Sidescan & Magnetometer for Newbies

[aussiejohn]

Hi Guys,
I've just joined and am looking into Sidescan and Magnetometers for amateur shipwreck searching.

I'm located in Sydney, Australia - a lot of the wrecks in question are steam ships or WWII wrecks built over the last century.

Depths up to about 500 feet.

We're experienced deep wreck divers, have borrowed a basic magnetometer 10 years ago and would appreciate an update re. the state of play at the moment. Ideally pros, cons, costs, suggestions etc.

Thanks for your help (and sorry if this sort of thread has already been posted in the past).

Cheers,

John

[chipveres]

www.quantrosensing.com has mags that normal people can afford. J.W. Fishers has excellent units but you must be spending OPM (other people's money).

Chip V.

[ping]

Sidescan and Magnetometers;

I have used pretty much every type of sidescan and mag in the professional market. Love to help.

If you adopt a professional attitude and do a survey correctly, your chances of success go way way up. The best way to look for any type of submerged contact, wherein you may have to search several dozen or hundred square kilometers, is with combined sidescan and mag. The most important thing is to make sure you use a sonar processor to generate 2-D sidescan mosaics with a magnetic field map draped over the sonar. You will be instantly able to define your targets, spot debris trails, and determine the best places to dig with great accuracy. Without that step, your chances of success are extremely limited.

Mag;
For wreck detection, you should use a 'differential gradiometer' and not just a simple magnetic sensor. The differential gradiometer is a device that uses several very sensitive magnetic sensors in a small grid. The device looks for the 'difference' between the magnetic field strength on the sensors, and thus, it can ignore local geological magnetic signatures and respond mostly to man made contacts. This is the best one;. Have used them many times, works extremely well.

http://www.marinemagnetics.com/

Sidescan;

GeoAcoustics (sidescan, also sells sonar processors that can do the above)
www.geoacoustics.com
Excellent sidescan units, the older analog units work extremely well also.

EdgeTech; - also, excellent sidescan units
http://www.edgetech.com/

http://www.l-3com.com
I have used their model 3000 with very good results


Hope that helps.

[cliffscot]

What kind of sonar processing are you using? Can it be used universally I have a poor boy set-up hummingbird & quantro sensing mag.

Thanks

[ping]

Sorry Cliffscot.

The hummingbird unit has no facility to export data, and that means it can't be used with any type of sonar processor.

P

[Salvor6]

Sorry Ping,
the Humminbird DOES have a memory card to export data. There is also excellent software to process the data. This has all been posted on the "shipwreck" forum. http://www.forum.treasurenet.com/ind...,124276.0.html.

[ping]

Yes, you are right!

I just found what you mentioned. I hereby hang my head down in shame and repent . .

Sorry, I have used the Humminbird sonar before and wasn't very impressed. However, it is cheap.

The Tritech 'starfish' has much, much better performance and doesn't cost a whole lot more. Check that out before you get into a Humminbird sidescan.

P

[Salvor6]

Hey ping, could you post a link to the Tritech web site. I can't find it.