Topic: Mounting Transducer on Tiara Continental

[ScottT]

Hello,
I just received my 898c HD SI combo and can't wait to get it installed and working.
I was looking at the instruction sheet a couple days ago online and I am now wondering where I need to mount the transducer.

I have a 9.5 foot width, with twin inboard/outboards.   When I first purchased it, i was assuming I'd just mount it in the center of the transom.  After reviewing some posts on here and online, I am now wondering if the outdrives will cause interference.

There is a 32 inch span between the outdrives, therefore if I mounted close to center (due to drain plug), I'd have about 13 inches on one side and 19 on the other.  The outdrives are approximately 4 inches off the transom.

So my first question would be is that acceptable clearance and would a transom mount be acceptable?

If not, I'm not opposed to doing the through hull setup.  But that leads me to other questions. 
First being.. it looks like the thru-hull unit would be about 2 inches thick on the underneath of the boat - does this impact anything?
Next would be where to mount it.  I looked at that manual also it it states for twin inboards you would want to have 2 transducers, however nothing is stated about twin IO's.  I'm thinking it would be mounted centerline of the boat about 3 foot from the transom.

Any help would be appreciated - as i would like to get this right the first time. 

Pictures of the transom are attached.




Thank you for your time!
Scott

[Humminbird_Greg]

I’m hoping that someone else who has a similar boat hull and setup will chime in here…

With only four inches of clearance between the transom and the outdrives of your I/O’s, you will be blocking the left and right Si sonar if you center mount it on the transom.  The standard transducer that comes with the 898 units needs seven inches of clearance between the transom and outdrives to ensure no blockage.  Installing two Si transducers on the transom (outside of the outdrives) may not work either due to the trim tabs – but I really can’t say that for sure as I can’t see how far down on the transom they really are nor how far down you have to run them.  That may be an option though.  You will need the AS-Si-LR-Y cable for this.  Personally I would try mounting only one transducer and see if you get any blockage before spending the money on two and the Y cable and finding out the Si sonar is still blocked.

For a Thru-Hull transducer I think that you would have to mount it under the keel for best results.  You don’t have to use the included fairing block on the outside of the hull so you will only have the transducer sticking out 1.3 inches at the most (it actually tapers from the front to the rear).  I’m sure that this would produce some drag on the boat itself and you would have to watch when trailering or when hauling it out of the water so it does not get damaged.

[ScottT]

I think i'm leaning towards the thru hull option. 
Anyone else using the thru hull option?
The bottom of the boat is pretty flat so i think i could mount just the transducer on the outside and use the fairing block on the inside for the extra width needed by the nut.
I called humminbird and the will exchange the transducer for no charge (expect my shipping cost to them) so that is good.

I'm going to go down and look over the boat this weekend to make sure i have access to where i want to mount it.  I'm thinking about 3-4 feet back from the transom to leave room for the lift straps and blocking.

[Humminbird_Greg]

ScottT,
Just remember that location has to still be in clean water (no air bubbles) when the boat is underway.

[ScottT]

Greg,
Thanks for the replies.  So what you are saying is not to get to far forward, correct? Otherwise on full plane or rough water the transducer can leave the water. Just want to make sure I understand.
I have to look at the boat again and see how far forward it stays flat.  I just want to make sure there is enough room for the straps and blocking. I'd hate for the lift strap to snag it during hull out because I put it too close  to the transom. Thanks again.
Scott