Fish Finder That reads while driving ?

[bruceb58]

Re: Fish Finder That reads while driving ?

Not to get too technical here, but you can out drive the transducer signal depending on the depth of the water and speed.

Speed of sound in water is 4700 feet/s. At 30MPH you are going 44 feet/s. I don' think its going to be an issue.

Basically, you can't out drive it.

 

[UncleWillie]

Re: Fish Finder That reads while driving ?

My sonar read the depth just fine at 50+ mph. Even the side scan gives a picture, and that is about as narrow a beam as you will find.

We would like to see another picture of the bottom area in front of the Transducer.
We need to see the big picture, so not to close up.

Unless it is a clean shot to the bow, the sonar is going to have issues.
That step is not something to be discounted. As you have already seen, It is a major obstacle.
Any replacement transducer is going to have exactly the same problem.

 

[dingbat]

Re: Fish Finder That reads while driving ?

Not to get too technical here, but you can out drive the transducer signal depending on the depth of the water and speed.

Yes and no....sound travels at roughly 4,900 ft. per second in water. It would take 0.0040 seconds for the signal to travel to the bottom and back in 20 ft of water.

At 60 mph, your traveling at 88 ft. per second. So.....you would move 88' x 0.004 seconds = 4.2" of travel in-between bottom returns. Returns from objects in the water column would return much quicker. Since holding bottom typically isn't the problem, the speed of the signal and boat isn't the problem.

At issue is the units sampling and processing rate (PRR) and the speed/quality (Q value) of the transducer. The importance of these two parameters can't be understated yet find a rating/specification for either in the big box sonar literature.....

The PRR is the number of times the units "pings" in a minute. Most BB sounders max out or fixed at 1500 PRR. At 1500 PRR your sampling once every 0.04 seconds. That is 10 times slower than the bottom returns from 20'. Now your looking at an update every 42". Not to mention, your not sampling fast enough to see anything in the water column.

Your better sounders run 3000 PRR and adjust the ping rate by depth, giving much improved shallow water performance

 

[bruceb58]

Re: Fish Finder That reads while driving ?

At 60 mph, your traveling at 88 ft. per second. So.....you would move 88' x 0.004 seconds = 4.2" of travel in-between bottom returns.

Actually, you travel 88' x 0.004 = 0.352 feet from the TX of the ping to the Rx of the ping. At 1500 PRR, you would travel 88' x 0.04 = 3.52' between the pings.

 

[yzf125]

Re: Fish Finder That reads while driving ?

Ok here are a few more pics.

 

[bruceb58]

Re: Fish Finder That reads while driving ?

Looks like your transducer isn't in the water when you get up on plane. It's a little deceiving since the back of the boat is offset from where the V of your hull stops. Basically, You need to move it away from that bunk so you can drop it so the complete bottom surface of the transducer is below the water.

 

[yzf125]

Re: Fish Finder That reads while driving ?

So you suggest that I lower it from its location now ? and by how much ?

Thanks

 

[bruceb58]

Re: Fish Finder That reads while driving ?

You need to put a straight edge along the bottom of your hull back to the transducer on the left edge of it. The transducer needs to be lower than the edge of the straight edge. Looks like your trailer bunk is preventing you from lowering it more.

 

[UncleWillie]

Re: Fish Finder That reads while driving ?

The transducer will need do be Below the Step in the hull.
As the Bunk is supporting the Step and a Strake, that means the Transducer will need to be lower than the top of the bunk. This looks to be 2-3 inches. I do not think you will be able to lower it that far using the current bracket.



Option #2 is to move the transducer over to the Starboard side, to a point outside of where the Step/Strake ends. This may be fairly close to the Tie down strap.

 

[dingbat]

Re: Fish Finder That reads while driving ?

Moving transducers out towards the chine rarly if ever produces satisfactory results.

You really only have two options if you want more than marginal performance. Move it down to the "pocket" or turn it into a shoot thru installation.

If all you care about is seeing bottom, I would go to a shoot thru installation and be done with it

 

[yzf125]

Re: Fish Finder That reads while driving ?

Just what does that mean ? ""a shoot thru installation""

 

[mrmamiller]

Re: Fish Finder That reads while driving ?

From the recent pics, looks like maybe the step in the hull could be an issue. Another thing to try: IF your hull bottom has no fillers of any kind or air pockets, you might want to try shooting through the hull forward of the step. Find a spot in the bilge where you know there is nothing directly below it to create any turbulence, then take a margarine tub, cut out the bottom, and stick it to the inside of the bilge floor. When your sealant is dry, fill the tub with water and sit the transducer in the tub of water so that the face of the transducer is facing straight down. Not much work if you have easy access to a spot in the bilge forward of the step. This should work.

 

[midcarolina]

Re: Fish Finder That reads while driving ?

Moving transducers out towards the chine rarly if ever produces satisfactory results.

You really only have two options if you want more than marginal performance. Move it down to the "pocket" or turn it into a shoot thru installation.

If all you care about is seeing bottom, I would go to a shoot thru installation and be done with it

I agree....Is the Lowe boat in your sig the boat in question? If shoot thru is not attractive to you, I would talk to other owners of your model boat and see where others that have that model boat have theirs mounted...

That way you dont have a bunch of holes to fill..........