SideScan Sonar wanted

[chris8a]

I'm looking for a low cost Side Scan sonar in good condition that I can use in 10-30 metres of water to find wrecks & fishing spots.
email: [email protected]

[kag00]

For low cost the following are great alternatives.

You could go with transom mount which will work down to max depth of 30 meters. They are a real deal considering price and have integarted echo sounder and GPS charting. Simple to use since there is no towfish with cable to be deployed. Only draw back is they only work well if water is relatively calm. Two companies, Humminbird and Lowarance, see;

http://store.humminbird.com/products...1197c_SI_Combo

http://www.lowrance.com/Products/Mar...StructureScan/

The next alternative is a towed fish system called the starfish. Again this is exceptional value and solves the problems of a hull mount transducer with sea conditions. Slightly more expensive thath the hull mount options above.

http://www.starfishsonar.com/

[Rickard]

Chris,

The most tried and tested systems would be the SI units from Humminbird. There are lots of info here:
http://groups.yahoo.com/group/sideimaging/
http://forums.sideimagingsoft.com/
http://www.xumba.scholleco.com/index.php

Some people have built their own successful towfish systems for their Humminbirds so this option is possible even for these units.

Rickard

[DaveB]

Hi there, I have an Imagenex Sportscan single frequency (330khz) which I may be willing to part with. The unit also comes complete with a depressor wing assembly which enables the fish to swim deeper. This is a fantastic piece of kit which has produced very good results but I don't have the time to go out as much anymore. It hasn't been used much so sensible offer only would be considered!

[chris8a]

Thanks very much guys for the information and offer.
I am currently doing some research to identify what unit would be suitable from a price/function point.

Most manufacturers allow you to download their software and scan files so for evaluation. That's excellent!

There appears to be a big difference in the resolution and range of the units, and a significant difference in software functions.

I may have to stretch the budget to get a better unit, or maybe hire a unit for a month or so. will keep u posted

[abraquelebout]

side scan huminbird

helo
im not speacking verry well inglish, i'm in france near la rochelle.
i'm going to made an home built side scan with 1997 si.
i know that rickard do it.
i use the 1997 si on salt water but there's no good result.(over 10 m)
rickard what conetions do you use, for the ground on the utp cable, do you make a comun conect or independent ground ,?

[Rickard]

Wiring a Humminbird towfish cable

Hi,

I presently use a 50 m ethernet patch cable with metal braiding shield and individually foil shielded twisted pairs. I don't use connectors since I have spliced it in on the original transducer cable permanently. I think this gives much better result compared to a long extension cable that has to use the common ground pin in the transducer connector. Common ground in the connector will result in unbalanced twisted pairs in the extension. On the other hand, my solution require you cut the precious transducer cable.

When you cut the transducer cable you will find it has two shielded twisted pairs, these are the SI circuits. The SI circuits have individual grounds. The wires in each pair must be connected to a pair in the ethernet cable. The black and red wires in the transducer cable are the hot wires for the downward and the temperature channels. They are both grounded through the foil shield and the bare drain wire. The black and the red wire should be connected to their own member of the two remaining twisted pairs. The foil shield and the drain wire in the transducer cable is soldered to the two unused members in the twisted pairs and the shield in the ethernet cable. This arrangment means the downward and the temp circuits are not balanced but that doesn't seem to have any degrading effect. It's possible to arrange grounds in other ways but this method is tested and works well. There is no visible crosstalk between the SI channels with this solution.

These are the colors and connections we used:
(Transducer is the HDSi transducer that came with the 997 model.)

Transducer cable ------- Ethernet cable

Orange -----------------Green
Violet (gnd) -------------White/Green

Yellow ------------------Brown
Brown (gnd) ------------White/Brown

Black -------------------Blue
Red --------------------Orange

Drain (bare) ------------Braiding + White/Blue + White/Orange


A 50 m ethernet cable takes away alot of the receiver signal (but much less than original extension cables do) so there are restrictions on how to operate the towfish. In fresh water the towfish must be within 10 m from the seafloor at 455 kHz. If it is towed higher than that, very little of the bottom will show on the display. The ideal hight seems to be about 5 m over the bottom. Then the system can "see" about 30 m to the right and left and detail is very good.

Regards
Rickard

[abraquelebout]

rickard, thanks a lot for your post.
i want to work on 30m deph salt water. in fresh water no roblem, we find 8 small ship next year on a river. the transducer is at 6 meter and we find 0,20 m object.
the yellow fin and deep wiever softwear help us a lot. the picture are good whith these soft.
i hope that we use 55 m of ethernet cable...
i think that i make a publication of the result in this forum.
we want to find a 400 year old wessel in 26 m of water, with aprobation of drasm (departement of submarine archeology)in france there lot of restrictions.

[Rickard]

I think a 55 m cable should work well also in saltwater, although I can't be 100% sure since I haven't tested my system in water with the salinity I think you have. My towfish weights about 7 kg and I can scan at 30 m depth at 1 knot. Then I still have 10 m cable in the boat.

Have you tried the SiView and Humviewer softwares? I think Humviewer is the most usable program now with all sorts of options, export to GoogleEarth etc etc. You can find links and advice on all viewers here: http://forums.sideimagingsoft.com/
Membership (free) is needed. I think the people at that forum would be very interested to read about your search for the 400 year ship so please join there, if you haven't done that already!

Rickard

[abraquelebout]

i've got humwiever but i thing the picture better in yelow fin or deep wiever.
i have lot of problem with humwiever-google earth.
my pc is full, ...thanks for side imaging forum,i read lot of thing on it.
in fact, near my island there's lot of wreek, sub marine, cargos,war ship and other between 3 to 60 m deph
it's interesting. i'm diver and now we prepare the next search.
lot of boats sim's interresting, we use a magnetometer to find points and we find 7 wreek in 4 years.
best regard
abraquelebout

[chris8a]

Hi Rickard,
Thanks very much for your reply. I have purchased a 998C SI, and built myself a towfish. The scan images seem very good considering the price!!

I have a transducer mounted on the hull, as well as a home-built towfish for deeper water using a 30 foot extension cable. The Hull mounted transducer can see about 45 metres to each side in salt water - which is great!
I purchased a thru hull transducer for the towfish and am experimenting with it. Looking around for a suitable cable to get down a bit deeper. will keep an eye on ebay.
Attached is a scan of a wreck in the local gulf, using the hull mounted transducer. The shadows on the right side have been resolved by moving the transducer nearer to the middle of the boat.
Cheers,
Chris.