The sonar I use is an Eagle Optima
it has a 240x240 pixel display this will give you a good display of the
water and bottom conditions I have used other sonar's that have a lower
pixel count and the display they give is quite rough and
"blocky" which is not very good want to "study" the
fish finder and try to work out what it is telling you. As I do a lot of
trolling with a downrigger I like to have the cannonball showing on the
screen .This way I can follow the cannon ball in relation to where it is
from the bottom or any fish that may show on the screen i.e.: if
fish are suspended 40ft down in 60ft of water I can run the cannonball
through the fish marks on the screen
To
do this you should have your transducer mounted on the transom, you then
turn the fish ID off so that you see fish arches (not the cartoon fish),
then lower the cannonball to around 30ft and the if you can reach into
the water and tilt back the transducer, you should see the cannonball
appear as a dark streak right across the screen the at 30ft mark and if
you are using a diving plug you might see a faint streak below the
cannonball. This is your lure!
I
have on occasions seen a fish arch appear just at the lure, this
is a fish having a look at either the lure, cannonball or both.
A far better trolling speed device is the luhr-speed
by luhr jensen this only costs $40 but measures speed to 10th of a mile
it works by having a lead counterweight in the water that acts on a
pivoting arm to display the speed, because the weight is approx 3ft
under the water it is not affected by wind or currents and will display
a constant speed that will allow you to monitor the action of certain
lures at different speeds. It is quite interesting to see at what speed
a spoon will change from a "fluttering" movement to a spin
At
the end of 2003 I updated my Sonar to a Sonar with GPS. I got a Eagle
Sea Charter 320 duel frequency the duel frequency part means it has a
standard and a wide angle "beam" from the transducer I have
mine set on the wide angle beam as it allows me to see the cannonballs
all the way down to 100ft+ also the 320 pixel screen has a much finer
resolution than my previous screen (although the 320 model has now been
superceded by a 480 pixel model).
The
GPS part of this unit was what really interested me it has the facility
to load maps of the waters you fish in "into" the unit and you
will then "see" yourself moving along the screen over
the map. At the moment I have only used mine as a plotter to mark the
trails where we have been, and I have found it great we can troll along
the Endrick bank and leave a trail on the screen that marks the drop-off
and then stay outside that line and leave the cannonballs set at 20 ft
knowing that they wont go crashing into the loch bottom. The trails you
make on the screen will stay in the unit until you erase them, we have
some from Sept 2003 that are saved as our base map with reefs and other
details marked on it, for instance there is a large tree in 25ft of
water just off the mouth of the Endrick we now troll round it or as
close to it as we dare without the risk of snagging our gear on it.
The GPS has also replaced the "Luhr speed" trolling Speedo as
it gives you your speed over ground, we tried it alongside the Luhr
speed and found they gave the same readings so now we just rely on the
Sonar/GPS speed.
