[DG11] Sonarchart Live, depth offset

[Derek - Raymarine - Moderator]

Hi moki38

The internal sonar using the Sonar transducer is entirely independant of the transducer used with the depth instrument.

The settings used for the depth transducer are not used by the sonar

The depth measured by the Depth transducer, shared by the AXIOM in the STng databox is a repeated display only and does not have any influence on the sonar depth measured directly by the AXIOM.

The AXIOM can therefore display two different depths, one a repeat from the data from STng and the other derived from its own Sonar transducer.

The Sonar transducer can have an offset entered, but this does not get used when using SONARCHART live for the reasons advised before.

Thanks

[moki38]

Thanks once again Derek, for your time and effort.

But once again, you managed to get me confused again.

So, lets see if i get this right:
- The Sonar transducer, is independant of the Depth transducer.

Yes, this is what i would expect.

- The settings used for the depth transducer are not used by the sonar.

Sorry, i would say No to this part. If i keep the Sonar transducer offset to "Below Waterline", but change the Depth transducer offset to "Keel". The Depth displayed on the Sonar changes and SonarChart Live doesn't show the depth calculated with the Sonar offset. But the depth calculated with the Depth Transducer Offset.

- The Sonar transducer can have an offset entered, but this does not get used when using SONARCHART live for the reasons advised before.

I understand why i would need to set the Sonar offset to "below waterline", as that would be the only way to calculate the true depth, without an extra offset. I fail the see, why it doesn't use the offset in SonarChart Live.

[Derek - Raymarine - Moderator]

Hi moki38

I am sorry that this is not clear.

The offset used by the depth Tx is local to the Depth display and is set within the Depth instrument.

The offset used by the Sonar is local to the Sonar and is set by the sonar app in the MFD

The Sonarchart Live simply does not use any keel offset - it will either use the actual depth from the Transducer to the sea bed or it will use the waterline offset if one is provided. This is dictated by the Navionics logging software and not associated with Raymarineoffsets.

regards

[moki38]

Then why is Sonarchart Live, using the Normal depth transducer, displayed depth to calculate the depth displayed on Sonarchart live. While the Sonar is displaying a complete different depth?

And yes, its using the normal depth and not (as one would expect) the sonar depth.

So in 2.5 meter water, the Sonar will display 2.5 meter water. At the same time, the normal depth will show 0.7 meter water (as this is set to below keel)
And thus, Sonarchart Live, will display on the chart a depth of 0.7 meter.

So the sonar knows the real depth, but Sonarchart live, will use the 0.7 meter.

So this is either a bug, Sonarchart Live is using the wrong depth. Or it is some kind a safety feature, Sonarchart Live, uses the smallest depth reported in de system.

Either way, i would like to have Sonarchart Live, use the Sonar Depth.

[Derek - Raymarine - Moderator]

Hi moki38

Many apologies - I have misunderstood your description of what you are seeing on the screen, I should have asked for a screenshot sooner!

Please allow us to test out what you have reported and I shall confirm back to you our findings in the next day or so.

Regards
Derek

[moki38]

Hi Derek,

Any updates?

Regards,
Moki38

[Derek - Raymarine - Moderator]

Hi Moki38,

Sorry, not yet, I have to wait for the engineers to release some time on our test boat, I have chased several times and will update you as soon as I hear from them.
Regards
Derek

[Derek - Raymarine - Moderator]

Hi Moki38

We have checked into this with the current AXIOM software and I hope I can explain this for you.

Lighthouse 3 works slightly differently to Lighthouse 2 and this was why I confused the issue - apologies for that.

AXIOM displays the 'System' depth on the digital display shown on the screen AND on the Sonarchart live graphical display. So when the i70 is set as a system data master, the offset applied to it is used in the AXIOM and is also applied ( As you correctly said) to the Sonarchart live - hence the red Sonar trail generated on the sonarchart live graphical display.

On the AXIOM, you can set a -ve offset, to identify a depth under the keel, however, to try to make this easy (!) we call it a keel offset and dispense with the -ve annotation, just displaying a +ve integer but applying the -ve value 'behind the scenes' to apply the offset correctly.

With your situation, one possible option is to select the AXIOM Sonar as the data master - this will then use the Sonar data throughout the network.

Alternatively if you wish to set separate depth offsets and use the DST800 you would need to isolate the AXIOM from the rest of STng and operate the AXIOM with one preferred set up and the i70 with the other - this would likely be more confusing, but you may prefer that?

Does this help at all?

Thanks
Derek

[moki38]

Hi Derek,

Thanks for confirming my findings.

I tried this, last weekend. But this will make the DST800 absolete. The i70s will just display the Sonar depth. Thats the same as both having the same offset.
Just that now, we are only using one sensor.

I think, this will create a 2nd system. 1 for Sonar (Axiom) and one for Wind,Depth and Speed (The i70s). But then either one of the i70s has to be dedicated to depth display or the data from the wind transducer cannot be displayed on the Axiom. Not sure what this will do to the vectors and drift/SOG...

It does give options, just not a workable/real solution.

[Derek - Raymarine - Moderator]

Hi moki38
thanks for the feed back.

The option which renders the DST800 obsolete, gives you the option of having consistant depth displayed throughout the network, so which ever display is viewed gives similar information and would be less confusing ?

Retaining the DST800 gives a good backup if you were to ever use the system with the Sonar turned off.

thanks
Derek