OKM JWF Proton 4 Magnetometers

OKM JWF Proton 4 Magnetometers - Detection of Ship Wrecks

Magnetometers are precision electronic instruments that measure and display the strength of the earth's magnetic field in an area. If ferrous metal is present, the earth's magnetic field is altered and the readout of the magnetometer changes accordingly. Almost every major wreck find was made with a magnetometer. The Spanish galleons laden with gold and silver were also found with magnetometers by detecting the ship's anchors, cannons or cannon balls.

JW Fishers: Magnetometer - Proton 4, Underwater Detector

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.

JW Fishers: Control Box of the marine proton magnetometer

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.

- 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.

- 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.

- 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.

Software Description

JW Fishers: Magnetometer - Software for Proton 4

Fishers Tracker II Software makes it easy to do a thorough magnetometer search of any underwater area. This software is specially designed to work with Fishers Proton 4 magnetometers. Tracker II allows the mag operator to know the exact status of the search at any point in time. Three key pieces of information are shown on the screen. In the upper left of the screen is a graph, with latitude and longitude as the X and Y, showing the path of the boat as it moves through the search area. On the right hand side of the screen are the last 21 mag readouts displayed in a cascading waterfall. At the bottom left of the screen is a graphical representation of the last 5 minutes of readouts displayed in the form of a strip chart, making it easy to see when a target is detected by the spike drawn on the graph. Other information displayed includes the boat's speed and compass heading along with the mag's gamma sensitivity setting and the alarm setting. In addition to the mag readouts, the boat's GPS system can be connected to the mag control box and position coordinates can be displayed with the mag readouts. All data can be stored on the PC hard-drive or disk for future reference.

Using the computer mouse the operator can manipulate either the boat track image or the graphical image of the mag readouts. Clicking on the RESET button will erase the displayed data. Clicking on CENTER button centers the displayed image. The SCALE+ and SCALE– buttons allow the size of the graph to increased or decreased. The boat track image also has an additional button that allows the image to be moved up, down, left or right.

The software is provided on a 3.5", 1.4 MB disk and can be installed on any PC with Windows 95 or above. The program takes up less than 1 MB of space on the computer's hard drive. More than 26,000 mag readouts or 14 hours of recording can be stored on a 1.4 MB disk.

Technical Specifications

The following technical indications are medial values. During operation small variations are quite possible.

Dimensions / Weights
Fish (Length x Diameter, Weight)   52" x 6", 48 lbs
Control Box (L x W x H, Weight)   14" x 10" x 6", 5 lbs
Tow Line (Length x Diameter, Weight)   150 - 1000 x 75", 30 - 200 lbs
Carrying Case (L x W x H, Weight)   59" x 18" x 22", 80 lbs
Total Shipping (L x W x H, Weight)   59" x 18" x 22", 170/320 lbs
Performance / Descriptions
Sensitivity (switch adjustable)   resolves 1 gamma
Maximum detection distance   1,500 feet
Cycle time (switch adjustable)   2 - 4 seconds
Tow speed   1 - 10 MPH
Maximum operating depth (standard unit)   200 feet
Input voltage (two car batteries)   24 vdc
Power consumption   40 Watt
Materials / Colors
Fish   High impact PVC, stainless / yellow
Control Box   High impact case / black
Cable   8 conductor in polypropylene / yellow

Scope of Delivery

In the following table you can see the complete delivery contents and all optional accessories.

The used symbols have the following signification:

x   =   x times included  
  =   Not included
  =    Optionally available, only for additional charge.


Proton 4 Control Box 1
Proton 4 Magnetometer (with 150 ft. cable) 1
... with 300 ft. cable
... with 500 ft. depth rating and 500 ft. cable
... with 1000 ft. depth rating and 1000 ft. cable
... with built in printer (prints gamma and Loran/GPS coordinates)
... with GPS and LORAN interface
... with RS232 output interface (for software usage)
Data collection and storage software (for windows)
UA-2 altimeter (measures distance off bottom)
DDW-1, Deep Dive Wing (deeper towing with less cable)