Author Topic: yet another topic regarding sonar cable, without need of steel cable. (Read 37050 times)

kron · « **on:** January 21, 2012, 03:22:39 PM »

Hi.

So here we go, with another thread about the controversial sonar cable. Today I have an cat 6 PIMF cable to my towfish, which works very well. However, it needs support so one can tow the fish. The solution is a steel cable attached to the cat 6 cable and of course the towfish. By using two (2) cables the resistance in water is more, and heavier towfish is needed to get it deeper. This makes it often hard to handle/operate the fish. Conclusion of this is smaller diameter of cable will make the resistance less and if only one is used the resistance will decrease really much.

Okay, to my question. Is there any cables out on the market to a reasonable price that only uses one (1) cable for signal and the strength? I will build a rack on the boat so that towfish will be towed in the middle, behind boat ( if towed on side, steering will be suffering allot, due the big forces from towfish). The cable should of course be capable with HB sonar ducers. The cable will be rolled/guided with a pulley and the length of cable be locked in some way (don't know yet, depends on cable). I have seen examples of such cables on this forum, but without information. I guess there is variants of cables with Kevlar inside and cables coated with some armored steel.

Regards

bigkahuna · « **Reply #1 on:** January 21, 2012, 03:59:17 PM »

Falmat Inc ( http://www.falmat.com/ ) makes a Cat 5e cable just for this type of application. It has a very heavy duty PVC cover and a kevlar sheath with a breaking strength of over 1,000 pounds. Part number is FMXCAT50000K12 and last time I asked the price was around $5/ft. You may find a similar product with a wire cover, but that will weigh considerably more and will no doubt require a suitable winch in order to be handled properly. The Falmat cable isn't cheap, but it's probably the best there is for what you're looking for. They also can make custom cables to your specs, don't recall what the minimum order was but it wasn't too much more expensive than the stock cable price.

Roddy · « **Reply #2 on:** January 22, 2012, 12:07:27 AM »

Iron, There is a new cable on the market that may fill our tow fish needs!CAT8,4pr shielded 1700 lb. Brake rating.Water proof.
I received a roll Friday and hope to build a tow fish for 500 feet this week. Roddy

Rüdiger · « **Reply #3 on:** January 22, 2012, 04:09:15 AM »

Hi Kron

Here there is such a cable for around 7 €/m
http://www.seascape.nl/products/video-systems/cables-and-reels/novasub-dlr3

Hi Roddy

Where are the cable and at what costs?

mvh
Rüdiger

Rickard · « **Reply #4 on:** January 22, 2012, 05:14:04 AM »

Daniel,
The reinforced cables are much thicker than the cables I know you (and I) use. The diameter of the Seascape cable is 10 mm, but our cables are 5 mm. The extra steel cable we use is about 3 mm. So the question is: will a 5 mm cable plus a 3 mm wire provide more or less drag than a single reinforced 10 mm cable?
Rickard

Rüdiger · « **Reply #5 on:** January 22, 2012, 05:28:45 AM »

Hi Rickard

I do think that two whatever interconnected cable produce more water resistance than a single cable. In addition, the handling with only one cable is much easier, but unfortunately these enhanced cables are expensive. $:-\$

mvh
Rüdiger

bigkahuna · « **Reply #6 on:** January 22, 2012, 05:33:18 AM »

There's an article in "The ROV Manual" by Robert Christ that may help you answer the question of (form) drag for various cable diameters / shapes: http://books.google.com/books?id=pjW1QoX1KeIC&pg=PA32&lpg=PA32&dq=calculate+form+drag+for+cable&source=bl&ots=AsE4O4k8Dt&sig=kv4IiFII_RitPbjvn7pWSHGpgfQ&hl=en&sa=X&ei=8eIbT_7xBMPctwf4ptTBCw&ved=0CGAQ6AEwBw

Besides the diameter having an effect on the drag of the cable, the shape and surface smoothness effect it as well. A cylinder, which is the basic shape of a cable, can be as much as 2 times as much drag as fusiform/wing shapes. Also how smooth the surface is can also effect drag.

I remember that while I was working for NOAA they were experimenting with various types of drag reducing gizmos for the deep sea buoys we were working on. Those cables were sometimes several miles in length so you can imagine the drag they imposed. If I find a link to info on this I'll post it here.

Rüdiger · « **Reply #7 on:** January 22, 2012, 08:28:20 AM »

Hi

There is also a cheaper option.
One can draw a hollow braided rope over the cable.
I've done in my Towcam and am very satisfied.
http://www.grube.de/online_kat/fachkatalog/index2.php#/?onlinekatpage=H51

mvh
Rüdiger

kron · « **Reply #8 on:** January 22, 2012, 09:15:21 AM »

Quote from: Rüdiger on January 22, 2012, 05:28:45 AM

Hi Rickard

I do think that two whatever interconnected cable produce more water resistance than a single cable. In addition, the handling with only one cable is much easier, but unfortunately these enhanced cables are expensive. $:-\$

mvh
Rüdiger

I think Rüdiger is right there, also what I thought. Haven't done any calculations on it though. But guess if the steel cable was close the signal cable all the time, so steel cable would not be like a bow to the signal cable ( between fixing points) then it might be much better. But this is not so easy at all. Okay one could glue or tape them together. Not what i want. Another disadvantage of using steel cable is "rust". Using in saltwater you "should" change the cable pretty often to be "safer", not losing towfish.

Conclusion: It could even be cheaper in a long-term perspective (one cable), but the initial cost much higher.

Roddy; the cat8 cable sounds interesting, more info and maybe link would be appreciated.

Rüdiger; I have thought about that idea as well. But, I don't think that the signal cable will be protected so good. These ropes are also flexible, which I don't think will work.

Anyway, thanks for all answers and all tips where to get such a cable, its warmly welcome.

bigkahuna · « **Reply #9 on:** January 22, 2012, 09:53:26 AM »

There are several companies (like Falmat that I linked to above) who will build custom cables and the cost isn't that much more than what I posted. In fact, if I recall correctly, the cost was about the same. The expensive part is that they require a minimum order, which if I recall correctly is around 1000 feet. If HB were to provide some specs for an "ideal" cable you could pool your orders together and have some custom cable made with the strength and cover that you want, rather than use something that comes close but isn't exactly the right stuff. Maybe HB can post some guidance or even the specs on the cable that they use, that way you would have some information to start with. I spoke with Falmat a while back and at the time they were very open to help with small projects like this. Might be worth considering.

abraquelebout · « **Reply #10 on:** January 22, 2012, 11:37:44 AM »

for my new river towfish i use a dyneema and the ethernet cable goes inside, 12 mm diameter, no problem

satburn · « **Reply #11 on:** April 11, 2012, 03:35:44 PM »

Hi
Great forum with lots of useful info!

Reading through the forum i saw that most of you guys use cat6 cable.
I have managed to get a hold of a couple of hundred meters of the cable on the attached photo.
This cable is used by the telecommunications company in my country.
It is very strong (the outer shield can withstand any kind of abuse and the 3 yellow wires are made of steel (hard to cut with cutter)
The white is a braid... kevlar maybe.. not sure
Question is, will it matter that there are only 3 pairs of twisted wires? ( the yellow ones run straight )
I will be scanning at 50 meters maximum so i guess 30 meters of wire is sufficient??

Thanks

Rickard · « **Reply #12 on:** April 11, 2012, 03:58:42 PM »

Hi Satburn,

Three pairs are enought. But you will have to sacrifice temperature, though. If you plan for scanning at 50 m I think you should use 50 m with cable. The towfish should be heavy and when making high quality scans at about 1 mph the cable will hang almost straight down.

Please, tell us about your results when your system is finnished!

Regards,
Rickard

satburn · « **Reply #13 on:** April 11, 2012, 05:20:38 PM »

Hi Rickard
Thanks for the reply
Do you think that 6-7 kilos of weight in front of the towfish will be ok?
I will surely get back with the results
Thanks again

Rickard · « **Reply #14 on:** April 11, 2012, 05:26:39 PM »

6 - 7 kg may be ok, but I started at that weight and have added a few kg so the fish now weights about 10 kg. I think that's the upper limit for easy and safe handling of the fish with your bare hands. The heavier, the better.

Rickard

Roddy · « **Reply #15 on:** April 11, 2012, 08:56:56 PM »

Satburn, Richard has a important point, the weight has to heavy enough to keep the fish down but light enough to be retrieved by hand or hand crank reel.

One to three kits max tow speed gives the best screen shots.

Always build the system so there will be at lest 20m of extra cable in case of a hang.

Roddy

newkid4si · « **Reply #16 on:** April 11, 2012, 11:51:52 PM »

I have a suggestion you may not have thought of. What about using a downrigger like is used in fishing to control your towfish depth?
The downrigger would be able to control the vertical depth of the fish to a matter of inches. Some have depth counters on them.
They come in manual and electric. The distance of the fish behind the boat could be as short as a couple of feet depending on how you
attach it to the weight/clip harness.
The weight on the downrigger would be what pulls the connecting cable ( fish to unit) and fish down as opposed to the weight of the fish.
This would solve the problem of water pressure on a long length of cable. This may also result in the need for a smaller fish as added weight for depth wouldn't be needed.

Gattlin · « **Reply #17 on:** April 12, 2012, 01:25:01 AM »

I may be totally out of my league here. But just trying to help. I put in a request for the smart cast system be implemented with a side planer would that not also solve the problem of wire? With less wire could a person not achieve a stable platform with a little extra battery weight? Just wondering good Luck Skinner.

Roddy · « **Reply #18 on:** April 12, 2012, 11:04:44 AM »

Gattlin, Wonderfull thinking your on to something!

I have been working on something on along these line for a remotely operated platform.

satburn · « **Reply #19 on:** April 12, 2012, 02:07:31 PM »

Thank you all for the advice

@ newkid4si
I do have a downrigger with a depth counter (a scotty) and i like your idea so i will go that way.
Maybe adjust the weight of the fish so it's slightly negative buoyant?.. well i guess it's a matter of trial and error

I will post back the results.
Thanks

newkid4si · « **Reply #20 on:** April 12, 2012, 09:43:18 PM »

If the downrigger would work, and I think it at least deserves a try; here are a couple advantages.
The fish could be attached with a short dropback lead so that if you need to stop, the fish would
pendulum down and still not hit bottom. Example- 60 FOW- downrigger @ 50'-- dropback @ 5'
This would locate the fish at 10' above bottom during the scan, but if you need to stop, the fish
is still 5' above it.
The other advantage would be during turning. Instead of a couple hundred feet of tow line,
you could do a 180 degree turn practically.

sonar2000 · « **Reply #21 on:** April 13, 2012, 09:39:47 AM »

Guys, let us know how this works out. I really see several good factors with this and it might save a fish.

As you proceed with the project post some picture.
Both here in a topic and again add to the installation section in the media tab.

Thanks for being so creative. It certainly shows some well thought out improvements..

Chuck

Roddy · « **Reply #22 on:** April 14, 2012, 11:26:07 AM »

OK, One of my first tow fish used a Lake Systems downrigger 250 ft 250 lb ss coated cable 10 lb ball wt.

Crab bait clips were installed on the rigger cable free sliding and then clipped to the tow fish cable at 5 ft increment's.

Worked good in rivers, nice flat water, played hell at sea in 3 + seas fish jumped with each passing sea.

The down rigger weight did not allow for any dampping of the boat as the seas passed.

newkid4si · « **Reply #23 on:** April 14, 2012, 05:10:00 PM »

Roddy
As soon as I saw "played hell at sea in 3 + seas ", I thought... yep- that's going to be a problem.
Good to know the idea will work under some conditions. A time and place for each method.
For the guys pulling fishing lures instead of towfish, the surge / slack line would probably be an advantage.
Out of curiosity, how far back would you need to be on a normal towline to dampen the boat movement?

Kron-- Went back and read the original topic and I feel I'm in the " gray area of a hijack " so I'll quit. Sorry.
I tried to stay on topic, but as you get older, you sorta just drift off....

Roddy · « **Reply #24 on:** April 14, 2012, 10:19:51 PM »

Korn, Sorry about the hijacking, ti happends to the best of us.

I just built a new tow fish using 22ga, 4pr, @ 1750 lb working 2500 lb braking strength. I will find and post ordering and website info as soon as i can find it.

Newkid4si, As for drop back I have found that each fish/cable comb will be different. There is not a hard and fast rule.

Some of the variables are, boat speed, legnth of cable out, cable diameter, tow fish weight, water temperature, water density, water depth tow fish is working at (tow fish depth).

Or add enough weight to get it down where you need it!

I have used as much as water depth plus 30% on deep runs.

Enjoy and smooth seas! Roddy

kron · « **Reply #25 on:** April 15, 2012, 05:44:57 AM »

Hi everyone!

Well I have followed all the "new" posts and it is true that it might be little of topic. But for me it doesn't matter. I think that you all should use this topic to the new off topic questions because many people now know where to find them. unfortunately I can not contribute as much to this. I still have the problem where to find a new cable with the strength, and I am looking forward to see a post with the cable you are using Roddy.

I don't know if this is an good idea or not, but many topics are after a while getting of topic. For the people that are following them this might not be a big problem. But it can be for many others. My suggestion is then that every post should be colour market after its content, by the poster. For instance. When the topic is created the poster then decide a colour "theme" for the posts containing what the headline says. And then when other people reply they can choose the same colour "theme" to their own post. And if there is an of topic question (not being an direct answer or question to the headline) the poster has to choose another colour "theme", and the following replies on that question/statements should be in the same colour.

It's only an idea. One can think that of topics should never appear, but I think that it sometimes like in this thread can be good because, it's not an direct statement to the headline, but a part of it.

sonar2000 · « **Reply #26 on:** April 15, 2012, 08:40:29 AM »

Right on target Kron. And I am guilty also.

OK I will do two things.

A wish list for color

and another posting etiquite..

Thanks Chuck

Roddy · « **Reply #27 on:** April 15, 2012, 10:47:59 PM »

I'am guilty, back to my cave.

Gattlin · « **Reply #28 on:** April 15, 2012, 11:31:46 PM »

I do not mean to get off subject which I'm not. The tinsel strength of the cable will all be you'll need in the near future. But then again stock holders have options.
The power,,to power such a device might have an inherit need of diameter and circumference.

But then again GPS

coordinate for Search and rescue are A might different I would predispose.

Roddy · « **Reply #29 on:** April 18, 2012, 10:44:31 PM »

Rudiger, Ref: cat 8 cable

Singlepoint networks, cat8 cable multimedia cable, 22/1, 4pr shielded.

cat5, max 155MHz
cat6, max 400MHz
cat7, max 625MHz
cat8, max 1200MHz (1.2 GHz capable of 1400 MHz).

Rüdiger · « **Reply #30 on:** April 19, 2012, 08:51:46 AM »

Hi Roddy

I've searched in Google about cat8 patch cable, but found only max. cat7

mvh
Rüdiger

Roddy · « **Reply #31 on:** April 19, 2012, 09:41:39 AM »

Rudiger, Google Singlepoint networks.

Rüdiger · « **Reply #32 on:** April 19, 2012, 10:10:51 AM »

HI Roddy

I have found it, but it is only a installation cable

not a flexible cable.

mvh
Rüdiger

Quote from: Roddy on April 19, 2012, 09:41:39 AM

Rudiger, Google Singlepoint networks.

Roddy · « **Reply #33 on:** April 19, 2012, 04:20:08 PM »

IT WORKS. Roddy

kron · « **Reply #34 on:** July 10, 2013, 04:27:10 PM »

Hi again.

It has been a long time ago since my last post. Have spent the last 5 months for studies in Singapore.
Now I definitely need a new cable because the last time out scanning was probably the last time with the one I have right now (cat6 PIMF). The reason!?: I got more and more noise on the screen which was probably caused by bad connection somewhere in the cable. Salt water have probably leaked into the cable due fatigue to the cable during all the years it has been used.

As stated before, I want only one cable. It is expensive, that's true, but it will maybe be much better!?

What do you guys think about this cable?

http://www.universalnetworks.co.uk/product.htm?product=External-Grade-Steel-Wire-Armoured-Shielded-Cat6-Cable

My biggest concern is that the pairs are not in metal foil (PIMF). i.e. separately shielded.

Rickard · « **Reply #35 on:** July 11, 2013, 04:06:29 PM »

Hi Daniel,

And welcome back! The cable looks very resistant. They don't tell the tensile strength in the specs, but with that steel armour it should be strong enought for a towfish. The lack of sheild for the individual pairs may be an issue, though. I tested with a cheap UTP cable and got severe crosstalk betweeen the SI channels, but that cable was 100 m long. It's difficult to say how much crosstalk there will be in a high-end cable half that long. I'm afraid you will have to test the cable before you know...

Rickard

wreckreationaldivers · « **Reply #36 on:** July 12, 2013, 01:38:03 AM »

There a plenty of cable manufactures who make three coax's in one heavy duty cable, has anyone thought about using 3 coax's and disregarding the temp's (positive fired/received down the centre & negative using the screen) all 3 negatives go to ground in the humminbird plug plus down & temp use the drain for a return?

abraquelebout · « **Reply #37 on:** July 12, 2013, 08:03:12 AM »

for my next towfish (in contruction) i get cat7a sftp câble
it look resistant to tract the towfish lonly
i think take two wire to connect the down Lss2 in right or left side humminbird and separate them with an Y
in one way all the function, on the other T°, 200khz and down Lss2
result in few week...

rnvinc · « **Reply #38 on:** July 12, 2013, 09:51:19 PM »

Quote from: abraquelebout on July 12, 2013, 08:03:12 AM

for my next towfish (in contruction) i get cat7a sftp câble
it look resistant to tract the towfish lonly
i think take two wire to connect the down Lss2 in right or left side humminbird and separate them with an Y
in one way all the function, on the other T°, 200khz and down Lss2
result in few week...

Abra...my initial DownScan testing using the LSS 2 thru the HB right SI channel... I connected the LSS 2 temp channel to the HB temp channel in my 1197...

The LSS 2 did read temperature on the HB ... but it read +30° F of actual water temp...

Have you got any similar results...??

Rickie

abraquelebout · « **Reply #39 on:** July 13, 2013, 03:16:53 AM »

HI rnvinc
for the T° i take it on the hdsi ducer, i use a 898 si
T° and 200 khz on Hdsi ducer
do you have picture take in down scan with Lss2 ?
i wonder if it's better to make down scan with Lss2
or make a connection in Hdsi to take a good 800 khz (Lss2 not work well at 800 khz)
and exit T°

rnvinc · « **Reply #40 on:** July 13, 2013, 06:51:56 AM »

Abra ... See here starting at about reply #187...

http://forums.sideimagingsoft.com/index.php?topic=5388.msg36950#quickreply

I've only had 1 day of testing the LSS 2 DownScan element thru the HB right SI channel...

My shallow water testing shows double imaging in the structure being displayed...

Rickard explains this possibility as the sidelobes being so large or possible nearfield ripples in the LSS 2 thinner beam..

I will be testing further in deeper water and with different software versions ...

I'm hoping some other guys may feel compelled to experiment with the LSS 2 DownScan element also to see if we can figure out how to get acceptable DownScan images...

As of yet, I have heard of no others that have experimented with the LSS 2 DownScan element in the HB SI ...

Rickie

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