We have now completed the first full Antarctic season using our SeaSPY magnetometer and can report that we are delighted with its performance. It has proved to be very robust and trouble free in operation and has delivered consistently good data. There is no doubt that we chose the right instrument.

Peter Morris
British Antarctic Survey

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Box SeaSpy

Start Up

A 1000m SeaSPY magnetometer with electronics module and sensor configuration comes with:

SeaSPY is available with many options and accessories. Please contact us to discuss your specific needs.


Crystal Clear

SeaSPY’s accuracy is 0.1nT—the highest absolute accuracy of any magnetometer on the market. No matter where you are or in which direction you are surveying, SeaSPY gives you consistent, repeatable data you can trust.


Go-Anywhere Accuracy

SeaSPY sensors don’t require temperature stabilization, so work in any water instantly, on power up. The clock used in the SeaSPY electronics module is accurate to 1ppm throughout the entire temperature range, so the data will always be accurately time stamped and match up perfectly with base station information.



Our connectors are custom made from brass and support a tonne of towing force. A nose cone protects it from side impacts, while maintaining a streamlined tow body.

We have never lost a SeaSPY from the connector, except for the time someone threw one overboard without connecting it to the cable. While there’s some human error no mag can account for, the story has a happy ending: the customer went back a year later and found their SeaSPY in working condition.


Stable Time

The clock used in the SeaSPY electronics module is accurate to 1ppm throughout the entire temperature range, (as opposed to 100ppm found in competing magnetometer systems) so it will be accurately time stamped to sync with diurnal correction (base station) information.


Takes a Licking

Attacked by sharks. Cast adrift. Dragged on the ocean floor. No matter what happens in the field, SeaSPY keeps on working. With its tough exterior, snag-resistant design and shock-mounted sensor, SeaSPY is made to survive anything you can throw at it. And it won’t even hold a grudge.


Sleek Design

SeaSPY’s sleek design resists snags. The inexpensive and field replaceable tailfins are the only protruding element, and they are designed to snap off should they ever get snagged on rocky outcroppings.


Tried and True

After more than a decade in the field, SeaSPY remains the most user-friendly magnetometer around. Its low power consumption, easy integration capabilities, self-diagnostic LED system and maintenance-free sensors make it easy for you to get better data.



A leak sensor in the towfish, triggered by the smallest drop of water, alerts you to a breach immediately, so you can repair the faulty seal with no damage to the instrument. LED’s on the topside unit give you at-a-glance awareness of your tow system status, and continuous self-diagnostics during sampling ensure erroneous data won’t be interpreted as correct.


Easy to Use

SeaSPY’s low power requirements – 1W standby and 3W maximum – means it will run up to 150 hours on a typical car battery. And SeaSPY easily integrates with side scan sonars and other platforms, with no modifications or additional accessories needed.


Maintenance-Free Sensors

SeaSPY sensors don’t degrade with time, so you’ll get the same quality data after 10 years of use as you did the first time you used it.

In addition SeaSPY sensors contain no consumable parts, so you won’t have to replace anything, like the expensive lamps that wear out in optically pumped mags.


Sunny Disposition in Any Latitude

SeaSPY is equally at home in the arctic as it is in the tropics. Just throw it overboard, and it starts working instantly, on power-up. Wherever you are, your data stays constant—even when the temperature doesn’t.



The SeaSPY towfish is made of ¼” super strong fiberglass, coated with a “bumper” layer of polyurethane for extra shock absorption. The sensor itself is suspended on shock mounts, so even if you drag SeaSPY along the ocean floor, your sensor won’t feel a thing.


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.



SeaSPY’s Overhauser sensor has no ‘dead zone’, meaning it will produce great results, regardless of the direction of the ambient magnetic field. You can survey in any direction, anywhere in the world, without worrying about aligning the sensor to the Earth’s field, as you need to do with many competing systems.