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Author Topic:   Transducer Mounting on Montauk 170
timsr posted 06-29-2005 07:31 PM ET (US)   Profile for timsr   Send Email to timsr  
I know that there are several topics on transducer mounting but before I go and drill holes in the transom I just want to make sure of a couple of things.

Does it matter if I mount the transducer on the port or starboard side. I am plan on installing a 6 hp aux motor later on in the year and since I don't have a swim platform my options for the aux motor can be either side but I am leaning to having it mounted on the starboad side. I just want to make sure that if I do that should I install the transducer on the port side? The manufacturer's(Humminbird) installation instructions state that if you have a prop that turns clockwise then there is more turbulence on the port side of the transom. This is the reason for my concern.(I am making the assumption that my 90 hp 4s Merc's prop turns clockwise)

The other question is on the transducer itself, how deep should it be in the water both at idle speed and at planing speed. Maybe if someone could take a measurement on their installation and let me know that would be helpful.

Any suggestions would be appreciated. Thanks

I'm really enjoying my new Whaler and this forum makes it all that more enjoyable.

Barney posted 06-29-2005 09:24 PM ET (US)     Profile for Barney  Send Email to Barney     
Here is a general idea for location. I used the transducer manufacturer's provided template and recommendations for depth and location. It works well. Jim
bigjohn1 posted 06-30-2005 08:32 AM ET (US)     Profile for bigjohn1  Send Email to bigjohn1     
timsr, as to the "depth" to which your transducer is meant to extend below your hull, that should be spelled out in the installation instructions supplied with your transducer. Since so many of us have sonar units from a variety of manufacturers, its best to go with what your manual calls for. Mine is 1/2" for my NAVMAN but that might not be correct for your unit.

One thing I have learned from my own limited experience and that of many others is that you are never going to get the absolute best performance from ANY transom-mounted transducer. About all you can do is install it per the manufacturers specifications and then "fine-tune" the tranducer depth per the limits of your transducer mounting bracket. That said, they will work fine for most applications and show good returns as long as your not going too fast or running in mega-rough water. FYI, if you want the best transducer performance on a Whaler hull (excluding in-hull transducers) you might want to try one of those new angle bracket tranducer designs. I don't know much about them personally but have seen numerous threads on the Hull Truth about them. Those who have them say they are much better than standard transom-mount transducers.

bsmotril posted 06-30-2005 08:57 AM ET (US)     Profile for bsmotril  Send Email to bsmotril     
It does matter what side it goes. To minimize the effect of the prop, it should be on the starbord side for a clockwise turning prop. There, the prop blades are going down, away from the transducer, and their shock wave won't cause flaky readings. The instructions for the Raymarine transducer I just mounted last night point this out, and also say it should be at least 3" away from the turning radius of the prop. so, with my 13" prop, it must be at least 9.5 inches away from the center line. The closer it is to centerline, the better it will work when you turn to port and that side of the boat rises out of the water. BillS
timsr posted 06-30-2005 02:45 PM ET (US)     Profile for timsr  Send Email to timsr     
Does the prop on my new 90 hp 4s turn clockwise or counter clockwise.
Chuck Tribolet posted 06-30-2005 03:41 PM ET (US)     Profile for Chuck Tribolet  Send Email to Chuck Tribolet     
FWIW, my transducer works better on the port side than the
starboard side. Humminbird instructions said port side.


bsmotril posted 07-01-2005 08:53 AM ET (US)     Profile for bsmotril  Send Email to bsmotril     
Your Fourstroke has a right handed, or clockwise prop. BillS
timsr posted 07-01-2005 11:10 AM ET (US)     Profile for timsr  Send Email to timsr     
Thanks everyone
pvonk posted 07-01-2005 04:05 PM ET (US)     Profile for pvonk  Send Email to pvonk     
I've recently installed a "cheap" Lowrance transducer/fishfinder and have the unit working. My question (since i also went through the decision-making process of transducer location on the stern) is how do I know if the transducer is too low in the water, wrong angle, etc.

My unit shows the lake bottom, depth, shows fish. If I don't have the unit properly located, what happens? Is the listed depth wrong? Is the graphic of the bottom false? Or is it obvious like lots of noise.

on a side note: When installing, I was careful to follow the installation manual when it came to the transducer angle. But once I was on the lake, it occurred to me that when the boat is moving slowly, it's angle with the water plane is very different then going at a moderate speed. Hence the angle of the transducer is never fixed, it's constantly changing due to the boat's pitch (I think "pitch" is the right word).

- Pierre

dcritch posted 07-02-2005 11:56 AM ET (US)     Profile for dcritch  Send Email to dcritch     
Timsr-You can see transducer location on "Tabasco" here: put mine on this side also. I may add a kicker and if I do I'm a little concerned about the impact on the transducer. I often load and unload at the beach and its been good to have a breakaway bracket.
Knot at Work posted 07-02-2005 12:46 PM ET (US)     Profile for Knot at Work  Send Email to Knot at Work     

hit a search on this topic, we have discussed it before. Some great info in past posts for you. Do the archives Search.

Who asked about the rotation direction? In Fwd the prop rotates clockwise.


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