Side Scan Sonar Wanted

GARRYB

Hi All looking for a reasonably priced side scan sonar ,looking on advice to purchase new or second hand ???? Addtionally as my group has little experience in using such a device any tips would be greatly apptreciated .

Regards

Garry

DepthCharge

Try this link Burton Electronics

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Later,
John

It's better to beg forgiveness than ask permission

Genesis

Define "reasonably priced"

Also, what depth of water are you looking to operate in, etc.

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"A venturesome minority will always be eager to get off on their own, and no obstacles should be placed in their path; let them take risks for Godsake, let them get lost, sunburnt, stranded, drowned, eaten by bears, buried alive under avalanches - that is the right and privilege of any free American."
http://www.denninger.net
http://www.diversunion.org/liability.htm - Fix the Diving Cert racket

Johnny Christensen

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Wreckphotography from the cold north

GARRYB

Thanks guys for website info The max depth we will be operating in is 75/80 metres.

Regrdas

GB

Genesis

I looked at this unit for precisely that application about two years ago:

SharkMarine - SportScan

Its not cheap but is cheaper than the others out there with similar capability!

__________________
"A venturesome minority will always be eager to get off on their own, and no obstacles should be placed in their path; let them take risks for Godsake, let them get lost, sunburnt, stranded, drowned, eaten by bears, buried alive under avalanches - that is the right and privilege of any free American."
http://www.denninger.net
http://www.diversunion.org/liability.htm - Fix the Diving Cert racket

koputai

Firstly, the secret of successful sidescan use is to get the fish as deep and close to the bottom as you can. A shallow subtended angle is what gives you definition and makes objects stand out from the bottom clutter. Depth also gets you into the same temperature layer as the object you're looking for, which avoids refraction of the sound waves.
The Sportscan and the Imaginex are the same unit, just different stickers.
In the 80m depth range, that unit will be borderline, and may not give satisfactory results. Ideally with a SSS, you want to fly the fish at an altitude off the bottom of 10 to 20% of your horizontal range. Don't forget too, that the range in the product spec is slant range, not horizontal range.
So, if you use the max range on that unit, which is 120m slant, for good results you need to fly the fish between 10 and 20 metres off the bottom, 60m to 70m water depth. That unit has a max fish depth of 30m.
Running that unit with the fish at 30m, and max range setting, its 60 degree beam wont start hitting the bottom until it's around 50m across from directly below the boat, and will end at around 100m from the boat. In effect you'll be sweeping a path 50m wide starting 50m away from the boat. Much better than a simple downward looking sonar, but pretty useless as far as sidescans go. It seems pretty good in shallow water, but I don't think it's suitable for your depths. Of course, you could luck out and get good results occasionally.

Cheers,
Jason.

Genesis

They have one good to 300 meters for towfish depth, but you won't like the price......

__________________
"A venturesome minority will always be eager to get off on their own, and no obstacles should be placed in their path; let them take risks for Godsake, let them get lost, sunburnt, stranded, drowned, eaten by bears, buried alive under avalanches - that is the right and privilege of any free American."
http://www.denninger.net
http://www.diversunion.org/liability.htm - Fix the Diving Cert racket

Captain Randy

The last time I needed one we rented it. The company I rented from either went out of business or moved but I would bet someone else rents them.

Randy

Johnny Christensen

Hi Jason

The diveboat that I work on from time to time has a SportScan unit. Basicly it's a fine unit, but you have to do some modifications to make it really useful.
The stated depth rating it comes with, has in reallity little to do with it's ability to withstand pressure. Imagenex only supplies a 200 ft / 60m cable as the longest. Should you have a boat that is capable of going only 1-2 knots you may be able to get it down to about 30m, that would be a 45 degree angle of the cable. If you manage to load up the towfish with enough weigths to make a useful tow at that depth, you are doing good.

We had the problem that with only one engine running, the slowest speed we could go was 4,5 knots. So in the factory setup that pulls the towfish to a depth of about 15-20m when letting all 60m of cable out.

The simple solution is to get a longer cable... but you can't do that with the standart setup, as the type of signal the towfish is sending, is barely strong enough to make it thru the 60m of cable in the first place. Therefore the 30m depth limit. We had frequent messages of "lost comunication to sonar" popping up when using it. So we had a little signal converter made and fitted that inside the towfish and also one box that converted the altered signal back to the original format, before it goes into the computer. Now there is a capability to send thru about 500m of cable before the signal gets too weak.

From talking with Imagenex I got the impression that the tail end of the Yellowfin sonar is pretty much like the one on the SportsScan in terms of strengths of the housing. And the Yellowfin is rated to 300m, so we are willing to take our chances that the SportsScan will be fine running in only 1/3 of that depth.

Now, we also had problems with getting the towfish to fly in a straight course. But that one was easily solved when we put a longer body on the unit. It is now 1,7m ~5ft long and have rather large wings to stabilize the flight.

Some modifications required, but when they are done (and they are not that expencive to do) it's a great unit that is serving us well within the 100m depth range.

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Wreckphotography from the cold north