Topic: transducer mounting - please help

[doc_d]

I have a 14 foot aluminum StarCraft with a 25 horse outboard.  I just bought a 798ci and want to get it mounted.  I bought a transducer mounting plate to give me some flexbiity to move the transducer around if needed.  Here's my conundrum.   If I hold the transducer between the transom and the motor it just fits.  So I think if I mount it without the plate I'm pretty sure the motor won't block the side scan signal.  If I use the mounting plate it will push the transponder about 3/8" further back which means it would be overlapping the motor by 3/8th of an inch.

So do I use the plate which would allow me to move the transponder but risk side scan being blocked.  Or do I skip the plate but then risk having to drill multiple holes in my transom if the original position doesn't work well?

Thanks!
Doc

[newkid4si]

doc_d

      My vote is to use the mounting plate and if need be, tilt the motor.
     
                 Mike

[doc_d]

Thanks Mike!  I'll use the plate.   The last question I have is about the proximity to the motor.  The humminbird instructions say to mount at least 15" away from the motor.  That puts me on a strake.   Once I move past the strake I'm about 10" from the edge of my little boat which means I'm pretty high on the dead rise.

I see many people (including youtube videos from humminbird) where they mount the transducer just a few inches from the motor.  So that's really confusing.

I have two concerns about mounting so far off to the side.  Being so high up on the dead rise the transducer is inline with the live well strainer thing on the transom which could block the SI beam.  Also being so high up on the dead rise makes me think that waves may cause it to come out of the water.

I'd appreciate any input.

Thanks!
Doc

[Bob B]

The other option to the plate would be to use some industrial strength double stick tape....That way you can test and move around without drilling holes.

Only use for low speed testing and make sure you have a safety cable on the transducer to keep it out of the motor if it comes loose.

Greg will be able to answer your distance from the motor question.

[rnvinc]

The 15" clearance stated in the manual is more for stop-to-stop clearance of the motor's maximum travel capacity side to side..

Rickie

[Humminbird_Greg]

The 15-inch rule was originally added to the transducer installation instructions for those boats that have an inboard motor where the propeller is typically forwards of the transducer.  The propeller can cause air to separate from the water and flow across the transducer which will not allow it to work.

Now if the transducer is mounted directly in front of the motor and/or propeller it can cause a problem in two ways: when underway and usually only at higher boats speeds, an air cavity can form behind the transducer which may not allow for proper water flow to the propeller causing it to slip or spinout.  This air cavity if it reaches the cooling water intakes of the engine can cause overheating issues as well.  Not all boats experience this and unfortunately the only way to know for sure if either/both of these will happen is to mount the transducer and test it.

As Rickie referenced though: you have to allow room for the full left-right turning capability for the motor too.