transducer angle

Huntindave thanks for the better explanation. would it be true to say tilting the cone will create a larger dead zone?

[Huntindave]

Originally Posted by 2004 Lund Pro V Tiller

Huntindave thanks for the better explanation. would it be true to say tilting the cone will create a larger dead zone?

Yes that would be an accurate conclusion.

ONE THING TO NOTE; Clawman said "thru hull transducer" so my comments are on the assumption he is talking about traditional 2D sonar. Side imaging and down imagining use multiple beams and different logarithms to analyze the data. I don't believe those can shoot thru the hull, but I could be mistaken on that.

[TomP.]

On many hulls running at speed the 2D backend needs to be tilted a little down some to take up the difference of angle when the hull is on plane or just sitting to get good high speed readings.

[reddog]

Originally Posted by Huntindave

Yes that would be an accurate conclusion.

ONE THING TO NOTE; Clawman said "thru hull transducer" so my comments are on the assumption he is talking about traditional 2D sonar. Side imaging and down imagining use multiple beams and different logarithms to analyze the data. I don't believe those can shoot thru the hull, but I could be mistaken on that.

Down imaging can indeed work in a shoot thru application, but very few utilize it, or even know it can. In my opinion, DI is the best performer at speed.

Excellent explanation Dave, and you are correct, that you will be increasing the dead zone area, and limiting the time your transducer will see the target by installing not parallel to the bottom.(+- a few degree so).

DI does not carry the same limitations, in regards to the dead zone. Here's a screen capture that kind of shows .

[Gary Korsgaden]

Vexilar Edge units, ahead of their time with dual transducers one wider then the other. The narrower cone angle less dead band but less coverage, wide cone angle more coverage area increased dead band. With both transducers one narrow and one wide of different frequencies to prevent interference. Really helps pinpoint fish or certain points on a structure. Wide to show coverage and narrow to pinpoint. The Vexilar Edge is one unit for the fore-mentioned reasons I will not part with

Tilting a transducer, have for years with a flasher now a LCD. My application is on the bow trolling motor using the width of a small screw head under the back or stern sideducer to tilt forward slightly. This small angle forward, when the troll motor goes side to side shows me the slope of a drop sharp or gradual.

Not sure this adds much of answer to your question just thought I would share anyway

[clawman]

Originally Posted by Gary Korsgaden

Vexilar Edge units, ahead of their time with dual transducers one wider then the other. The narrower cone angle less dead band but less coverage, wide cone angle more coverage area increased dead band. With both transducers one narrow and one wide of different frequencies to prevent interference. Really helps pinpoint fish or certain points on a structure. Wide to show coverage and narrow to pinpoint. The Vexilar Edge is one unit for the fore-mentioned reasons I will not part with

Tilting a transducer, have for years with a flasher now a LCD. My application is on the bow trolling motor using the width of a small screw head under the back or stern sideducer to tilt forward slightly. This small angle forward, when the troll motor goes side to side shows me the slope of a drop sharp or gradual.

Not sure this adds much of answer to your question just thought I would share anyway

The underlined sentence is precisely why I asked the question. I am not looking at a great angle forward just 5deg.

Before transducers were part of a trolling motor head it was not uncommon to mount the transducer a slight bit to the port side. That way when you marked something you could turn the trolling motor left or right in an attempt to determine exactly where the object is.
Back to the subject at hand, when you are vertical jigging and see an object if you are already directly over it it may be too late to fish it.

[Gary Korsgaden]

Originally Posted by clawman

The underlined sentence is precisely why I asked the question. I am not looking at a great angle forward just 5deg.

Before transducers were part of a trolling motor head it was not uncommon to mount the transducer a slight bit to the port side. That way when you marked something you could turn the trolling motor left or right in an attempt to determine exactly where the object is.


Back to the subject at hand, when you are vertical jigging and see an object if you are already directly over it it may be too late to fish it.

I prefer a wide angle transducer and narrow one for vertical jigging, one to scan and locate the other to pinpoint for the presentation. 5 degree tilt forward sounds right, I have just used the head of a medium screw. thanks

[Huntindave]

Originally Posted by Gary Korsgaden

My application is on the bow trolling motor using the width of a small screw head under the back or stern sideducer to tilt forward slightly. This small angle forward, when the troll motor goes side to side shows me the slope of a drop sharp or gradual.

Originally Posted by clawman

The underlined sentence is precisely why I asked the question.

You understand that this works because Gary is "sweeping" the transducer?

Your original question was in regards to a thru hull transducer. Are you planning to sweep your boat hull side to side to achieve the desired results?

[LWinches]

Several issues have been brought up since you asked the question. I have had different experiences with this than some. For years I have used tilted transducers, but mounted on the trolling motor, not in the bilge. I also have extensively used tilted transducers on the transom, tilted to the left and right. Yes, you get a larger dead spot near the bottom. Also there are issues that arre brand related. As far as I can tell, the current algorithms for sonar for all brands is to first determine the depth. Tilting the transducer can affect the units ability to establish a depth. The ping rate is determined after the depth is determined. This is often true even if you have a manual setting for the ping rate. Sometimes the ping rate setting is interpretted as a suggestion to the software, instead of an actual mandatory setting. If the depth cannot be determined, your sonar may not function. Of the three, Hbird, Lowrance and Garmin, Garmin tolerates tilting better than the others, meaning you can tilt it more without losing operation.

There also seems to be an internal threshold number that is not user adjustable, for determining whether or not to display a return. I also see this in what's called A-Scope, or Real Time Sonar, that seems to imply that the raw returns are displayed real time. My experience is that a return must occur repetitiously, for this threshold number of times, before it will be displayed. I say this because there seems to be a disparity between the pure math of sonar returns at speed and what is shown on screen.

[Schins]

Humminbird used to have inexpensive portable units that had 2d shooting horizontally to see fish. (i.e. 120 Fishin Buddy)
How did they pull this off without seeing a "bottom"?