Topic: Yet another transducer mounting question

[asm]

I know, I know,  This is just what we need.  Another transducer mounting thread.     I think we should start a new section and fill it with picture of known working location/configuration to mount SI transducer on various type of boats.  Until then, here is few pictures of my transom.

Considering this is a Inboard/outboard boat, the part of the outdrive (transom mount) will always be in the way of the SI beam.  That's unless if I mount the SI transducer closer to the keel.  Dare I say, less than 15" from the prop arc as recommended by HB.  In my case, I think the best I can do is about 8.5" from the prop arc and with the SI transducer mounted about the same height, or slightly above the anode on the bottom of the upper outdrive unit.

Please take a look at the pictures and offer any educated guess as to how much of the SI beam is going to be blocked in the taped location.  I would preferred no blockage at all, but in the interest of not spending another $250 for another transducer for the startboard side, I can live with partial blockage, if it's not too bad.

If the shown location is too close to the prop arc, I can move another few inchs out, but it probably will worsen the blockage of the SI beam.

Thanks!!

[asm]

Hmmm... No one has any suggestion/speculation/guess?

How about this, if I mount the transducer at the taped location, Am I going to be able to see any thing at all on the starboard side?

[George]

asm

Wow it looks pretty close as to whether or not the transducer will see both sides.  Given that to use side imaging you will need to be going 5 mph or less, sometimes a little higher speed.  With Down imaging and Side imaging at about 5 mph you could trim the motor up a bit and see both sides with the transducer and that should work.  For the 2D it should work fine, you should just remember to trim the motor up a bit when you want to use SI or DI.

I would put the transducer as low as possible but high enough to protect the transducer.

If any others have an idea please chime in.

George

[asm]

Thanks!! 

I'm more worry about the the anode that is attached to the transom mount.  Outdrive is not much of worry as the picture shown is the worse case scenario where the outdrive is trimmed all the way in.  I doubt I ever drive the boat like that. 

[newkid4si]

asm
   Here is a suggestion on testing your chosen location without drilling any holes in the hull.
   I took a 1" X 3"  X 1/2" piece of oak  long enough that when the transducer was
   attached to one end, the other reached the top of the transom. I attached the top with
   a "C" clamp.
   I realize that the distance between the transducer and the motor will be reduced ( front to back ),
   but if the motor is tipped slightly, you'll be close.
   Another advantage of this method is that , depending on transom style, you may be able to move
   it closer to or away from the keel.
   If you try this, it helps to pre drill the screw holes and use shorter screws than are supplied.

            Mike
 
 

[asm]

Interesting suggestion. 

However, it's probably not going to work in my case.  The picture doesn't show it, but there is a swim step that covers the full width of the transom. 

I gathered from another thread that Greg had posted. He suggested using some sort of marine grade high bond double sided tape the test mount the SI transducer.  It's not mean for high speed operation, but idle around in the calm water at 2MPH should be just fine. 

Greg, if you are reading, where can I get this "marine grade high bond double sided tape"  Is this the same as the 3M outdoor double sided tape here?

http://www.amazon.com/3M-Scotch-Exterior-Mounting-60-Inch/dp/B00004Z4BV/ref=lh_ni_t

[Humminbird_Greg]

No that stuff is rated for only 5 pounds so I don’t think that it would be strong enough.  Try something like the 3M 5252:
http://solutions.3m.com/wps/portal/3M/en_US/Converter_Solutions/Home/Prod_Info/Prod_Catalog/?PC_7_RJH9U5230GE3E02LECIE20GER4000000_nid=T7HTMPNW0Dbe4Q43M9FFQ2gl

[asm]

Thanks Greg!!

I didn't find 5252, but perhaps you mean 5952.  In any case, that's very impressive specification.   22lb per square inch for 90 degree peel on SS.  Assuming the adhesive have the similar performance on gelcoat, and with typical application of at least 4 square inch when mounting a transducer (88lb), I think I need to worry about how to get it off without damaging the gelcoat when the testing is done.   

While I have your attention here, care to guess what my SI view may look like if I mount the transducer in the taped location?  As I have mentioned before, lower unit will likely be tilted further away from the transom while in operation.  I'm only worry about the anode that sits on the under side of the transom mount.  My guess is I may see a small partial block of the edge of the starboard side SI return.   Since you have been mount transducer longer than I have been playing with the 898SI, it would be nice for you to confirm my "guess".

By the way, I do have the another SI transducer mounted on a Bass Tracker.  For a almost flat bottom hull style and a outboard motor, the set works beautifully on Bass Tracker. 

[Humminbird_Greg]

Uhhh, yep.  Another typo on my part.  5952 is the correct one.  Don’t go believing that 22lb specification either.  I’ve bend tools trying to pry transducers off of boats after this stuff sets up!  I’ve mounted many things that ended up being more permanent than temporary.  Just be sure and prep the surfaces you will be installing it on.  I think I have some instructions I wrote at some point in the past… they are attached below.

I would guess that you will have partial blockage of the right Si sonar beam.  How much though I don’t know.  You will probably see the constant white lines in the Right Si sonar up next to the zero/surface line.  These will also show up in the Di sonar as well.

Mounting the transducer closer and therefore lower on the transom may help with the Si sonar blockage but it will also make it more likely that the transducer hits something and that it could create problems with the water flow through the outdrive due to cavitation.  No way of knowing without mounting the transducer there and testing though.

[asm]

Thanks for the instructions.   I'll give it a try this weekend.   

Now, I still need to pick a probable location that's going to work.   I'm thinking mounting another inch away from the prop like shown in the picture, but instead of mounting at the suggest height, I'm to be mount it lower to allow the transducer to "see" pass the out drive. 

So, besides creating a rooster tail, which is a none issue for me because of swim step, will mounting the transducer, say 1" below the hull cause any problem with SI, DI, 2D reading?

[Humminbird_Greg]

No it shouldn’t.
It will be more exposed though and so be more susceptible to damage from floating debris, trees, stumps, rocks,…

[asm]

It will be more exposed though and so be more susceptible to damage from floating debris, trees, stumps, rocks,…

Great!!

I have also been searching high and low for the actual beam width of the 455KHz and 800KHz SI beam.  As it turns out, it's right on the HB's web site -  86 degree and 55 degree.   Considering the beam width, especially in the 800Khz mode, I'm guessing I'll more than likely going to be alright mounting the transducer at the marked location.  For 455Khz mode, I'm hoping there are some overlap between the left and the right beam at the center, which may lessen the requirement of clear line-of-sight on the either side of the transducer.   

By the way, I did ordered some of those 3M VHB tape you mentioned, oh boy!! are they expensive!!   $45 a roll from Amazon!! 

In any case, I'll be test mounting the transducer this weekend using the 3M tape and report back to see how it goes.  Thanks!!

[asm]

Believe or not, we here in California have gotten so little rain for the past winter that ,u favorite local lake's water level is down about 85 feet from its normal level during this time of the year.   Before I left the house Sunday morning, I was told the water was low, but didn't realized that I could actually walk across the lake without getting my feet wet.   Needless to say, the plan to test the transducer had to be canceled.

The backup plan is to drive 2 hours to Long Beach, CA to test the transducer...  I'm sure they still got water in the pacific.