Topic: Thru hull si transducer on aluminum keel?

[Rotus623]

Hey guys I have a 998c si. I was looking at the transom and the skeg is going to be in the way of the ducer if I mount it on the transom. Have any of you guys mounted the plastic thru hull si ducer in the keel of the back end of any aluminum boats? The dead rise is high enough that if I mount it directly in the center my si will have plenty of clearance. I posted a pic of my Starcraft, do you guys think it will be a good idea to trade my transom mount for the thru hull? It would be a crime to drill through my precious aluminum if it is going to be less than ideal. I'd like to avoid mounting two transducers because it is expensive and doesn't look good in my opinion. http://i803.photobucket.com/albums/yy317/rotus623/Boat%20Restoration/P4291144.jpg

[newkid4si]

I would not be drilling a hole in my aluminum boat.
Scroll down to the bottom of this post to see how I mounted my 998 transducer on a aluminum boat.

http://forums.sideimagingsoft.com/index.php?topic=4764.msg29554;topicseen#new

If you have power T/T, just slightly raising the motor should get you clearance for the SI beam.

           Mike

[Rotus623]

While that is innovative, the skeg of my motor will still be in the way if I did that. That is my main concern, but I agree drilling a hole in aluminum is less than ideal.

[newkid4si]

How much clearance do you have between the transom and the front of the lower unit on the outboard?

         Mike

[reddog]

Mount it where the two white spots are to the left of where it is shown now.
   What have you  got to lose?  A little time? 
Can you take a side shot photo of your transom/motor.

There are thousands of transom mounted installations, Im having a hard time seeing why yours will hit the motor..

[newkid4si]

Mine was originally mounted as reddog suggest.
Normally I have one or two people on-board and the port/starboard level was OK.
But with a third person, the transducer was tilted enough to affect the image.
So I decided to make something that I could adjust to any situation I had.
My imagination took over and that is what I ended up with.
You don't have to step off the deep end like I did; just know you have options.

             Mike

[Rotus623]

Thanks mike.  And reddog thanks for the input. I heard that I need about 4.5" between the transom and the lower unit. Does that sound right?

[newkid4si]

I think the preferred distance is 6 inches.
The side beam width is about 4 inches.

Do you have power tilt/trim? 

[Rotus623]

No power TnT. ThAt is why there is a placement issue... 

[sonar2000]

You might consider mounting your transducer on a verticle shaft (like the shaft on a portable trolling motor) and use a Ray mounting bracket for the transducer. That way you can position it where you want and tilt it accordingly to the way people are sitting (fishing) in your boat..
I will get a picture of ours and post here..
Chuck

[sonar2000]

Here is a picture of our portable mount. You can tilt it forward or aft .....or left to right...

Chuck

[Rotus623]

That's pretty innovative 2000. Does it hold still when you are under way?

[sonar2000]

Yes, but we dont use it at speed. Most of the time 2 to 5. If we go to plane speed we raise it up. The whole setup does not cost all that much and I have not been on a boat yet that we could not put it on.
Chuck 

[LocDown]

haha. looks like a BPS Pond Prowler transom trolling motor ..or what's left of it.

Is the shaft big enough for the connector to feed through the length?

[sonar2000]

Yes the connector will fit thru the shaft.  We left it on the outside. the shaft and mount are a standard replacement parts available thru any boat dealer. We ordered the Ray bracket for the transducer to make it easy to put on. 
Works well as a portable system and as I said it fits almost any boat. 
Chuck

[Rotus623]

So I guess you just don't use a sounder at higher speeds?

[sonar2000]

This arrangement is used portable in search and recovery, and generally on someones elses boat.. For speed soundings we will rely on what ever the boat has installed.
Our boat does have sonar for speed but it is not the HB brand...

Chuck

[reddog]

Rotus,

Post  a side angle photo of your boat and motor..please..

It cannot be that different than any other tin boat..   If the motor has no tilt/trim, then there has to be adjustment holes/pin to adjust the pitch of the motor..  If its pinned down to the transom, I cant imagine that is your best performance option..

[Rotus623]

Red oddly if it is just me and one other than the boat porpoises at half throttle or over, unless the motor is trimmed as shown. If I have three people than I canoe the motor up one or two pins without porpoising. I was trying to get a new prop but can not get my tiny tach to give me a good WOT run. What a pain.....

[reddog]

Rotus,

Give Ricky a email at www.brainerdprops.com

Tell him what you currently have for boat, motor and prop and he can make a recommendation.

What you are doing now, is basically driving the nose of the boat into the water to eliminate the porpoising, which also puts a large amount of drag on the boat, leading to poor performance..

They also have a 14 day trial period to try props, (if they have your prop in stock) 


He is a master at figuring this stuff out.

[sonar2000]

As Reddog had requested, is it possible to take a  couple of pictures of your boat. The transom for the transducer mounting, the boat inside for loading and weight..
Pictures help us see exactly your setup or condition..

Thanks, Chuck