Recreational salvaging... Questions...

[RW]

I have never really used a sonar. I picked up a blowout special Humminbird 718 for $70 about six months ago and still haven't hooked it up yet. Is there a better way to rig the transducer for bottom detail than the way the instructions suggest? Would a down rigger or tow fish help with detail? My goals are pretty simple to start. I plan on scanning freshwater lakes in the 20' deep range. Will I be able to recognize anomalies as small as props with this unit? I have a Tiger Shark and am considering a diving hookah. Rare earth magnets on a rope or a grappling hook might also be in my start-up arsenal. Really just looking for a reason to spend more time on the water and maybe make a couple bucks. Or grow... Tips and ideas GREATLY appreciated!
Thanks, Ron

 

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[Jason in Enid]

No, that is a fishfinder, not a side scan sonar.

For a bare-minimum SSS (which is still a far cry from commercial units) would be the Hummingbird 1198c.

Standard fishfinders/depthfinders have a resolution measured in meters. You are lucky if you can spot a sunken boat, directly underneath you.

 

[RW]

Lucky to see a sunken boat at 20'? That just plain sucks. Specs claim target separation is 2.5". Using the 200khz 20 degree beam at 20' depth I was hoping for a decent 20' wide view of the bottom. Not being concerned with what is in the water column, I was hoping to be able to hone in on the bottom. The pictures on the box really look bad, and I am sure those are better than consumer operator could achieve. So I guess I got my father-in-law a Christmas present now... I am not even sure how to interpret what the screen is showing... And what significance is the SIDE in SSS?

 

[rgecy]

Ron,

A traditional 2d sonar will not give you any significant detail when looking for objects on the bottom. Take a look at some of the images you can get using the Humminbird Side Scan units.

http://forums.sideimagingsoft.com/index.php?action=media

Robert

 

[RW]

Ron,

A traditional 2d sonar will not give you any significant detail when looking for objects on the bottom. Take a look at some of the images you can get using the Humminbird Side Scan units.

http://forums.sideimagingsoft.com/index.php?action=media

Robert

Wow! I have a lot to learn. Is the technology jumping leaps and bounds every year? Or would a used unit be adequate for a while? Every time I buy a camera/video related product they come out with HD for half price the next week.

Do you know of a good link that describes the basics of SSS? Basics like how many transducers? What is the road looking line down the middle? Depth related to detail? Anything! Thanks again for the link to sideimagesoft. I am sure all of the information is there and I will get it in time. Just looking for the Cliff Notes...
Thanks again, Ron

 

[Galleon Hunter]

You ask...And what is the side in SSS?

This picture perhaps can best give a visual of how sidescan works, pretend the sun is your tow fish. The camels (or wreck) is directly beneath you... you can't "SEE" the camels. Well they are the bright white objects, the white side towards the sun (sonar) and the black (the acoustic void, that generates the shadow) What you are seeing on the desert floor is their shadows, much like the acoustic shadow of something sticking up off the ocean floor. Which is why it is better to find a target at the extent of your range and NOT go directly over it... to make the object cast as good a shadow as possible, then you can combine the range, shadow length, and width to establish height off the bottom of the sea floor.

http://www.slightlywarped.com/crapfactory/amazingimages/camels.htm

Hope this visual helps (they say a pic is worth 1000 words)

 

[FISHEYE]

If you turn a fish finder transducer sideways you will see protrusions from the bottom but the image will be very poor.You can arrange 4 transducers in a array and get better images.

This forum will tell you how to do it.
http://thunting.com/smf/side_scan_sonar-b180.0/

Also this one but some links are bad.
http://www.geotech1.com/forums/archive/index.php/f-10.html

This link explains SS arrays
http://www.beugungsbild.de/sidescan/sidescan.html

Heres a product survey on all SS's manufactured
http://www.hydro-international.com/productsurvey/id30-Sidescan_Sonar,_NovemberDecember.html

 

[Jason in Enid]

Galleon, that is the best picture for explaining the use of SSS!

 

[RW]

Yes thanks for all of the posts, links and replies. The SIDE being where the definition lies. Would love to have one and may do so after researching the snot out of them. For now I will be content with snorkeling until a hookah becomes available to me. You don't really find many SSS image examples at the 20' depth. SSS, ROV are just a wee bit out of my comfort zone, but it may just take some warming up to...

 

[stevemc]

RW, Humminbird makes several sizes of side scan, 700, 900 and 1100 series. That is the size of the screen in inches diagonal, 7", 9", and 11". Of course the larger the better. But you can get a 7" for less than $1000 on Ebay. The 1100s are $2500 or so.

 

[RW]

RW, Humminbird makes several sizes of side scan, 700, 900 and 1100 series. That is the size of the screen in inches diagonal, 7", 9", and 11". Of course the larger the better. But you can get a 7" for less than $1000 on Ebay. The 1100s are $2500 or so.

Thanks for the heads up, I didn't know that. Wonder if they 700 series would be the same size as the 718 I have now but yet to install? Also wonder if there is a monitor out to use a laptop for screen? Some of the pics from the Humminbirds are incredible.