Author Topic: My stainless steel DIY towfish.  (Read 14760 times)

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Offline Mappe

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My stainless steel DIY towfish.
« on: October 13, 2012, 03:23:01 AM »
My first home made towfish. Because im a sheet metal man, the only opinion was to build it from stainless steel. It weight 5,1 kilos. The pipe is 76mm and fins are laser cutted and TIG welded. Towfish head i turned from stainless steel. Cable is CAT6 and it goes inisde a rope.

Towfish, cable and unit.

Towfish
Sukellustyö Takala. Diving and geophysical survey service at Vaasa Finland.


Offline Rüdiger

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Re: My stainless steel DIY towfish.
« Reply #1 on: October 13, 2012, 08:08:03 AM »
Hello Neighbour

Congratulations. successful work. :)
Interesting is the cable routing over the nose of the fish.
How long is the pull cable and is it  patch-or installation cable?

mvh
Rüdiger

Offline Roddy

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Re: My stainless steel DIY towfish.
« Reply #2 on: October 13, 2012, 01:19:22 PM »
Mappe, Nice clean build! Very well done! Lets have some screen shots.

Roddy
Scan,Scan and Rescan Roddy

Offline Mappe

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Re: My stainless steel DIY towfish.
« Reply #3 on: October 13, 2012, 03:27:28 PM »
Hello Neighbour

Congratulations. successful work. :)
Interesting is the cable routing over the nose of the fish.
How long is the pull cable and is it  patch-or installation cable?

mvh
Rüdiger

Tack  Granne!

Cable is 28 meters long and its a CAT6 patch cable made for 500Mhz. It should be enough. I will post screenshots as soon as possible!
Sukellustyö Takala. Diving and geophysical survey service at Vaasa Finland.

Offline Rickard

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Re: My stainless steel DIY towfish.
« Reply #4 on: October 13, 2012, 04:49:51 PM »
Mappe,
nice fish! Please test it before the winter season and show us! Your neighbors expect snow within a week.. ;)
Rickard

Offline Mappe

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Re: My stainless steel DIY towfish.
« Reply #5 on: October 14, 2012, 10:13:25 AM »
First test drive with my towfish! The cable is actually 33m long. Towfish was 5-7m down from sea level when i scanned. Here are the screenshots. All taken 455khz.

Rocks... wondering why is temperature so high in this screen?
Sunken wood boat.
Sunken wood boat. (zoom)
Sukellustyö Takala. Diving and geophysical survey service at Vaasa Finland.

Offline Roddy

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Re: My stainless steel DIY towfish.
« Reply #6 on: October 14, 2012, 12:59:13 PM »
BINGO!!

Roddy
Scan,Scan and Rescan Roddy

Offline Rüdiger

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Re: My stainless steel DIY towfish.
« Reply #7 on: October 15, 2012, 03:22:00 AM »
Hi Mappe

Good pictures and that with the 455khz. :)
Update your unit, then you have the whole screen for the important things, without data window on the left side.

mvh
Rüdiger

Offline Mappe

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Re: My stainless steel DIY towfish.
« Reply #8 on: October 15, 2012, 03:33:22 AM »
Hi Mappe

Good pictures and that with the 455khz. :)
Update your unit, then you have the whole screen for the important things, without data window on the left side.

mvh
Rüdiger

Tackar!

How is the update made. Can you give me an easy instruction how to update my 898c si software? Thank you!
Sukellustyö Takala. Diving and geophysical survey service at Vaasa Finland.

Offline Rüdiger

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Re: My stainless steel DIY towfish.
« Reply #9 on: October 15, 2012, 04:23:43 AM »
Hi Mappe

Register your unit at HB support, then you get access to the latest firmware.
http://www.humminbird.com/Support/
Even here in the forum, you can download the latest firmware.
http://forums.sideimagingsoft.com/index.php?action=downloads;cat=20
Save the download to an SD card and put them into your unit. The new firmware is automatically detected and after two confirmation installed.
Attention! Concern for a stable power supply, a crash during the update is to be avoided at all costs.

mvh
Rüdiger

Offline Mappe

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Re: My stainless steel DIY towfish.
« Reply #10 on: October 16, 2012, 05:50:57 AM »
Hi Mappe

Register your unit at HB support, then you get access to the latest firmware.
http://www.humminbird.com/Support/
Even here in the forum, you can download the latest firmware.
http://forums.sideimagingsoft.com/index.php?action=downloads;cat=20
Save the download to an SD card and put them into your unit. The new firmware is automatically detected and after two confirmation installed.
Attention! Concern for a stable power supply, a crash during the update is to be avoided at all costs.

mvh
Rüdiger


I updated my firmware to v6.420 successfull.
Thanks for the instruction!
Sukellustyö Takala. Diving and geophysical survey service at Vaasa Finland.

Offline Kimi

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Re: My stainless steel DIY towfish.
« Reply #11 on: December 18, 2012, 03:38:45 PM »
Nice fish. Simple and beautiful.

wondering why is temperature so high in this screen?

One possibility is that seawater has come in contact whit the temperature sensor? The transducer is not built for highpressure in deepwater.
What happend after this "dive". Did the temp.readings go back to "normal"?

It can also has something to do whit the cable. (leaks, length?)

Greattings from south, terveisin etelästä. Kimi..
homepage: ( in Finish only) www.wreckdiving.yolasite.com

Offline Rüdiger

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Re: My stainless steel DIY towfish.
« Reply #12 on: December 19, 2012, 04:57:50 AM »
Hi neighbor ;)

This forum has already been reported that the cable inlet into the transducer is not pressurewater tight. >:(
Most resins shrink during curing and so the smallest leaks can arise.

mvh
Rüdiger

Offline Mappe

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Re: My stainless steel DIY towfish.
« Reply #13 on: December 22, 2012, 07:28:34 AM »
Hi neighbor ;)

This forum has already been reported that the cable inlet into the transducer is not pressurewater tight. >:(
Most resins shrink during curing and so the smallest leaks can arise.

mvh
Rüdiger

Tjena!

Thanks for the information. Ive allready sealed the cable inlet with a lot of sikaflex. :) I think it will work just fine!

Mappe
Sukellustyö Takala. Diving and geophysical survey service at Vaasa Finland.

Offline abraquelebout

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Re: My stainless steel DIY towfish.
« Reply #14 on: December 22, 2012, 10:52:17 AM »
hi
if the water came into the cable you must have this pictureila_rendered
lot of gosht and noise, i want to find the best solution,  connecting box full of resins ?

Offline Kimi

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Re: My stainless steel DIY towfish.
« Reply #15 on: December 22, 2012, 12:15:36 PM »
if the water came into the cable you must have this picture lot of ghost and noise,

This is of course one possibility. But I think that the main reason of "ghostechoes" is that if the transducer got a clear and loud signal from one direction , but nothing from the opposite direction, it will "hear" the same returnsignal with the both piazoelements. Its good to remember that we are talking about a acoustic signal. The piezoelement does not understand from what direction the sound is coming.

An other thing that would be interesting to know and understand is what is really happening in a towfisch. Especially if it is made of metal.
Does the body(metaltube) collect the signal or and reflect it back. And what are the fins doing? Are they acting as somekinds of acoustic reflectors.

I have several times seen that the picture quality varies from good to poor, when I have using my own towfish. Towing the same route and same depth. So I guess that there is something happening down there that I don't understand. Maybe the fish i shaking, or maybe there are some acoustic resonance in the fish body?

Do someone got any ideas??

Kimi..
homepage: ( in Finish only) www.wreckdiving.yolasite.com

Offline abraquelebout

  • volunteer rescue diver, surfer, publicist, submarine archaeology
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Re: My stainless steel DIY towfish.
« Reply #16 on: December 22, 2012, 01:49:40 PM »
for my experience , it's the second gosht sequence i see, in the 2  when i cut the cable, the salt water make Electrolysis in some wire and ground, verry bad !!
for steel or metal remember what append to Jolly Roger :
http://forums.sideimagingsoft.com/index.php?topic=1753.0

Offline Mappe

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  • Accessories: Towfish + 30m cable
Re: My stainless steel DIY towfish.
« Reply #17 on: December 22, 2012, 05:10:01 PM »
Nice fish. Simple and beautiful.

wondering why is temperature so high in this screen?

One possibility is that seawater has come in contact whit the temperature sensor? The transducer is not built for highpressure in deepwater.
What happend after this "dive". Did the temp.readings go back to "normal"?

It can also has something to do whit the cable. (leaks, length?)

Greattings from south, terveisin etelästä. Kimi..

Towfish has worked just fine and the information on screen is correct.
Greetings from Vaasa... Ice 30cm at sea and very cold.
Terveiset Vaasasta... Jäätä 30cm ja pirun kylmä.
Sukellustyö Takala. Diving and geophysical survey service at Vaasa Finland.

Offline Rüdiger

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Re: My stainless steel DIY towfish.
« Reply #18 on: December 23, 2012, 04:36:11 AM »
I have several times seen that the picture quality varies from good to poor, when I have using my own towfish. Towing the same route and same depth. So I guess that there is something happening down there that I don't understand. Maybe the fish i shaking, or maybe there are some acoustic resonance in the fish body?

Hi Kimi

Could be that the water temperature has influence on acoustic reflections, and thus the image quality.

mvh
Rüdiger


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