Seek, and ye shall find. Magnetometer technology that helps you do more finding and less seeking.


The SeaSPY towfish is made of ¼” super strong fiberglass coated with a ‘bumper’ layer of polyurethane for extra shock absorption. And the sensor is suspended on shock mounts to ensure the quality of your data isn’t influenced even if you drag SeaSPY along the sea floor.

Self Diagnostics

A quick glance self diagnostic LED system on our isolation transceiver can save you hours of frustration. If all your connections are hooked up properly, a status LED will glow green. If there’s a problem with one of the connections, it will glow yellow. If there’s a short somewhere, it will glow red, and the
transceiver will safely shut down the output power in microseconds. A blue LED flashes with every mag reading. Customers consistently tell us that these features have saved them countless hours in the field.


Should even a drop of water penetrate the towfish, a leak detector warning appears on your screen to inform you. Call us overprotective, but in the event of a breach, SeaSPY’s electronics module is encased in a polycarbonate housing with ‘O’ ring seals for another layer of security.

Better Data

Highest Absolute Accuracy,  If you want good data you have to start with the most accurate sensor. SeaSPY sensors are orders of magnitude more accurate than any other magnetometer: 0.1nT. The repeatability between SeaSPY sensors is also unmatched at better than 0.01nT. Making them the sensor of choice for
gradiometer surveys.

World Wide Operation with No Restrictions

SeaSPY will collect accurate data no matter where you are or in which direction you are surveying. This is not the case with optically pumped magnetometers which have dead zones and must be oriented at a specific angle relative to the earth’s magnetic field. This issue can be particularly problematic in equatorial regions where you cannot collect data in every direction.

Proven Sensitivity Specs

Don’t just take our word for it. We put our sensors under scrutiny, through rigorous independent testing, by a world authority belonging to INTERMAGNET. Intermagnet is the global network of observatories, monitoring the Earth’s magnetic field. The tests confirm our specifications: 0.01nT/ Hz; counter sensitivity is 0.001nT.

Overhauser Effect
SeaSPY is a pulsed Overhauser magnetometer that measures the ambient magnetic field using a specialized branch of nuclear
Magnetic Resonance technology, applied specifically to hydrogen nuclei.

Operating ZonesWorldwide. SeaSPY2 and SeaSPY1 collects accurate results regardless of how it’s pointed in relation to Earth’s magnetic field.
Absolute Accuracy0.1 nT
Sensor Sensitivity0.01 nT
Counter Sensitivity0.001 nT
Resolution0.001 nT
Dead ZoneNONE
Heading ErrorNONE
Temperature DriftNONE
Power Consumption1 W standby, 3 W maximum
Range18,000 nT to 120,000 nT
Gradient ToleranceOver 10,000 nT/m
Sampling Range4 Hz – 0.1 Hz
CommunicationsRS-232, 9600 bps
Power Supply9-30 VDC or 100-240 VAC
Sensitivity0.015 nT
Resolution0.001 nT
Gradient Tolerance> 10,000 nT/m
Range18,000 to 120,000 nT
External Triggerby RS-232
Temperature DriftNONE
Dead ZoneNONE
Heading ErrorNONE
Sampling Rates1/Minute to 1Hz
CommunicationsRS-232, 9600bps