "Correct" they said. So I said in that case you have to know how deep the transducer is mounted under the water and take that into account to understand what the depth displayed on edge of the picture is telling you. "Correct" again they said.

Total BS I think.

And I don't recall ever having a bottom machine that when you put an offset in it didn't show up on both the digital and graphic display. And I told Garmin that.

The person on the phone did not disagree that this made no sense and claimed he would pass my thoughts on it up the line.

I suggest you call them, and if you agree with me that this is BS, tell them so. Perhaps if enough people point out how foolish this is, in a future software up date they can correct it. Or at the very least in new models people will not face this issue.

obthomas said:

I have attached the instruction for my Garmin as it may help.

Click to expand...

That's what I'm doing, but the depth shown on the plotter screen doesn't change.

My screen looks like this with the depth on the bottom left.


Is this what you are talking about Capt Bill? If so, where is the keel offset depth shown?

cardude01 said:

That's what I'm doing, but the depth shown on the plotter screen doesn't change.

My screen looks like this with the depth on the bottom left.
View attachment 47785

Is this what you are talking about Capt Bill? If so, where is the keel offset depth shown?

Click to expand...

No. I'm talking about the fact that when your display is set to show a graphic picture of the depth, the digital depth display will reflect the offset you put in. But the depth graph on the edge of the picture showing the depth to the bottom will no reflect the offset. Only the digital depth display will show the depth with an offset.

What you seem to be asking is why the depth numbers displayed on the charts don't change when you put in an offset.

If that is what you are asking, the numbers on the chart will never change. And they are not supposed to,

The digital depth in the lower should reflect the offset.

The digital readout is showing the depth under the keel. The graphic display is showing water depth from the surface to the bottom. The fish icons are then correctly shown at their actual depth below the surface. Two different pieces of information.

I'm trying to get the digital display on the bottom left to display the keel offset-- depth from bottom of the keel to the bottom of the bay. That's the number that I can't get to change. When I enter the keel size in the offset screen it doesn't save what I put in after I hit "done".

I will have to get in front of the plotter and try again. I must be doing something wrong.

hmason said:

The digital readout is showing the depth under the keel. The graphic display is showing water depth from the surface to the bottom. The fish icons are then correctly shown at their actual depth below the surface. Two different pieces of information.

Click to expand...

No. The graphic display does not show true depth from the surface because you can not put an offset in.

The unit is not smart enough to know how many feet the transducer was mounted under the way on the hull of the vessel.

Finally figured this out. The keel offset has to be set from the Raymarine ST60 depth gauge (that's down below and that I never look at) which evidently feeds my Garmin with depth info.



Now I need to figure out how big my keel is...

According to some ads on Yachtworld you draft is 3" 8"..........

cardude01 said:

Finally figured this out. The keel offset has to be set from the Raymarine ST60 depth gauge (that's down below and that I never look at) which evidently feeds my Garmin with depth info.



Now I need to figure out how big my keel is...

Click to expand...

The easiest way to do this is to measure the true depth of the water under the area of the boat near where your transducer is mounted, then subtract 4' + from the true depth number (if your draft is 3'8") and depending on how much safety margin you want. Then set your depth finder to read that resulting number and you'll have the depth under your keel with or without a bit extra if you choose.

I have the offset set so that when the readout says 3.5 I know I am in trouble since my boat has a 3.5 foot clearance.
I certainly have gone thru the mud before. One time at a low tide I actually grounded out, odd sensation the boat no longer moving up and down. Had to wait an hour to get moving again.

Would you rather have the offset set so that when it read zero, your in trouble?, or go with you hull depth? I tend to like the idea of knowing that when it says 3.5 feet, if I measure from surface to bottom, i will get 3.5 feet.

I didn't bother to set my keel offset on the depth sounder. My draft is 3' and my sounder is about 1.5' below the waterline. So If I see 3' on the sounder I worry, but I still have about 1.5' of clearance. I don't go anyplace where the sounder shows less than 3', just for safety sake.

TDunn said:

I didn't bother to set my keel offset on the depth sounder. My draft is 3' and my sounder is about 1.5' below the waterline. So If I see 3' on the sounder I worry, but I still have about 1.5' of clearance. I don't go anyplace where the sounder shows less than 3', just for safety sake.

Click to expand...

Hmmm. That's a really good point.
It's kind of weird having the depth go down so low after adjusting for the keel size and basically hitting bottom when it says zero.

Capt.Bill11 said:

The easiest way to do this is to measure the true depth of the water under the area of the boat near where your transducer is mounted, then subtract 4' + from the true depth number (if your draft is 3'8") and depending on how much safety margin you want. Then set your depth finder to read that resulting number and you'll have the depth under your keel with or without a bit extra if you choose.

Click to expand...

Ahhh, this makes sense. Thank you

cardude01 said:

Hmmm. That's a really good point.
It's kind of weird having the depth go down so low after adjusting for the keel size and basically hitting bottom when it says zero.

Click to expand...

Everybody sets it up they way they like. But for me hitting bottom at or about at zero makes sense to me. As in at zero I have zero clearance under the lowest point on the boat.

Which in the case of the boat I run now is the props not a keel. On many boats there is no significant keel hanging fown to protect the props and/or rudders.