The Proton 4 is a fourth generation proton magnetometer from
JW Fishers. It is a top performing microprocessor driven marine magnetometer detection system.
With a one gamma sensitivity, it has the maximum usable sensitivity for a towed magnetometer. A two second cycle time
gives a strong return signal and is fast enough to detect even small iron/steel targets. The Proton 4 features a triaxial
noise-cancelling sensor that allows omnidirectional towing without heading error or dead zone. The system is fully digitized
and displays it's output on an easy to read 5 digit LCD that is backlit for night operations.
The optional built-in printer creates a permanent record of the mag readouts. The gamma reading
is printed out on each cycle and, with input from a GPS receiver, the target's position is also printed out. An alarm informs the
operator when the readout changes. An RS232 output and software package are also available. The Fish has excellent
hydrodynamic characteristics moving smoothly through the water at tow speeds up to 10 knots. A 2 - 3 knot tow speed is recommended
for small targets. With the optional Altimeter, precise distance off the bottom can be maintained. For deep water towing, the
Fish is towed behind a downrigger. The Fish can be towed at almost any speed, but should be towed slow to locate small targets
or when towing the Fish deep. A sensitivity switch allows easy pinpointing of targets.
Modular construction allows easy field repair, should it ever be necessary.
The Proton 4 is a proton magnetometer that was specially designed
for underwater salvage work. The system consists of a Control Box, a 150 - 1000' cable and a towfish.
FISH - The Fish is 52 inches long and has a watertight compartment that contains the sensors and the
electronics necessary for processing the signal before sending to the control box. The Fish has four fins
for stability and is weighted for negative buoyancy. The materials used in the construction of the Fish were
specifically selected for high impact resistance and low maintenance.
CABLE - The 150 - 1000' tow cable consists of multi-paired and coax cables encased inside a braided
polypropylene rope. The combination results in a highly abrasion-resistant tow cable.
CONTROL BOX - The Control Box receives signals from the fish and does additional processing for display
on the digital readout. On the face of the Control Box are the following controls and displays:
||Readout - A five digit LCD readout displays the gamma reading. The readout is backlit for nighttime viewing.
||Sensitivity Switch - A four position switch allows the sensitivity to be reduced once a target area is
located, so the target can be accurately pinpointed.
||Pol Time - A three position switch controls the cycle time. 2.5, 3 or 4 seconds can be selected.
||Alarm - A seven position switch sounds an alarm if the readout changes beyond the selected gamma amount.
||Printer (option) - A 24 column printer prints out the gamma reading and sensitivity switch setting each
cycle and prints out the LORAN or GPS coordinates after every fifth cycle.
Operation and Use
When you receive your Proton 4, it has been tuned at the factory and is ready to operate; all you need are two 12 Volt batteries
(car or marine type) for power. The Power On switch on the Control Box is turned on and the unit automatically begins
cycling. The gamma reading and LORAN or GPS coordinates will be printed. With the optional RS232 output interface the
information can be output to any computer or software program.
When towing the Fish, as you approach a ferromagnetic target, the readout number will decrease; the amount of decrease will
depend on the size of the target and how close the Fish passes to it. A change of several thousand can be expected for
a very large target. The Proton 4 can easily pinpoint wrecks.