Install transducer backwards for better reading?

[Junger]

This guy says the crystals are in the "front" of the transducer, so he installs it backwards for better reading. He says he gets scans at 40mph...that's impressive for a 3 in 1, non-high speed transducer. Anyone else install it this way?

 

 

[Bankc]

I've been thinking about this.  If the transducer being installed backwards allows it to bend under the force of the water when traveling at speed to angle better towards the rear, and this accounts for the better image, then I could understand how he might be getting better results.  And I could see this being the case, as most transducers have the joint at the front to prevent the flexing at speed.   

That being said, while you would get a picture, you wouldn't get an accurate one.  Your depth would be off, as it would show deeper water than what you're actually in.  And while you might get more detail, that detail would be skewed and unreliable.  Your transducer is now running at an angle.  

 

Then again, if the crystals are indeed in the front part of the transducer, and that's the source of the better readings, would you be able to go fast enough for this to have an effect, as the transducer isn't but a couple of inches long?  The speed of sound in freshwater is around 3,315mph.  So a sonar ping travels at around 4,861 feet per second, which means it only takes 0.016 seconds to scan the bottom in 40 feet of water.  At a speed of 40mph, or 58.7 ft/s, you travel 0.938 feet in 0.016 seconds, or 11.26 inches.  That is longer than the transducer.  So it seems at first that it could have an effect.  However, you have to take into account that the sonar ping acts as a cone, and not a straight line.  And at a 455kHz frequency, you're typically talking about something around a 16° cone.  In 40 feet of water, the cone size by the time the signal bounces back up to you is going to be around 22.9 feet wide.  Well take half that, because the front half of that cone doesn't matter since we're traveling forward, so we've still got 11.5 feet of cone to play with.  And that more than encompasses the 11.26 inches of the distance you passed at 40 mph.  

 

So, having done the rough math (which may be wrong), I'm inclined to believe that if there are any noticeable effects, they would be due to the first condition, that the transducer is being bent backwards by the force of the water, and that explains why he's getting better readings.  But, as noted, these readings will be unreliable, just like any readings when your transducer isn't level.    

 

[flyfisher]

1 hour ago, Bankc said:

I've been thinking about this.  If the transducer being installed backwards allows it to bend under the force of the water when traveling at speed to angle better towards the rear, and this accounts for the better image, then I could understand how he might be getting better results.  And I could see this being the case, as most transducers have the joint at the front to prevent the flexing at speed.   

That being said, while you would get a picture, you wouldn't get an accurate one.  Your depth would be off, as it would show deeper water than what you're actually in.  And while you might get more detail, that detail would be skewed and unreliable.  Your transducer is now running at an angle.  

 

Then again, if the crystals are indeed in the front part of the transducer, and that's the source of the better readings, would you be able to go fast enough for this to have an effect, as the transducer isn't but a couple of inches long?  The speed of sound in freshwater is around 3,315mph.  So a sonar ping travels at around 4,861 feet per second, which means it only takes 0.016 seconds to scan the bottom in 40 feet of water.  At a speed of 40mph, or 58.7 ft/s, you travel 0.938 feet in 0.016 seconds, or 11.26 inches.  That is longer than the transducer.  So it seems at first that it could have an effect.  However, you have to take into account that the sonar ping acts as a cone, and not a straight line.  And at a 455kHz frequency, you're typically talking about something around a 16° cone.  In 40 feet of water, the cone size by the time the signal bounces back up to you is going to be around 22.9 feet wide.  Well take half that, because the front half of that cone doesn't matter since we're traveling forward, so we've still got 11.5 feet of cone to play with.  And that more than encompasses the 11.26 inches of the distance you passed at 40 mph.  

 

So, having done the rough math (which may be wrong), I'm inclined to believe that if there are any noticeable effects, they would be due to the first condition, that the transducer is being bent backwards by the force of the water, and that explains why he's getting better readings.  But, as noted, these readings will be unreliable, just like any readings when your transducer isn't level.    

 

This is absolutely fantastic.....i was thinking of doing the same type of math to figure out the truth rather than what I think are better pictures and you saved me the hassle.

[Bankc]

1 hour ago, flyfisher said:

This is absolutely fantastic.....i was thinking of doing the same type of math to figure out the truth rather than what I think are better pictures and you saved me the hassle.

I'm at work, so I've got time.  

 

Though, I over-simplified it.  There's the angle of the boat's hull in the water that changes with speed to consider.  Plus the direction of the transducer's mount might affect its flow through the water and generate bubbles and mess with the readings.  And there are probably a hundred other variables I'm not mentally capable of considering.  Add all of that with the fact that I'm terrible at math these days (I was pretty good 20 years ago, but math is "use it or lose it", and I sure haven't used it).  So I'm not prepared to put any money on my conclusion.   

I also know that when mounting the transducer in the standard direction that you can lose the ability to pick up sonar at speeds above around 10 mph if you don't have it angled correctly.  Supposedly, you're supposed to angle it with about 3-5° of tilt so the back hangs lower than the front, and that should allow most transducer to work at higher speeds.  That's something I forgot about when doing my original post, and I don't remember exactly why that is.  But it could also explain this guy's results.  Perhaps someone else knows more about that. 

[MickD]

I get fine readings with my transducer installed as instructed by the manufacturer.  Yes it is critical to have the right height, but it gets readings at all speeds up to my boat's capability , which is about 33 MPH.  

 

I find it hard to believe that with the expertise and development resources that the makers have that simply installing a transducer backwards would make sense. 

[A-Jay]

33 minutes ago, MickD said:

I find it hard to believe that with the expertise and development resources that the makers have that simply installing a transducer backwards would make sense. 

Agreed ~

Also my desire to have an accurate 'sonar' reading at anything over clutch speed, is ZERO. 

For me the whole concept is like cutting a hole in the floor of my truck and

peering through it to see the pavement as I cruise down the road at 40 mph.   

Whatever I 'see' on the sonar unit is 300 feet behind me in just over 5 seconds. 

When is that helpful ?

Are we dropping waypoints on plane ?

I don't get it. 

YMMV

A-Jay 

[MickD]

10 minutes ago, A-Jay said:

Agreed ~

Also my desire to have an accurate 'sonar' reading at anything over clutch speed, is ZERO. 

For me the whole concept is like cutting a hole in the floor of my truck and

peering through it to see the pavement as I cruise down the road at 40 mph.   

Whatever I 'see' on the sonar unit is 300 feet behind me in just over 5 seconds. 

When is that helpful ?

Are we dropping waypoints on plane ?

I don't get it. 

YMMV

A-Jay 

Yes, A-Jay, you and I are geniuses.  🙂

 

[gim]

10 minutes ago, A-Jay said:

For me the whole concept is like cutting a hole in the floor of my truck and

peering through it to see the pavement as I cruise down the road at 40 mph.

I think you should do that on the new one that has been ordered. Or better yet, have it customized at the factory. 

[A-Jay]

8 minutes ago, MickD said:

Yes, A-Jay, you and I are geniuses.  🙂

 

If I give you my number,

would be kind enough to call here and tell my wife ? 

😎

A-Jay

[casts_by_fly]

56 minutes ago, A-Jay said:

Agreed ~

 

Are we dropping waypoints on plane ?

I don't get it. 

YMMV

A-Jay 

I like this thought. On a 12” solix it would be like an iPad game of whackamole. 

[MickD]

On 10/19/2023 at 6:40 PM, A-Jay said:

If I give you my number,

would be kind enough to call here and tell my wife ? 

if you will do the same. . . 

I like being able to read the depth at speed so that as the bottom starts to rise, I can slow down.  Yes, it would be too late for an obstacle like a log or rock, but still has value to keep track of the depth at speed. 

[Tennessee Boy]

Back in the days before GPS and detailed maps,  a Flasher that would work at higher speeds was critical for navigation.  Today I have no need for it.

[TnRiver46]

They’ve got buoys where I fish…….

[gim]

On 10/21/2023 at 11:35 AM, Tennessee Boy said:

Back in the days before GPS

People still use flashers here regularly in the winter for ice fishing (vexilar).

 

I haven’t been fishing as an adult long enough to have experienced navigation in a boat without modern GPS. We always had one in our boat when I was growing up. I would honestly be pretty blind without it. And I have no clue how to use a flasher either.

[Tennessee Boy]

13 hours ago, TnRiver46 said:

They’ve got buoys where I fish…….

I’ve never been able to remember which color is on the right and which color is on the left. 😆

[TnRiver46]

7 minutes ago, Tennessee Boy said:

I’ve never been able to remember which color is on the right and which color goes on the left. 😆

Just turn around and go the other way if you get it wrong hahahah

[Woody B]

I've got a few comments.

 

Like most everything on youtube I believe it's simply attention seeking behavior.   

 

Why didn't he have a video of the readings at speed included?

 

I see people all the time continually messing with their transducers to get a depth reading at speed.   What's the point?  It's certainly not good from a safety standpoint.  By the time the electronics and the person piloting the boat sees what on the screen they're way past it.   The person piloting the boat should be looking around the lake when going at speed instead of having their head buried in a screen.  

 

I get a depth reading up to ~20mph.   IMHO that's 10 mph faster than I "need" it.  

 

Added:  I'm thinking about mounting a transducer upside down so I can see the birds flying over.