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Just to illustrate the detection ranges that can be achieved with a magnetometer, here are some figures.
Magnetic anomaly in gammas = 104.A/B.w/d3 where A/B is the ratio of length to width of the object, w = weight of the object in gm and d = distance of object in cm.
Assuming that 5 gammas is detectable, then for a sunken iron ship or submarine the detection distance in metres, D, is the cube root of 104.W (W = weight of object in tons).
This gives:- 10 ton ship detectable at 45m.
100 ton ship detectable at 100m.
1000 ton ship detectable at 200m.
10,000 ton ship detectable at 450m.
Smaller objects:-20lb cannon ball detectable at 3m.
2cwt anchor detectable at 10m.
2 ton cannon detectable at 27m.
All right hand digits is the above formulae are superscripts.
Eric.
Magnetic anomaly in gammas = 104.A/B.w/d3 where A/B is the ratio of length to width of the object, w = weight of the object in gm and d = distance of object in cm.
Assuming that 5 gammas is detectable, then for a sunken iron ship or submarine the detection distance in metres, D, is the cube root of 104.W (W = weight of object in tons).
This gives:- 10 ton ship detectable at 45m.
100 ton ship detectable at 100m.
1000 ton ship detectable at 200m.
10,000 ton ship detectable at 450m.
Smaller objects:-20lb cannon ball detectable at 3m.
2cwt anchor detectable at 10m.
2 ton cannon detectable at 27m.
All right hand digits is the above formulae are superscripts.
Eric.