Author Topic: Transducer mounting problem? (Read 30290 times)

grey2112 · « **on:** June 19, 2012, 09:55:06 AM »

Just recently bought a Humminbird 1198c SI combo unit - does Side Imaging, Down imaging, and is a GPS.

Well, I think the transducer may not be mounted correctly. Here are the issues:

1 - I see some definite splash and spray coming off it when I'm going any speeds above 10 mph - it is especially noticeable when up on plane

2 - At various times the depth reading goes whacky - like saying I'm in 120 feet of water when I'm really in 3 or 4 feet of water. I have to come off plane, slow to a stop, and wait about 5 seconds for it to read properly again.

3 - When going at speed sometimes the sonar reading will get all weird - instead of showing contours and bottom it will show a bunch of "noise" and clutter.

4 - The side imaging on the port side is very limited - I think this is due to the side beam on that side hitting the lower unit of my motor - I suppose I can't do much about that short of either getting a jack plate, or not relying on the SI unless I am using my trolling motor and have the motor tilted all the way up and out of the water.

I'd really hate to have to get a through-hull transducer, but if I can't solve these issues I may have to.

Here's some pics and details of my current transducer mounting:

1 - From the outer edge of the prop to the port side of the transducer it is 10 inches.

2 - From the dead center of the prop (as well as dead center of the boat) to the port side of the transducer it is 17.5 inches

3 - When looking at the rear bottom of the transducer, it is 1.25 inches between the bottom of the boat and the bottom of the transducer on the starboard side of the transducer. It is .5 inches on the port side from the bottom of the transducer to the bottom of the boat.

4 - From the starboard side of the transducer to the first strake it is 7 inches. To the next strake it is 14 inches, and to the final curve/bend/outer edge of the boat it is 18 inches.

I have a 12" - 14" draft on the boat with a 19 degree deadrise.

Pics:

Humminbird_Greg · « **Reply #1 on:** June 19, 2012, 10:20:16 AM »

The best solution for #1 through #3 may be the inside-the-hull XP-9-20 transducer and XP-9-20 transducer. I say this because the normal solution for #1 is to raise the transducer upwards while the solution for #2 and #3 is to lower the transducer…

#4 you should be able to trim up the motor but should not have to put it into the trailered position.

Roddy · « **Reply #2 on:** June 19, 2012, 11:52:50 AM »

grey, Nice instal photos, that helps a lot.

With a 19' deadrise things can be problematic.
The next time you have the on the water trim the motor into the top speed position keep it in that position and load the boat onto trl.
Measure the distance between the tramsome and the motor,take some photo's and post.

All SI units inherently have a problem with reading at speed. As Greg stated the in hull transducer is the answer.

Roddy

Humminbird_Greg · « **Reply #3 on:** June 19, 2012, 01:02:43 PM »

Quote from: Roddy on June 19, 2012, 11:52:50 AM

All SI units inherently have a problem with reading at speed. As Greg stated the in hull transducer is the answer.

Not 100% true Roddy. It all gets back to the shape of the boat hull and where you can place the transducer.

grey2112 · « **Reply #4 on:** June 19, 2012, 01:41:14 PM »

So, barring somehow finding a way to fix the problem by repositioning my transducer, should I get the special $200 In-Hull transducer specific for the 1198cSI? Would that simply replace the transom mounted one?

Or could I get a normal 2d/Sonar in-hull transducer (about $75) and a cable and be able to switch back and forth between it and the 1198cSI transducer I already have? Meaning the in-hull one would be used at speed for 2d and depth, and then when I get off plane and trim up the motor I would use the HD SI/DI one?

Humminbird_Greg · « **Reply #5 on:** June 19, 2012, 02:52:45 PM »

I don’t think that the Thru-Hull XPTH-9-HDSi-180-T transducer is the answer that you need. I would first try adjusting what you have. Failing that, I would go with the XP-9-20 transducer and either the AS-Si-DB-Y cable or a TS3 Transducer Switch. Most just use the XP-9-20 + AS-Si-DB-Y cable combination.

grey2112 · « **Reply #6 on:** June 19, 2012, 06:11:58 PM »

Quote from: Humminbird_Greg on June 19, 2012, 02:52:45 PM

I don’t think that the Thru-Hull XPTH-9-HDSi-180-T transducer is the answer that you need. I would first try adjusting what you have. Failing that, I would go with the XP-9-20 transducer and either the AS-Si-DB-Y cable or a TS3 Transducer Switch. Most just use the XP-9-20 + AS-Si-DB-Y cable combination.

So, let me see if I have this straight - if I use the XP 9-20 transducer and cable, would both transducers work at the same time (2D and depth readings for the XP 9-20 and SI and DI for the one already installed?) And what would the Switch do for me instead?

Roddy · « **Reply #7 on:** June 19, 2012, 06:36:49 PM »

Greg, Try getting a Humminbird SI transducer to read a true depth at 25+mph sometime. You cant.

Acquire bottom-loose bottom-acquire bottom-read 978 feet- loose it-read 60feet-952'-loose it and on and on and on.

But I love using the it!

Roddy

grey2112 · « **Reply #8 on:** June 19, 2012, 09:54:16 PM »

Now I need to figure out which way to go:

Do I get a shoot-thru or thru-the-hull transducer and Y cable, or do I get a Sternmate to use with the current transducer in an attempt to fix the problem?

Does anyone know if the Key West 196 Bay Reef boats have a single hull or a double hull? If double, I don't think I can use a shoot-thru transponder.

grey2112 · « **Reply #9 on:** June 20, 2012, 12:01:30 AM »

One thing I have noticed in my research is that everywhere, including on Humminbird's site, it says to put the transducer further out towards the starboard side (lateral side away from the center) - like closer to the strake but not directly under it - like these pics:

http://www.humminbird.com/uploadedImages/Humminbird/Content/Support/FAQ/SeaRay-1.jpg

http://www.humminbird.com/uploadedImages/Humminbird/Content/Support/FAQ/SkeeterZX2050-1.jpg

But maybe that has to do with the type of boat and hull design.

So, tell me this - obviously the further outward towards the starboard side of the boat, away from the center, that the transducer is, the higher up in the water it is since the boat is not as deep out towards the side, correct? So the closer in towards the center on the transom, the deeper in the water the transducer is, correct? It appears to me that if I moved the transducer in towards the center, like a few people have suggested to me (like maybe 3 inches to the right of the big hull fitting just to the right of the drain plug) that it would always be much deeper in the water than if it were mounted at its current location, or even further outward towards the starboard side of the transom.

Does this have anything to do with the possible cavitation, rooster tails, performance issues, etc.?

Meaning, I'd have to have to keep drilling and filling holes to get this right -

sonar2000 · « **Reply #10 on:** June 20, 2012, 08:59:28 AM »

Quote from: grey2112 on June 20, 2012, 12:01:30 AM

One thing I have noticed in my research is that everywhere, including on Humminbird's site, it says to put the transducer further out towards the starboard side (lateral side away from the center) - like closer to the strake but not directly under it - like these pics:

So, tell me this - obviously the further outward towards the starboard side of the boat, away from the center, that the transducer is, the higher up in the water it is since the boat is not as deep out towards the side, correct? So the closer in towards the center on the transom, the deeper in the water the transducer is, correct? It appears to me that if I moved the transducer in towards the center, like a few people have suggested to me (like maybe 3 inches to the right of the big hull fitting just to the right of the drain plug) that it would always be much deeper in the water than if it were mounted at its current location, or even further outward towards the starboard side of the transom.

Does this have anything to do with the possible cavitation, rooster tails, performance issues, etc.?

Yes it all has to do with the above . But the farther out and less depth in water will then result in loss of signal.

these HB transducers are very sensitive to placement and operation regarding external influences.

You might try some sticky tape for tests. dont run at high speed but see where you might get the best placement.

Chuck

ITGEEK · « **Reply #11 on:** June 20, 2012, 10:00:09 AM »

I think I agree with Roddy.
Based on the sheer number of posts I've read about high speed
and transom mounted transducer problems.

I think that high boat speed and good transducer performance are just not compatible,
regardless of the transducer manufacturer.

Water turbulence over and around the transducer, and the fact that the
transom physically raises up in the water at high speed are just not good.

grey2112:
Install a transducer plate on your transom.
That way, you only need to drill two holes into the transom.
You can then move the transducer around as much as you like.

But, I think if you are looking for good transducer performance at
max boat speed, I think you are going to be disappointed.
You may get a depth reading from shoot thru the hull or
drilled thru the hull, but that is probably all.

Humminbird_Greg · « **Reply #12 on:** June 20, 2012, 12:30:28 PM »

Quote from: grey2112 on June 19, 2012, 06:11:58 PM

So, let me see if I have this straight - if I use the XP 9-20 transducer and cable, would both transducers work at the same time (2D and depth readings for the XP 9-20 and SI and DI for the one already installed?) And what would the Switch do for me instead?

grey,
If you use the XP-9-20 transducer + the AS-Si-DB-Y acble than the 2D sonar readings will always come from the XP-9-20 transducer, while the Si/Di sonar and water temperature will come from the HDSi transducer you now have installed.

The TS3 Transducer Switch allows you to select which transducer the unit will be using.

Humminbird_Greg · « **Reply #13 on:** June 20, 2012, 12:41:04 PM »

Quote from: Roddy on June 19, 2012, 06:36:49 PM

Greg, Try getting a Humminbird SI transducer to read a true depth at 25+mph sometime. You cant.

Acquire bottom-loose bottom-acquire bottom-read 978 feet- loose it-read 60feet-952'-loose it and on and on and on.

But I love using the it!

Roddy

Roddy,
Just because you have not been able to do this on your boat does not mean that it cannot be done. There are many that have and still far more who haven’t even tried as they install the more expensive to lose HDSi transducers up higher on the hull to protect them. The first HDSi transducer I installed was on our 2005 Skeeter ZX20 Bay Boat (see pic for location of transducer). First time without adjustment (I got lucky) it would read a steady bottom reading at WOT of 46 mph. Below is a Screen Snapshot from the 987 I was testing at the time – sorry but I did not grab a 2D sonar picture but this is of the original river channel that is in our lake. Does this mean that this can be done on all boats with all transducers (regardless of brand)? No it does not, but it does mean that it can be done on some boats.

sonar2000 · « **Reply #14 on:** June 20, 2012, 06:21:55 PM »

I think it is the newer transducers that have this speed issue. Not many of the folks I know have any reading above 10MPH.
This should be investigated in more detail by HB.
There is a number of users who have this problem as seen on several other forums..So it cant be an isolated issue.
Chuck

Bob B · « **Reply #15 on:** June 20, 2012, 08:10:54 PM »

I think Greg is right, the largest majority of people aren't attempting to mount their units for high speeed operation.......they mount if to protect the transducer during high speed running.

I have seen images posted on another forum with the transducer (current version) mounted just slightly below the bottom of an aluminum boat and are getting si readings in the upper 40mph range......virtually none of the boats going 70 have them mounted to get high speed readings.

sonar2000 · « **Reply #16 on:** June 21, 2012, 08:32:21 AM »

Bob, is exactly right. Mounting is everything...then we go from there..
Chuck

Humminbird_Greg · « **Reply #17 on:** June 21, 2012, 08:58:39 AM »

Bob B brought up something: “virtually none of the boats going 70 have them mounted to get high speed readings”.
I have not thought about in a little while but on boats going this fast a transducer dragging through the water at those speeds could cause boat handling issues – yet another reason for an inside-the-hull installed transducer. We had a guy here who had an Allison Bass boat (95+ mph boat!) and he couldn’t mount any transducer off the transom that drug through the water without causing severe handling issues.

Not sure what you are calling the “newer transducers” Chuck but nothing has changed in the design of our transducers that would make installing them for high-speed readings any worse than it has been.

sonar2000 · « **Reply #18 on:** June 21, 2012, 12:07:59 PM »

The larger si vs the small si..VS non si of past..
Chuck

Humminbird_Greg · « **Reply #19 on:** June 21, 2012, 12:29:17 PM »

Okay Chuck, I was not thinking that far back. The larger transducers are harder to install on boats for high-speed depth readings. I was thinking you were meaning some of the changes to the transducers for noise shielding as these have been the only changes to the transducers since they were introduced.

sonar2000 · « **Reply #20 on:** June 21, 2012, 01:01:03 PM »

Nope just the physical size change and of course shoot thru vs si.
Wow, just too much technology.

Chuck

ioski · « **Reply #21 on:** June 25, 2012, 07:12:43 PM »

You probably have already addressed your transducer issue, but...

For number one: on my old 365i's transducer; I had to put some rescue tape (self-fusing silicone tape) around that area just in front of the transducer between the metal bracket arms. The water was shooting up thru that space. I noticed that Humminbird included a rubber "transducer plug" on my 798ci unit. I think it would have had the same issue if it weren't for that plug.

For number four: yep, your lower unit is definitely in the way.

- ioski

grey2112 · « **Reply #22 on:** October 21, 2012, 05:21:44 PM »

OK, so I got a mounting plate and installed the transducer according to what the guys at Humminbird told me to do after I sent them this thread and these pics.

The problems I'm having NOW though is pretty frustrating.

The transducer is "popping" out of the water in even relatively calm seas - sometimes it happens just after I got up on plane, other times it takes 5-10 minutes of bopping along. It appears that the metal mount that the plastic transducer rests in (and is bolted into) has these two "ribs" that keep the transducer from popping up , but if it hits something hard it will pop up and swing out of the way - but once it does this it won't come back down and you have to manually push it back into the brackets.

So, apparently simply running around in easy seas is enough to cause it to pop out of the cradling ribs and I have to stop and push it back into place.

Could it be my mounting? Perhaps the way I have it mounted is putting it inline with a lot of fast moving water that is eventually pushing it out of the cradle and popping it up?

Possible solutions?

1 - Move transducer - either outward again, and/or up higher along the transom so that the water doesn't push over it so much, keeping it down

2 - Grind down the little cradles/nubs that hold it down - this of course would mean that it would be free-swinging, but then when I'm not going fast or the seas have calmed down it would swing back into place and be flat again and I wouldn't have to push it down manually back into the cradle.

3 - Put a screw/bolt/piece of metal behind the cradle to keep it from popping up at all - sort of locking it in place - though of course this could cause the transducer to get ripped off if I ever hit something underneath it.

4 - Ignore it and get a XP 9-20 shoot-thru transducer and rely on it for my sonar and depth readings and just use the other one for SI/DI.

Last pic shows what happens when underway:

Humminbird_Greg · « **Reply #23 on:** October 22, 2012, 03:42:44 PM »

Ultimately your best bet may be to raise the HDSi transducer up so that it isn’t dragging through the water at higher boat speeds and also installing the XP-9-20 transducer and an AS-Si-DB-Y cable; but you can try and work with what you have. I would try raising the transducer upwards about ¼ of an inch and testing it again. If it keeps popping up try raising it more… and so on. Before starting any more testing though, you should increase the pressure needed to pop the transducer up be slightly bending in the sides of the metal transducer bracket. Not much now, just a little.

sonar2000 · « **Reply #24 on:** October 22, 2012, 03:46:40 PM »

Be aware that as you raise the transducer you may start to lose sonar at speeds above 6 mph or higher. Depends where the transducer is as it relates to the hull.......
Another consideration is to have the transducer on a mounting braket that will let you raise and lower the transducer especially as it relates to your speed..
Chuck

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