Naval Historywith Dr. Alex

Q&A · 22:35-23:21

Magnetic mapping complicates submarine stealth

Future magnetic-field maps may reveal not only a submarine's positive signature but also the unnatural absence created by imperfect degaussing.

Anti-Submarine WarfareDegaussingMagnetic Anomaly DetectionSubmarinesUndersea Surveillance
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Question

Could precise mapping detect a degaussed submarine as a hole in the surrounding magnetic field?

Short answer

Yes; matching the local field is difficult, and improved magnetic analysis may expose either positive or negative anomalies.

Notes

Degaussing can reduce a submarine's positive magnetic signature, but imperfect cancellation may create a detectable negative anomaly against the local field. In effect, the boat can appear as an unnatural hole rather than as an added magnetic source. True magnetic invisibility would require matching the surrounding field closely as local conditions change. Increasingly precise mapping and analysis could make this a serious anti-submarine detection problem, although the work is still developing.