GAL CAN
4'
MAX RANGE
14'
DRAWN
TO SCALE
DETECTION
AREA FOR
SINGLE COIL
6'
21'
MAX DETECTION ENVELOPE ( salt water )
4
PULSE 12 ASSEMBLY ( coil and fish )
Note: All hardware must be of stainless steel. Stainless is not
detectable by almost all kinds of metal detectors.
1. The Tow Arm is bolted to the Fish using two 1/4 - 20x1" stainless
steel bolts, washers, and nuts. Tighten securely, be sure lock
washers are under nuts and tow arm points forward.
2. The Coil mounts to the Fish with four 2" ID X 1/8" O-ring. Be sure
to mount Coil so that the cable is close to the Tow Arm (front of
fish). Stretch the O-rings over the coil and hook them around the
head of the screws protruding out of the front and rear of the coil
supports.
3. Connect the Tow Cable/ rope to the shackle at the top of the Tow
Arm.
The salt water detection envelope is somewhat smaller than the
fresh water detection envelope. This was necessary to reduce
the impact ( meter movement ) of salt water on such a large
search coil.
Figure 4b
9
If your target is small (small anchor, motor, etc.), a slow tow speed
is recommended. If the target passes too quickly below the Coil, you
may get a weak reading on the meter. Experiment by passing a one
gallon can past the Coil while on land. It is recommended that you
use a 1/4" rope between the boat and the downrigger. The
downrigger should be connected to the boat on its own line, so not
to put excessive strain on the Cable. The cable is taped, or wire wrap
tied, to the rope every foot or so. When towing more than one Fish,
a separate downrigger is used for each Fish.
When towing in a highly mineralized area, it will be necessary to
operate in the Salt mode, with the Sample Pulse Delay at four or five.
In this position the effect of minerals is held to a minimum. This
control effects sensitivity for smaller objects - see chart on page 3.
If the control is not set high enough in mineralized areas, then the
meter will move around more than necessary. The meter movement
is caused by the constantly changing distance between the bottom
and the coil as it is being towed close to the bottom.
Cable to
boat
Float
Figure 8b
Figure 8a
Downrigger
25-50#
Downrigger
line from
boat
Cable to
boat
Altimeters attach to the bottom of a Fish and measure the distance
to the bottom. If you did not purchase the Altimeter, then the tow
rope should be marked every five ft and used in conjunction with
your boat depth finder to control Fish depth.
Shallow water ( 2 to 6 ft ) searching is accomplished by tying a float
to the fish ( see Figure 8a ) so that it can be towed behind the boat
without the Fish running into the bottom.
Deepwater searches (over 75 ft ) require a downrigger ( see Figure
8b ) to insure maximum depth of the Fish. The downrigger can be
of any weight - a 25 pound ingot of lead does a good job at low speed
(2-4 MPH). The faster or deeper you tow, the heavier the weight
must be for the Fish to stay directly below the boat to enable
accurate depth control.
