Topic: Transducer placement

[squam]

New to the forum.  I have an ONIX 8 CI SI.  Boat is a 22" center console with an Evinrude outboard.  Salt water and mostly will use the unit in shallow conditions.  Was having all kinds of issues with the sonar until I noticed that the installer had crossed the wires from the two transducers into the Y cable.  Tech support told me they are labeled, but I couldn't find anything. The thickness of the wires was the only clue that they were reversed.  Fixing this got me up and running. 

The two stern mount transducers are mounted as follows.  DI/SI on the port side 12 inches or so to the left of the motor.  The 2D about the same distance on the right.  both are right at the level of the bottom of the boat per the instructions.  Basically at the exact same height. 

Problems as follows -- I welcome input.  SI shows clearly on the port side of the boat (same side as transducer), nothing but noise on the starboard side.  Have tried with the motor raised and no difference.  Is there a chance the 2D transducer location is the problem -- blocking the view to the right side?  Can/should I mount the DI/SI transducer higher? 

Initially was getting no reading from the 2D past about 10 mph.  I moved it 1/4 inch lower and now getting reading up to 25 mph +/-.  Above that, it loses the reading.  And since I moved it lower, the transducer is kicking up a ton of water.  Tech support is sending me an add-on piece that will apparently help with the rooster tail.  Should I move it even lower to get a better reading at full speed?  has anyone else used the add-on piece?   

[Humminbird_Greg]

Welcome to the Humminbird Side Imaging Forums squam.

What does the right Si sonar look like with the main motor raised up and the boat is drifting while in 20+ feet of water?
Can you post a Screen Snapshot of this?
Can you also post another of the same but with the SI Range menu set to 20 feet?

Do you know the model number for the 2D transducer?  If it is an XNT-9-20 or XNT-9-20-T the roostertail plug that the Humminbird Customer Resource Center folks are sending you should have been in the packaging.  It is used to block the area between the transducer and the mounting hardware so that water cannot flow over it and kick up that ton of water.

The starboard side 2D transducer is blocking some of the right Si sonar but we need to determine if this is the overall cause of the right Si sonar problems or if there is something else going on here.

[CarolC]

We had ours mounted higher for the same issue, our boat is a crestliner sportfish- We just have to trim a  little and we do get both sides.

[squam]

Thanks Greg, I'll post some shots in a day or two.  Trying to dig up model numbers of the transducers from the yard that installed it.  I am quite sure the 2D is the one that has 83/200 frequencies.  Called tech support this AM, and was told that it's most likely the 2D trans on the right side that is blocking that half of the SI picture.  They are mounted at almost exactly the same height.  They said I should move the SI/DI lower than the 2d to be sure it's not blocked.  That makes sense and I think I'll be able to lower it, but have to check. 

Couple other questions:  Where does the tide data come from?  The unit is finding the nearest station, but the tide data is not even close to correct. If it comes from the map card, I have a Navionics gold which I just bought, so I assume that would be up to date? 

finally, this is a brand new boat that has a noticeable list/lean to port (right side rides quite a bit higher than the left) at high speed that we cannot seem to figure out.  One theory is that the 2d trans is functioning as a mini trim tab and pushing the right side higher.  Any thoughts on that?  I'm going to test it by snapping the trans up and out of the way, but just wondering if anyone has experienced anything similar?  I'm dubious that's the cause, as the SI/DI trans on the left side is much bigger and also currently just below the level of the bottom of the boat.  I think it's the engine mount...

[Humminbird_Greg]

squam,
The model numbers of the transducers should be on the cables themselves.  There should be bands within a few feet of the connectors that has this information printed on them.

We need to see how much of the right Si sonar is being blocked by the 2D transducer and make sure that something else is not also happening at the same time.  With the transducers being about two feet away (24 inches) from each other the 2D transducer cannot be blocking all of the right Si sonar beam as the Si sonar projects outwards and downwards.  The 2D transducer could be blocking the Si sonar when in very shallow water but not when in 20 feet of water.  This is why I requested the Screen Snapshots that I did.  Ideally the HDSi transducer would be lower than or fore/aft of the 2D transducer but this is not always possible on all boats.

If you can (I’m adding a few more here) can you take some Screen Snapshots and post them back here?
 - Motor running at idle speed, motor all the way down, 20 feet of water, SI Range set to 40 feet.
 - Motor running at idle speed, motor all the way down, 20 feet of water, SI Range set to 20 feet.

 - Motor off, boat drifting, motor down, 20 feet of water, SI Range set to 40 feet.
 - Motor off, boat drifting, motor down, 20 feet of water, SI Range set to 20 feet.

 - Motor off, boat drifting, motor up, 20 feet of water, SI Range set to 40 feet.
 - Motor off, boat drifting, motor up, 20 feet of water, SI Range set to 20 feet.

 The tide data comes from the mapping card.  I suggest you check the time of day that the unit is showing and set the Time Zone and Daylight Saving Time menu settings if it is not correct.

That small XNT-9-20-T transducer would not have the ability to lift that side of the boat.  If it did, the larger HDSi transducer would more than make up for it.  I have seen where a smaller transducer like the XNT-9-20-T can cause planning issues but this was with an Allison Bass boat (ultra-light and ultra-fast!).  Besides, if the 2D transducer, which is mounted on the right side of the motor, was causing this it would cause the right side to be lower in the water due to the water it is kicking up (and therefore the transducer is getting pushed downwards).

[squam]

Thanks -- will get my homework done and get back to you .  Seriously, I really appreciate the help.  May be a couple days before I can post those shots.  I'm up in the Boston area and we are expecting some sketchy weather including the first tropical storm of the season -- looking like a near miss, but will will likely keep us on shore through Friday.

Just to be sure I understand it -- to set the range, it looks like I open the xpress menu on the SI page, and set the range toggle to manual, then move the slider over to 20/40? 

And regarding my high speed problem -- I'm losing my depth reading from the 2D trans above ~25 mph (max for the boat is 35-ish).  Will that little piece they are sending help with that or do I need to lower the trans more?  I've already lowered it about 1/4" and it got me to a higher speed before I lost the reading (up from 10 mph).  I can easily slide it a little lower if you think that would help.  Or should I change the angle?  It's parallel to the bottom at the moment. 

And I totally agree with your comment on the leaning. Has to be the motor or some other issue. 

[Humminbird_Greg]

I hear you on TS Arthur squam.  I figured he would mess with many a persons Independence Day festivities.  No problem in getting back next week as I may not be on until then since it is the holidays and I’m sure my Wife has something really fun for me to do like help clean the bathroom or mow the lawn…

Yes, the SI Range menu is in the Si sonar X-Press menus.  Just set to to the 20 and 40 foot settings.  The 20 foot settings will allow us to see if there is any reflected Si sonar.

The roostertail plug that they are sending you can affect how the transducer is reading (better or worse is a toss-up) as if keeps the water that was flowing over the transducer body from doing so.  If this water gets redirected under the transducer and if it has air bubbles in it; then the unit will not read as well at those boat speeds.  Generally you need to drop the transducer down lower and/or put a slight downwards angle on the back end of the transducer to help it read better at higher boat speeds.  This is all assuming that it was installed in the best location to begin with.  Ideally this is a location that has little or no air bubbles flowing off of the boat hull at higher boat speeds.  This would not be behind any sort of projections from the hull (rivets, weld marks, strakes, water intake/drains,…).  Which one or what combination works best for your boat can only be determined with successive (small) changes in the height and angle of the transducer.

Question: is there any reason why you did not opt to install the 2D transducer inside-the-hull of the boat?
This is a fiberglass boat correct with a solid fiberglass (not a wood/foam cored) hull, right?
Being able to install the 2D transducer inside-the-hull would allow for the best high-speed depth readings and it will put it forwards of the HDSi transducer, so it can’t block any of the Si sonar either.

[squam]

Well, believe it or not, it is a 100% wood construction with a thin fiberglass skin over the bottom.  If you are curious, go to landingschool.edu and look for information on the Flyfisher 22.  If I could mount the 2D inside, I would consider that, but I'm guessing it won't read through wood? 

Enjoy the holiday and I'll post some follow-up when I can get out.

[squam]

The storm arrived later than we thought, so got out this morning and did some testing and have images.  I did a few more in addition to the ones you requested.  Hope these get posted properly.  Instructions are a bit confusing.

Range: 40
motor at idle speed; down all the way
attached jpeg file ends in 513 -- seems pretty good on both sides


Range: 20
motor at idle speed; down all the way
files ending 711, 745, 824.  Basically all of the tests with the range at 20 were problems.  either totally blank, or like these after a minute or so.




Range: 40
motor at idle speed; tilted up
301.  Also pretty good.


Range: 20
motor at idle speed; tilted up
506, 558.  More of the same.  No good.



Range: 40
drifting, motor down
705.  Pretty good on the left but no so good on the right.


Range: 20
drifting, motor down
945.  nothing at all.


Range: 40
drifting, motor up
202.  Pretty good on both sides.


Range: 20
drifting, motor up
326.  Nothing.


Generally with the range set at 40 or auto, I feel like the unit was working pretty well today.  I moved the 2D trans a bit lower before I went out and I'd say the 2D is now about 1" below the DI/SI.  Perhaps that has helped?  I also installed the rooster tail plug, and that definitely fixed the spray issue.  Now I'm getting readings at full speed most of the time, but not 100%.  Do you still recommend tilting the 2D down at the back end? That would make it definitely not parallel to the bottom of the boat. 

Also -- here's what I can tell you about the transducers. I am still not 100% sure on the exact model numbers, but I think these are correct.  Hoping to confirm with the yard on Monday.  2D -- I think it is XNT 14 20 T.  On the cable there are two lines of numbers -- top line: 490419-1(X1) and bottom line:  1113.  DI/SI -- I think it is XT 14 20 HDSI T.  Cable also has two lines.  Top line 490410-1(X5), bottom line 0413.

[squam]

I installed the latest software update and was out yesterday. The readings seem to be better at all settings -- now I just have to figure out how to interpret them!  I was only running with the motor at low speed and fully down, but I seem to be getting readings even with the range set at 20.  So the SI seems much better at the moment.  If you have any suggestions based on the above images, I would welcome them.

Still getting intermittant loss of signal at high speed though.  I can either push the 2D transducer a smidge lower (pretty close to the bottom of the slots already, and I'd rather not re-drill if I don't have to) and/or angle the back of it down (which will make it not parallel with the bottom of the boat).  Suggestions?

Also, can you tell me what type of NMEA 2000 cable I need for this unit?  I have searched all over the Humminbird site and cannot find anything.  Bought a generic one at West Marine, but the end that would plug into the unit is not threaded so it won't connect. 

Thanks.

[squam]

Found a Garmin cable on Amazon -- will this one work?

http://www.amazon.com/Garmin-NMEA-2000-backbone-cable/dp/B00183QWK0/ref=sr_1_1?ie=UTF8&qid=1404733686&sr=8-1&keywords=nmea+2000+cable

[Humminbird_Greg]

squam,
Is this for the NMEA 0183 or NMEA 2000 connection?

[squam]

nmea 2000

[squam]

I was able to confirm one bit of info on my transducers.  The 2D is an XNT 12 20 T.  I have not been able to confirm which of the DI/SI transducers I have.  As noted earlier, I think it is the XT 14 20 HDSI T, but it could be the other one listed in the installation manual -- XT 14 74 HDSI T.  Did the numbers on the cable (top line: 490410-1(X5), bottom line: 0413) tell you which one it might be? 

[squam]

Humminbird tech support confirmed that my SI/DI transducer is the XT 14 20 HDSI T

[squam]

Greg -- I think the SI/DI images are pretty good but I'm still having two issues with my unit. 

1 - losing the sonar at high speed after sliding the 3D transducer down as far as possible with out re-drilling. Do you recommend tilting the back of it down a notch even if that will make it not parallel with the bottom of the boat?  And at speed, with the bow up, it will definitely not be parallel with the sea floor. 2d trans is model # XNT 12 20 T

2 - my Navioncs gold chart card is reading the wrong time on the tide charts.  Have checked that my unit has the right overall time offset and DST setting.  The unit is finding the correct local tide station and reading tide data, but it's roughly 6 hours off.  Have put a ticket in with Navionics but they say it is likely a problem with the Onix.  Is there some other time setting that I need to adjust within the unit to make this work?

[Humminbird_Greg]

Yes, if you have the 2D transducer all the way down try slightly tilting the back end of the transducer downwards.  This may not make it parallel with the surface of the water but it may be the only way to get better readings at high boat speeds.

I’ll have to ask around about the time on the tidal charts.

[squam]

Here is some additional information. First is a picture of my card info from the Humminbird Onix.


Second is a screen shot of the tide information that was displayed on the Onix on July 11th at 7:11 p.m. 



The correct tide data for this station yesterday can be found on any number of web sites. Here is the correct data for July 11th.

am low 4:55; -.65 feet
am high 10:58; 9.48 feet
pm low 5:03; -.03 feet
pm high 11:11; 11.3 feet

So at 7:11 pm it was about 2 hours past the pm low. I had about 1.5 feet of water under the transducer at the time and the tide was obviously coming in.