Yellowfin Sidescan Sonar

[willi1818]

Hi
the new Imagenex Yellowfin Sidescan Sonar seems interesting (a big Sportscan)
Does anybody here know what its price is or any other useful info.
Thanks

[ST krischan]

Re: Yellowfin Sidescan Sonar

hi,

the yellowfin costs about 12000 canadian dollars
and is available at sharkmarine.com or roperresources.com

[deepseawater]

yellowfin

we had problem how to establish the yellowfin (tow fish) fly trough in the water if the tow fish under tow on the speed is below 2 knots and fact is the fish will fly below water surface. So far we have to use bracket to hold and get the fih establish.

please give me some suggestion for this matter.

[Gonyo]

The trick is extra wings

Hi yellowfin,

the trick is to use selfdesigned wings. There are three possibilties:
1.) attach a V-wing to the top and use the holes already there for the cable to attach the wing
2.) drill holes in the top fin of the tailsection (where NO transducers are in) and attach a wing there - this is better than 1. because the wing will work at the end of the fish better than on the front
3.) make a new middlesection that is longer than the one coming with the fish - therefore you will need a lathe to build it the same way at the original.

I use 1.) and it is working fine for me - if you send me your email adress I can send you some pics.

Cheers

Gonyo

[Clart]

Yellowfin stability

I'm also having trouble getting the Yellowfin to stabilise and to get to depth. Are you able to post any pictures of your modifications?

[Gonyo]

Wing Layout

Hi,

I made the wings just on the fly - they work great and my new 7kg head out of my lathe filled with lead even better

[Clart]

Thanks for the picture.

What is the total weight of your fish now? I noticed that the standard weight is 5kg (I do add about 17lbs to this) wherease the Edgetech fish I'm used to using is 25kg. Kind of explains why I can't get it to sink deeper than 20m even at 1.5kts!

[Unregistered]

Does anyone have any images of Yellowfin sonar data? My looks pretty bad but the fish is not flying straight or sinking well.

[Gonyo]

Yellowfin scan

Hi,

this is a sail of a surfboard in 6m depth in the Ammersee near Munich. The long line is a rope on the ground.
In the beginning I had big problems with the yellowfin - pitch, yaw everything... with the right wing and a heavy head its not longer a problem.
The maximum depth I scanned was 80m with approx. 140m cable out.

[Clart]

Thanks! That is a very interesting image. Which frequency were you using?

[Clart]

The thing that I notice about the Yellowfin data is the low resolution. I think that is the correct word. I mean the number of pixels looks small so the image appears 'blocky' compared with some other sonars.

[Gonyo]

Yellowfin low resolution

Hi,

yes, you can see the low resolution - other sidescan programms (except the Kleins ) just put something like a blur effect over it and it looks better. When you look at the opening angle of most sidescans the resolution is really poor but the pictures look fine. I made the same scan with my humminbird 987 and the pictures look a lot better



But they are just more blurry than the other one because the resolution is worse. The human eye does the rest.

[Clart]

"When you look at the opening angle of most sidescans the resolution is really poor but the pictures look fine."

What do you mean by opening angle?

"But they are just more blurry than the other one because the resolution is worse. The human eye does the rest."

And I'm not sure I understand. Are you saying the the Hummingbird has a worse resolution but the human eyes intrepets the blurred data as clearer?

I'd much prefer the hummingbird data to the yellowfin.

[Gonyo]

Blurry

Hi Clart,

the opening angle is the horizontal beam width - the ping starts at the transducer very narrow (Klein has only 0.35 degrees) but because the degree is bigger than 0 the beam becomes wider and wider when it starts to travel away from the transducer. So at the beginning you really slice like a laser beam through the water but when you are some meters away you have 10cm beamwidth then after 50m already 1m etc. So you cannot see objects clearly when the beamwidth is to wide from a certain distance on.
Thats why the pictures are much clearer when object apear near the transducer.

When the beam comes back to the transducer the signal is processed and then displayed (nowadays) by software. You can programm the software the way you like - so if you want to show a better picture you interpolate between the pixels so you get a higher resolution on the monitor but the signal from the sidescan stays the same.

The humminbird looks better but normally the length of the transducer gives you a hint on the horizontal beamwidth - the fact that you won´t get the information from humminbird shows to me that the beamwidth must be very poor! Imagenex gives you:

260 kHz: 2.2o
330 kHz: 1.8o
770 kHz: 0.7o

Humming bird gives you:

HD Side ImagingSonar Coverage

• 455 kHz / (2) 86˚ @ -10db
• 800 kHz / (2) 55˚ @ -10db

So no info means poor specs!
But I love my humminbird too - it is very easy to deploy and works fine for shallow water - I found a wreck (7m length) in 54m depth with the humminbird - but only because there was nothing else there

Cheers

Gonyo

[Clart]

So what is it about the probably lower spec'd Hummingbird that makes it better than the Yellowfin?