Towfish Test Box
from Geomatrix

The new and improved Marine Magnetometer tow fish test box. The magnetometer test box is a comprehensive diagnostic tool for checking many functions of Geometrics G‐881/G‐882 Tow Fish systems. The test box permits an operator to verify the status of the magnetometer, tow cable, data telemetry system, altimeter, deck lead and on‐board power supply whilst the system is being deployed on the survey vessel!

The Geomatrix Marine Magnetometer test box analysing the signal strength of a G-882 marine magnetometer.


  • Compatible with all Geometrics Marine Magnetometers.
  • Verification of communication from fish to vessel.
  • Verification of communication vessel to fish.
  • Measurement of current draw by fish with overload protection.
  • Fish simulator mode for testing communications and logging software.
  • Self test mode for power and communications.
  • Dummy load for testing on-board power supply.
  • 240VAC or 30VDC power supply.
  • Test telemetry functionality.

New Features include

  • Altimeter test function
  • Internal battery

The electronics are housed within a rugged Pelican case ensuring that the instrument can withstand the harshest of environments encountered on the back deck of a survey vessel.

An internal rechargeable battery provides power in order to allow the operator freedom to monitor data output from a TowFish on the back deck.

The test box will alert the operator if the external power source surges above 32.9v, ensuring the magnetometer is protected whilst the system is being tested.

Product Dimensions

Physical Dimensions (L x W x H) Weight
Towfish Test Box (instrument only) 24cm x 20cm x 12cm 1.75kg

Technical Specifications

Power Input: Mains -110-240 V AC
Ship Subcon - 32V DC
Banana Sockets- 32V DC
Power Output: Internal supply - 30V DC
Mains/ship supply - 32V DC
Protection: Up to 70V DC on Ship Subcon or banana sockets.
Modes: - Fish Simulator
- Subcon Monitor
- D9 Monitor
- Fish Command
- Altimeter Test
- Self Test


Contents Dimensions (L x W x H) Weight
Mangetometer Test Box
26cm x 22cm x 14cm 2kg