Author Topic: DYI towfish Mminnesota  (Read 18756 times)

0 Members and 1 Guest are viewing this topic.

Offline danl

  • Newbie
  • *
  • Joined: Feb 2012
  • Posts: 13
DYI towfish Mminnesota
« on: February 15, 2012, 08:32:36 AM »
Following the great information in this forum, I built a towfish for using with a Lowrance HDS10 sidescan.
Drawing and picture attached.
To be used with 60ft (appr. 20m) of cable for shallow use (20-30ft ( appr. 7-10m)) in freshwater lakes at low towing speeds.  We are a sheriff dept. dive team and no experience yet with our own sidescan, so this will be a first towfish for testing.  Main use will be looking for vehicles and victims.
Plan to pull the fish from a short boom off the front of the boat (20ft, 150hp outboard), use a separate battery and coil the cable in a figure 8.
Please add any suggestions/advice/additional information that would help.
The towfish is 2" PVC tubing, 6lbs (2.7kg) nose weight, 40"(102cm) long.  Towing point and transducer mounting slide fore/aft for balancing.  Current balance point is about 1/3 from nose. Total cost less than $50.
Lakes are frozen now, we probably can't test until April.
« Last Edit: February 15, 2012, 08:35:15 AM by danl »


Offline Roddy

  • Hero Member
  • *****
  • Joined: Feb 2011
  • location: Mount Pleasant,Charleston Co,SC. USA
  • Posts: 607
  • Scan,scan and rescan
  • Unit(s): 797c2, 947c,987SI/DI,570di,1198,1155,Ip
  • Accessories: wx/Tow Fish,Drop Cam's,ROV''s
Re: DYI towfish Mminnesota
« Reply #1 on: February 15, 2012, 11:13:19 AM »
Dan, Cool! You might add more weigh to the nose 5 to 10 kg. What are you using as a com cable? Never try ed tow off the bow?

Nice fish, seen one somewhere?

Good luck and good hunting.

Roddy
Scan,Scan and Rescan Roddy

Offline Rüdiger

  • Sr. Member
  • ****
  • Joined: Feb 2011
  • location: Hjältevad Sweden
  • Posts: 427
  • He who seeks finds
  • Unit(s): 898 CX SI ;EAGLE 500CDF
  • Software: DrDepth BT+SS
  • Accessories: Towfish and Towcam
Re: DYI towfish Mminnesota
« Reply #2 on: February 16, 2012, 01:37:18 AM »
Hi Danl

 Grattulation, a successful Towfish. :)
 Do you use the StructureScan transducher?
 Are eagerly awaiting the first test results.

mvh
Rüdiger
Sorry
English is not my first language !
http://de.groups.yahoo.com/group/SOB-International/

Offline Drifter

  • Shade Tree Mechanic
  • Jr. Member
  • **
  • Joined: Jun 2009
  • location: Just around the Bend ~~~ Florida
  • Posts: 72
    • Limbatus.Net Info
  • Unit(s): 737 / 798ci SI / 997c SI / HBPC
  • Software: 4960/6300/6300/4.3.3
  • Accessories: Razorfish (3) ~ WeatherSense
Re: Plan to pull the fish from a short boom off the front of the boat
« Reply #3 on: February 16, 2012, 04:41:42 AM »
danl,

I've done a good bit of towfishing in the 20 to 30 foot range (saltwater) using a short tether. I can occasionally get away with towing from the bow, but bow movement in anything other than flat calm conditions resulted in the towfish "porpoising". My current towfish all have the transducers mounted towards the front. I plan on trying a rear mounted transducer this spring to see how much difference it can make. A longer tether with a shallow running towfish could help stabilize the towfish, but you'll probably need to tow from the stern to keep the cable free of the prop. A heavily weighted towfish can be deployed about a third of the way down the hull (and still run ahead of the prop) if it has a low enough drag profile.

  • Please tell us about your cable and connections.
  • Do you know if the Lowrance Sonar Log Viewer (or any third party software) can replay the Structure Scan recordings?
  • Does Lowrance have an emulator for the HDS 10 (Gen2?) / LSS-1 unit?

Thanks,
Darrell


(Edit: morning => afternoon grammar)
« Last Edit: February 16, 2012, 04:48:04 AM by Drifter »

Offline danl

  • Newbie
  • *
  • Joined: Feb 2012
  • Posts: 13
Re: DYI towfish Mminnesota
« Reply #4 on: February 16, 2012, 07:20:48 AM »
I really don't know anything yet about the sidescan equipment.  I just built the towfish.  On Saturday, I meet the guy who knows the electronics, cable info, etc.  I will try to get answers to yor questions.
Bow towing does seem a problem for shallow running and a shallow running angle on the cable potentially hitting the prop.  So off the stern it is....
Location of the transducer to me seems best centered right below the tow point, the center of any pitch or yaw rotation. See the diagram (two transducers in different locations shown).....any change in pitch changes the position of the  transducer more as it is farther away from the cable attachment.
So change in depth from porpoising can't be corrected for, but change in pitch or yaw from porpoising might be minimized by centering the transducer under the tow point.  Just assumptions...is that how it might work???
« Last Edit: February 16, 2012, 07:23:17 AM by danl »

Offline sonar2000

  • Chief
  • Global Moderator
  • *
  • Joined: May 2009
  • location: Kerr Lake NC
  • Posts: 5970
  • It is not lost ...it has been misplaced.
  • Unit(s): (1) 1197 (1) 1198
  • Software: 6.6
  • Accessories: Tow Fish
Re: DYI towfish Mminnesota
« Reply #5 on: February 16, 2012, 07:24:01 AM »
Just curious, but......if you are in shallow water why the towfish..  Or does lowrance structure scan work differently than side imaging from HB?
Most of the side looking surface mounted transducers work well to a depth of 30 feet for SAR purposes.

Just kind of curious...

(edit)  I forgot to mention that this is a nice looking towfish.... ;D
Chuck
« Last Edit: February 16, 2012, 07:34:08 AM by sonar2000 »

Offline danl

  • Newbie
  • *
  • Joined: Feb 2012
  • Posts: 13
Re: DYI towfish Mminnesota
« Reply #6 on: February 16, 2012, 07:59:58 AM »
Sonar 2000,
Thanks...
I'm a total rookie at all this, but I understand that much of the search activity could be in the range of 20-30 ft, but the lakes here can also go deep, so depth in the range of 100 ft is possible.
The question I asked was why we have only 60ft of cable.  Seems we would need maybe triple that to cover the deeper lake areas.
Roughly how far down can side scan look?  Is there an approximate "best distance from bottom" for general search sweeps for SAR work?  Is there a good "sidescan 101" article somewhere out there?
Thanks much,
Dan

Offline sonar2000

  • Chief
  • Global Moderator
  • *
  • Joined: May 2009
  • location: Kerr Lake NC
  • Posts: 5970
  • It is not lost ...it has been misplaced.
  • Unit(s): (1) 1197 (1) 1198
  • Software: 6.6
  • Accessories: Tow Fish
Re: DYI towfish Mminnesota
« Reply #7 on: February 16, 2012, 08:34:44 AM »
I think if you go to the Search and Rescue section of this forum there are some good postings on your needs..
http://forums.sideimagingsoft.com/index.php?topic=672.0
We have lakes that vary in depths like you and generally run the surface mount to depths of 40 feet. Over that we go with the tow fish.
Of course we have several boats and units.
General rule of thumb for the HB and Lowrance units is (for sar) to keep the transducer beam no more than 40 feet from the bottom and no more than 50 feet each side.
sometimes using only one side of the two beam transducer will help in the display.
In reality most of our scans are reviewed on an external viewer as you have more time to look at a target.
Depending on the bottom of the lake/river and what else is there, the target of interest is not the shape that you might be thinking..
The closer you can get the transducer to the target the better image you will get..within in reason..
Also sonar will power up right from the box.  It is the boat operator and the sonar operator that produce result. This takes base learning, a lot of time and experience. Most sonar training lets you learn what is normal and then you look for the abnormal or unusual..
One important thing to remember about running sonar is what you say at the end of the search..for sonar to run the scan, say we did not see a target and then have the target float on its own..is not what we should be doing..
We can be more precise than that..

Chuck
« Last Edit: February 16, 2012, 10:04:25 AM by sonar2000 »

Offline danl

  • Newbie
  • *
  • Joined: Feb 2012
  • Posts: 13
Re: DYI towfish Mminnesota
« Reply #8 on: February 16, 2012, 09:34:59 AM »
Chuck.
Thanks for the link and the advice.  Much appreciated.
Anxious for the ice to go out this spring so we can start playing with the new toy...
What are some good things to use as practice targets?

Offline sonar2000

  • Chief
  • Global Moderator
  • *
  • Joined: May 2009
  • location: Kerr Lake NC
  • Posts: 5970
  • It is not lost ...it has been misplaced.
  • Unit(s): (1) 1197 (1) 1198
  • Software: 6.6
  • Accessories: Tow Fish
Re: DYI towfish Mminnesota
« Reply #9 on: February 16, 2012, 10:09:57 AM »
Run scans on normal lake botttoms so you can get used to what is there. Ask fishermen to look at your scans, they are already pretty well clued to the bottom. Or even go out with them and have them show you their units...
You can place objects such as blocks, drums or other items.  If you do that then mark them with a surface attached float so you know where and what each is..
For victim simulation you can use a dead pig or deer or dog.. (yuck) but it works.

Chuck

Offline danl

  • Newbie
  • *
  • Joined: Feb 2012
  • Posts: 13
Re: DYI towfish Mminnesota
« Reply #10 on: February 16, 2012, 10:17:25 AM »
Chuck,
Great.  As I learn more and we go forward, I'll keep you posted and look forward to your greart feedback.
Thanks,
Dan

Offline sonar2000

  • Chief
  • Global Moderator
  • *
  • Joined: May 2009
  • location: Kerr Lake NC
  • Posts: 5970
  • It is not lost ...it has been misplaced.
  • Unit(s): (1) 1197 (1) 1198
  • Software: 6.6
  • Accessories: Tow Fish
Re: DYI towfish Mminnesota
« Reply #11 on: February 16, 2012, 10:22:58 AM »
Dan, check my profile and at anytime email or call if you want to chat. If your long distance phone for a call is a charge, then send me you number and a time to call...Mine are free...

Chuck

Offline danl

  • Newbie
  • *
  • Joined: Feb 2012
  • Posts: 13
Re: DYI towfish Mminnesota
« Reply #12 on: April 28, 2012, 06:27:21 AM »
Finally tested the towfish in the water.  Please review results and attached drawing and provide advice.
The fish, with transducer attached, was towed behind the boat from the port quarter. The tow attachment point on the fish was adjusted fore/aft to make the fish exactly horizontal in water.  Only 50ft (15m) of cable actually in-water was available.  Boat speed was 3mph (4.8kph).
With 50ft of cable let out, the fish was visible at its maximum depth of 15ft (4.6m).  It was horizontal and very stable.  There was no "porpoising", etc. 
We are still rookies with the sonar interpretation, but the bottom signal looked very clear and had very good definition.  We were able to clearly see a box, 18" x 18" (46cm x 46cm) with rocks in it at 50ft (15m) depth. The fish tracked very well with the boat on a straight path.  On turns, there was the expected offset of the fish track from that of the boat.
The key questions that arise:
1. We can only get to 15ft with the current setup.  How to get deeper (to 80ft (25m))?
        -  More weight?  Is the fish too light at 12lbs (5.5kg)?
        - More cable is needed.  Is the tow ratio observed (line length to depth) of 3.3 a typical ratio?
        - What are your fish weight/line length/depth/tow speed data for comparison?
2. New, longer cable questions:
         -  Does anyone have specific source, cost and ordering info for Cat7 or Cat8 cable so we can get a longer
             one-piece cable?   The current cable is three 20ft sections plugged together.
         -  Same question for waterproof connectors: specification, source, cost?
3. Does a simple "downrigger" (lead ball with a fin) or this downrigger:
                   http://www.fish307.com/pro-trollhighspeedplaner.aspx
             work as well as a tubular finned fish? 

Thanks for any feedback.
DanL

« Last Edit: April 28, 2012, 06:39:52 AM by danl »

Offline Rüdiger

  • Sr. Member
  • ****
  • Joined: Feb 2011
  • location: Hjältevad Sweden
  • Posts: 427
  • He who seeks finds
  • Unit(s): 898 CX SI ;EAGLE 500CDF
  • Software: DrDepth BT+SS
  • Accessories: Towfish and Towcam
Re: DYI towfish Mminnesota
« Reply #13 on: April 28, 2012, 08:21:45 AM »
Hi Dan

A downrigger is very beneficial to bring the fish to depth, but means an extra stress for the tow cable.

mvh
Rüdiger
Sorry
English is not my first language !
http://de.groups.yahoo.com/group/SOB-International/

Offline satburn

  • Newbie
  • *
  • Joined: Apr 2012
  • Posts: 4
Re: DYI towfish Mminnesota
« Reply #14 on: April 28, 2012, 08:29:21 AM »
3. Does a simple "downrigger" (lead ball with a fin) or this downrigger:
                   http://www.fish307.com/pro-trollhighspeedplaner.aspx
             work as well as a tubular finned fish? 


I am new to this as well but i will be testing mine with a downrigger next week and i will let you know about the results (boat speed - depth)
The attached photo is the downrigger weight i will be using (6.5kg)
The shape helps it to dive deeper than an ordinary downrigger lead ball
The cable that i will use is this..
http://export.rsdelivers.com/product/alpha-wire/6076c-sl005/6-pair-individually-shielded-cable-30m/1119212.aspx

nice work on the towfish!

@Rüdiger
The downrigger weight will not be supported by the cable

« Last Edit: April 28, 2012, 08:37:26 AM by satburn »

Offline Rüdiger

  • Sr. Member
  • ****
  • Joined: Feb 2011
  • location: Hjältevad Sweden
  • Posts: 427
  • He who seeks finds
  • Unit(s): 898 CX SI ;EAGLE 500CDF
  • Software: DrDepth BT+SS
  • Accessories: Towfish and Towcam
Re: DYI towfish Mminnesota
« Reply #15 on: April 29, 2012, 12:06:32 AM »
Hi Sat

I am not speaking of weight :(, I am speaking about the water resistance.

mvh
Rüdiger
Sorry
English is not my first language !
http://de.groups.yahoo.com/group/SOB-International/

Offline danl

  • Newbie
  • *
  • Joined: Feb 2012
  • Posts: 13
Re: DYI towfish Mminnesota
« Reply #16 on: May 11, 2012, 06:51:32 AM »
The PVC towfish test went well.  We could clearly see the towfish at 15ft and at speeds from 2 to 4mph, it was very stable and after a minor trim adjustment was also very stable horizontally.  The fish was not heavy enough, so a new one will be built using 2.5" galvanized pipe for the body.  It will have an internal 2" pipe that can slide fore/aft to trim the pitch of the towfish.  We seem to have a very workable towfish design.  Now we need some mod's to the sonar setup.
 Attached pics show a towfish design and proposed sonar system.  We need to do bottom searches ranging from very shallow to over 100ft in northern Minnesota lakes. Our current hull mounted transducer doesn't give us the definition we need to find our targets. In prelim tests we've done, towing a transducer at 15ft gave us much better results. We would like to extend the depth of the towfish to about 40-50ft to improve results for 100ft-plus bottom searches.
The towfish design has been built and tested and provides a stable platform for the transducer.
The big question is whether the proposed sonar setup with longer cable and transducer switch will work well. The design shown is with a Lowrance HDS10/StructureScan sonar. ( I realize this is a Humminbird forum, and don't want to hijack the forum, but Lowrance provides no useable technical help and ther is no comparable web source of Lowrance info that I could find.)
Will the 150ft Cat6 cable work?  With the two-transducer switch and 150ft Cat6 cable, are any special cable terminations (impedence matching, etc) needed?   I plan to stagger cut the Cat 6 wire pairs, do soldered splices, re-twist the pairs, and replace insulation and shielding. The towline will be a small diameter low/no stretch synthetic rope.  Any recommendation on best towline material (Kevlar, Dyneema, polyester, etc) would also be very helpful.
Any advice, sources for additional info or help would be appreciated. Thanks very much.
DanL
« Last Edit: May 11, 2012, 06:52:33 AM by danl »

Offline Rüdiger

  • Sr. Member
  • ****
  • Joined: Feb 2011
  • location: Hjältevad Sweden
  • Posts: 427
  • He who seeks finds
  • Unit(s): 898 CX SI ;EAGLE 500CDF
  • Software: DrDepth BT+SS
  • Accessories: Towfish and Towcam
Re: DYI towfish Mminnesota
« Reply #17 on: May 11, 2012, 07:29:41 AM »
Hi Danl

Interesting approach to trim by internal weight shift. :)
The true theme here cable already been dealt with, look here for, because you can find many information about it.

 http://forums.sideimagingsoft.com/index.php?board=41.0

mvh
Rüdiger
Sorry
English is not my first language !
http://de.groups.yahoo.com/group/SOB-International/

Offline danl

  • Newbie
  • *
  • Joined: Feb 2012
  • Posts: 13
Re: DYI towfish Mminnesota
« Reply #18 on: May 11, 2012, 07:57:02 AM »
Rudiger,
Thank you for the fast reply.  I cannot get the link in your post to work - it just brings me back to this thread.
Best,
Dan

Offline Roddy

  • Hero Member
  • *****
  • Joined: Feb 2011
  • location: Mount Pleasant,Charleston Co,SC. USA
  • Posts: 607
  • Scan,scan and rescan
  • Unit(s): 797c2, 947c,987SI/DI,570di,1198,1155,Ip
  • Accessories: wx/Tow Fish,Drop Cam's,ROV''s
Re: DYI towfish Mminnesota
« Reply #19 on: May 11, 2012, 08:47:57 AM »
Dan, Nice fish! Take a look at Singleton CAT8 cable the electronic  numbers are a lot better than CAT6 and 1750 lb fail mark.

Roddy
Scan,Scan and Rescan Roddy

Offline danl

  • Newbie
  • *
  • Joined: Feb 2012
  • Posts: 13
Re: DYI towfish Mminnesota
« Reply #20 on: July 24, 2012, 03:35:36 PM »
OK - I have the Cat6 cable (150ft) and am ready to splice into the HDS transducer, but the end plug has 9 pins, and the cable only 8 conductors.
From Rickards' post, I'm assuming the wires from two separate ground pins he shows in the plug photo can be combined, leaving a total of the 8 conductors in the Cat6 cable.
Any advice appreciated.
Thanks,
Dan

Offline Rickard

  • Hero Member
  • *****
  • Joined: May 2009
  • location: Luleå Sweden
  • Posts: 500
  • Unit(s): 999, 981, M37, LowBird-1, LowBird-2
Re: DYI towfish Mminnesota
« Reply #21 on: July 24, 2012, 04:51:45 PM »
Hi Dan,
 
The two grounds in the Lowrance connector may be combined, or any of them can be used alone, in the special application I tested, but this doesn't prove you can do the same in a Lowrance system. My ohm-meter failed due to low battery level, but the resistance can be slightly above zero between the ground pins. This may indicate they actually have separate functions. If you are lucky, one is for temperature primarily, then you need only seven wires in your system. If you can live without temp, that is. And if the Lowrance black box doesn't protest....
 
Rickard

Offline Roddy

  • Hero Member
  • *****
  • Joined: Feb 2011
  • location: Mount Pleasant,Charleston Co,SC. USA
  • Posts: 607
  • Scan,scan and rescan
  • Unit(s): 797c2, 947c,987SI/DI,570di,1198,1155,Ip
  • Accessories: wx/Tow Fish,Drop Cam's,ROV''s
Re: DYI towfish Mminnesota
« Reply #22 on: July 24, 2012, 05:49:57 PM »
Dan, I don't cut the transducer cable, I cut an extension cable 18 inch from each end and splice in the CAT6/8 cable between the two ends.

NO wire pin problems for it is just a in-line splice. Fast and EZ! And saves the transducer cable (in case it has to be sent HB after familiar.

I have been doing a lot of searching with SONARTRX witch is nice to revue with.

Roddy  >:D
« Last Edit: July 24, 2012, 05:51:01 PM by Roddy »
Scan,Scan and Rescan Roddy

Offline danl

  • Newbie
  • *
  • Joined: Feb 2012
  • Posts: 13
Re: DYI towfish Mminnesota
« Reply #23 on: July 24, 2012, 06:07:03 PM »
Rickard,
I have a high quality meter...checked R between what you show as the two ground pins.  I get 4.9Kohms.  Between the two center pins R=9.8K.  R across all other pin combinations shows essentially infinite R.
So now I wonder what the pinout is....

Roddy,
I came to this equipment after someone else started modifying it.  The plug on the transducer cable was plugged into an extension cable and potted in epoxy.  That was plugged into another extension cable and potted.  My plan is to cut the transducer cable just before the potted connection, splice in the Cat6 and add a new connector plug (LTW 9 pin) at the other end of the Cat6 to plug into the base unit.
How many wires are in a HB cable?  This is a Lowrance cable, and until I cut it, I'm not sure of the internal wire count.  Maybe only eight of the 9 pins are being used....

If this was my equipment, I would just experiment, but I'm doing this on county dive team owned equipment and want to be a bit cautious.

Offline danl

  • Newbie
  • *
  • Joined: Feb 2012
  • Posts: 13
Re: DYI towfish Mminnesota
« Reply #24 on: July 24, 2012, 08:01:50 PM »
Here's the cable and plug info for the Lowrance HDS10.
Not sure how the 4-wire-pair Cat6 cable (8 conductors) should be spliced to the Lowrance cable with 9 conductors plus a bare ground.
I'm stumped at this point....
Drawings show wire color, shielded pairs, pin pattern, etc.

Offline Rickard

  • Hero Member
  • *****
  • Joined: May 2009
  • location: Luleå Sweden
  • Posts: 500
  • Unit(s): 999, 981, M37, LowBird-1, LowBird-2
Re: DYI towfish Mminnesota
« Reply #25 on: July 24, 2012, 11:42:59 PM »
Dan,
Have you checked resistance between the conductors and the bare/drain wire?
Rickard
 
I feel like cutting the Lowrance cable now, but I'm leaving for vacation for a week and will have less time for follow-ups.

Offline danl

  • Newbie
  • *
  • Joined: Feb 2012
  • Posts: 13
Re: DYI towfish Mminnesota
« Reply #26 on: July 25, 2012, 05:25:02 AM »
Rickard,
The R between the paired conductors and the bare/ground is infinite...
The only continuity between any wires is where the R values are shown in the drawing.

Offline danl

  • Newbie
  • *
  • Joined: Feb 2012
  • Posts: 13
Re: DYI towfish Mminnesota
« Reply #27 on: July 25, 2012, 09:14:30 AM »
The Cat6 cable was spliced to a Lowrance extension cable.  The Lowrance cable wire colors, the Cat6 wire colors, the plug pin wire colors with Lowrance cable (as original) and plug pin wire colors with Cat6 are shown in the PDF.
Each wire was soldered, insulated with fine shrink tube, the original foil shield re-wrapped over each wire pair.  A thin coat of hot glue was applied and a jacket of shrink tube added over the splice area.  Heat-shrinking the outer tube remelts the hot glue and seals up the splice.
Conductivity of each wire was tested.  Over 150ft of Cat6, the new R for each wire was 5.4 ohms (measured from pin to bare wire at end of Cat6).
This was a test splice.  Plan is to buy matching plugs and solder the Cat6 wires directly into the plug pins.  The final configuration should look like the second attached PDF.

Offline Rickard

  • Hero Member
  • *****
  • Joined: May 2009
  • location: Luleå Sweden
  • Posts: 500
  • Unit(s): 999, 981, M37, LowBird-1, LowBird-2
Re: DYI towfish Mminnesota
« Reply #28 on: August 08, 2012, 04:52:31 AM »
Dan,
 
I checked the resistance again between the pins in the LSS-2 male connector (new battery in the meter now...) and got different results from yours. The resistance between black and grey and between brown and grey in your figure "cable+info.pdf" is about 5.5 K Ohm. Resistance between black and brown seems to be almost zero. These are the same readings as those I got before. Are you absolutely sure your values are correct? If the LSS-2 is an Airmar product there may be two shield layers connected with a capacitor. This can explain why there seems to be two ground pins (black and brown). I see no difference in the results between the ground pins when I run the LSS-2 with my Humminbird SI unit. I'm sure the grey pin is temp.
 
Rickard

Offline dgoldan

  • Newbie
  • *
  • Joined: Aug 2010
  • location: Westminster, CO
  • Posts: 7
  • Unit(s): 987, 997, 1198
  • Accessories: Humviewer
Re: DYI towfish Mminnesota
« Reply #29 on: October 14, 2014, 03:51:31 PM »

3. Does a simple "downrigger" (lead ball with a fin) work as well as a tubular finned fish? 

Anyone have any luck using this method yet?  I have a body recovery at 16,000' of altitude in the Peruvian Andes in 120' of water that I'm trying to build a quick and inexpensive towfish unit for my 1198C Si
South Metro Fire Rescue - Dive Team
Boulder Emergency Squad - Dive Team
Metro Dive Rescue

Offline Roddy

  • Hero Member
  • *****
  • Joined: Feb 2011
  • location: Mount Pleasant,Charleston Co,SC. USA
  • Posts: 607
  • Scan,scan and rescan
  • Unit(s): 797c2, 947c,987SI/DI,570di,1198,1155,Ip
  • Accessories: wx/Tow Fish,Drop Cam's,ROV''s
Re: DYI towfish Mminnesota
« Reply #30 on: October 14, 2014, 08:34:56 PM »
At tow speed 2 to 5 KTS Finned down rigger wt has gone left-right on me very time.
!6,000 Ft alt MSL lake,120 ft deep. NO THANK YOU.  :-*
Scan,Scan and Rescan Roddy

Offline Rüdiger

  • Sr. Member
  • ****
  • Joined: Feb 2011
  • location: Hjältevad Sweden
  • Posts: 427
  • He who seeks finds
  • Unit(s): 898 CX SI ;EAGLE 500CDF
  • Software: DrDepth BT+SS
  • Accessories: Towfish and Towcam
Re: DYI towfish Mminnesota
« Reply #31 on: October 15, 2014, 12:32:42 AM »
Hi dg

An interesting task this search.
Instead of a downrigger also a very heavy towfish (thick-walled iron pipe) would be conceivable.
Whatever you used to bring the fish to depth, it means extra stress for the trailing cable.

mvh
Rüdiger
Sorry
English is not my first language !
http://de.groups.yahoo.com/group/SOB-International/

Offline sonar2000

  • Chief
  • Global Moderator
  • *
  • Joined: May 2009
  • location: Kerr Lake NC
  • Posts: 5970
  • It is not lost ...it has been misplaced.
  • Unit(s): (1) 1197 (1) 1198
  • Software: 6.6
  • Accessories: Tow Fish
Re: DYI towfish Mminnesota
« Reply #32 on: October 15, 2014, 11:43:50 AM »
If you are dealing with a body locater and recovery then quit fooling around with the homemade towfish and get a person or company with a commercial fish made for the depth. We don't have time to keep the family waiting. 
For other purposes the fish you are making looks nice and should help with deeper water images for fishing and wreck location..
Chuck


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo

 

Related Topics

  Subject / Started by Replies Last post
Towfish

Started by keizerh keizerh

5 Replies
5170 Views
Last post September 15, 2009, 01:42:33 PM
by keizerh
19 Replies
17092 Views
Last post September 18, 2012, 01:09:03 AM
by Rüdiger
10 Replies
5091 Views
Last post April 30, 2010, 10:45:33 AM
by sonar2000
15 Replies
9019 Views
Last post January 18, 2011, 03:39:12 PM
by abraquelebout
12 Replies
7600 Views
Last post October 29, 2011, 03:05:11 PM
by nediver
4 Replies
2918 Views
Last post November 07, 2011, 03:22:44 AM
by Jolly Roger
4 Replies
4048 Views
Last post April 29, 2013, 05:32:38 AM
by promapper
3 Replies
3937 Views
Last post July 17, 2013, 11:31:00 AM
by werethefugowee


SimplePortal 2.3.3 © 2008-2010, SimplePortal