View Full Version : Why use a GPS

Darryl Morris
10-19-2006, 06:19 PM
I know that depthfinders and gps units haven't always been around, but they certainly are great tools for catching fish. I've also heard all the old stories of how the fish just used to jump in the boat and all that technology is unnecessary. Well, with all that said, I wanted to share why I use a gps and would like to hear why or why you do not use one or learn to use one effectively.

On a full-day fishing trip I might fish 20 different brushpiles. Using bank lineups it might take say 5 minutes to find, mark and start fishing a pile. With a gps with the WAAS turned on I can get on it and start fishing productive water in about 30 seconds. Saving 4.5 minutes per 20 brushpiles adds 90 minutes (an entire 1.5 hours) of productive fishing for a day's trip. Going back and checking records, I estimate that with just the introduction and use of a gps has increased my catch rate by 20% and I know my clients like it and my boys do too because they love to eat'em.

Bottomline, stop fishing unproductive water and you're certain to catch more fish.

10-19-2006, 06:51 PM
I only fish fresh water in the fall/winter, rest of the time I'm in the Indian River/Mosquito Lagoon (Inshore-salt water) and I generally put in before daylight.
My GPS is indispensible for telling me where all the unmarked poles, shoals, and snags are located, and there are literally dozens and dozens of them.
I just couldn't get anywhere safely without it. Everytime I go out I find more and more stuff to waypoint (like that pole that was just under the surface and put a nice $350 gouge down the side of my new fiberglass boat).
What I've been doing is going out in the day and making "trails" to my favorite spots that I "KNOW" are safe to run WOT, even at night. However, have to always be cautious for crab traps and suprise debris, but I know with certainty I'm not going to slam dead head into an umarked post.
GPS = Couldn't live without it !

10-19-2006, 06:59 PM
You are showing your youth, LOL! The fish finders have been around all my fishing adult life, but not GPS units. For me they are relatively new considering I didn't have one until the 90's sometime, but fish finder, probably got my first one that was really mine in about 1970 when I got my first bass boat. It probably was a flasher unit and we were glad to have that, LOL!

If you have never been caught in the fog day or night without a GPS then you don't know just how nice they are to have for other reasons than just to find the latest brush pile.

Todays electronic equipment is fantastic for sure!

10-19-2006, 07:23 PM
It would be tough finding some of our small brushpiles in the middle of a lake with just line ups of distant banks. Like Morris said ,it's not unusual to fish 20 or more brushpiles on an outing. I never turn my GPS and depth finder off while jig fishing, as I am hopping from one to the next. I rarely fish one more than a few minutes. If they slow down I move. Most times the aggressive slabs bite quickly . I average better fishing more piles for less time each. It helps to have several piles scattered out 100 -200 ft apart to be able to troll to the next one. It takes to much time always moving with the outboard.:) That's why I place my piles in series and keep them small. Hope this has helped.:D

10-19-2006, 07:26 PM
Darryl -- I've never used a gps. Don't know much about them but am considering my first purchase (or a "hey honey, you're always asking what I want for Christmas" suggestion.) I've researched and read, but frankly I don't really know what I'm reading. I will probably go with a hand held model. I don't want to put you on the spot, but what do I need? Can you make any suggestions for a hand held model that will do what you described in your leading post?

Many thanks.


Jerry Blake
10-19-2006, 07:32 PM
This is what I use:


Less than $200 including shipping.

10-19-2006, 07:35 PM
If your on a limited budget and just want to locate waypoints, you can't beat ''Garmin Etrax'':D

Darryl Morris
10-19-2006, 07:48 PM
I've either used or have seen several different gps units. Of them all, the Garmin 76 is the better for the price. It has a larger screen and memory capacity. Really easy to use. The Garmin 76, with a 12v. power cable and a data cable with serial/USB conversion cable and you're in business.

10-19-2006, 08:01 PM
I fish both fresh and saltwater but I use my GPS for both. In saltwater I use it to record my drift lines and mark fish catches. If I have a really good drift I simply try to go directly over the same line. It also makes it easy to see your drift direction especially if it starts to change due to tide or wind. I don't use it a lot in freshwater but one thing it does really well is help you find your way back to the ramp in the dark. So, I use mine for the tracking feature mostly.

Darryl Morris
10-19-2006, 08:13 PM
The tracking feature is great too and I use it on mine alot. When fishing a brushpile it helps me keep a record of where on the brushpile I've previously fished. When trolling it helps me track where I've been so I'll know where to go back to or not.

10-19-2006, 08:13 PM

My question to eagle fish finders...What area does my transducer cover on the back of my baot...I have a eagle fish mark 320...
Here is what eagle replied back with..

Date: Thursday, October 19, 2006 6:59 AM
From: Eagle Info <eagleinfo@lowrance.com>
To: durbinjer@charter.net
Subject: RE: Eagle Other Comment or Question [281604:233918]
Size: 166 KB
Attachments: Cone Angle_v_Coverage Area.doc (158.1 KB)

Thank you for your inquiry.

The word "sonar" is an abbreviation for "SOund, NAvigation and Ranging." It was
developed as a means of tracking enemy submarines during World War II. A sonar
consists of a transmitter, transducer, receiver and display.

The transducer has the capability of telling you the range from the transducer
to the suspended object, however, there is no way to tell where in the cone
angle that object is. The bottom is always directly below the transducer. As a
fish comes into the cone angle, there is no way to tell what side he is coming
into the cone angle. But, you can tell if he is directly below the transducer as
that will provide the strongest signal. When the range of the arch peaks, it is
a think black line, with probably a bit of white on the top, then the fish is
directly below the transducer.

In the simplest terms, an electrical impulse from a transmitter is converted
into a sound wave by the transducer and sent into the water. When this wave
strikes an object, it rebounds. This echo strikes the transducer, which converts
it back into an electric signal, which is amplified by the receiver and sent to
the display. Since the speed of sound in water is constant (approximately 4800
feet per second), the time lapse between the transmitted signal and the received
echo can be measured and the distance to the object determined. This process
repeats itself many times per second.

As mentioned earlier, the sonar unit sends and receives signals, then ?prints?
the echo on the display. Since this happens many times per second, a continuous
line is drawn across the display, showing the bottom signal. In addition, echoes
returned from any object in the water between the surface and bottom are also
displayed. By knowing the speed of sound through water (4800 feet per second)
and the time it takes for the echo to be received, the unit can show the depth
of the water and any fish in the water.

The transducer concentrates the sound into a beam. When a pulse of sound is
transmitted from the transducer, it covers a wider area the deeper it travels.
If you were to plot this on a piece of graph paper, you would find that it
creates a cone shaped pattern, hence the term "cone angle." The sound is
strongest along the center line or axis of the cone and gradually diminishes as
you move away from the center.

In order to measure the transducer's cone angle, the power is first measured at
the center or axis of the cone and then compared to the power as you move away
from the center. When the power drops to half (or -3db[decibels] in electronic
terms), the angle from that center axis is measured. The total angle from the
-3db point on one side of the axis to the -3db point on the other side of the
axis is called the cone angle.

This half power point (-3db) is a standard for the electronics industry and most
manufacturers measure cone angle in this way, but a few use the -10db point
where the power is 1/10 of the center axis power. This gives a greater angle, as
you are measuring a point further away from the center axis. Nothing is
different in transducer performance; only the system of measurement has changed.
For example, a transducer that has an 8 degree cone angle at -3db would have a
16 degree cone angle at -10db.

Lowrance offers transducers with a variety of cone angles. Wide cone angles will
show you more of the underwater world, at the expense of depth capability, since
it spreads the transmitter's power out. Narrow cone angle transducers won't show
you as much of what's around you, but will penetrate deeper than the wide cone.
The narrow cone transducer concentrates the transmitter's power into a smaller
area. A bottom signal on the sonar unit's display will be wider on a wide cone
angle transducer than on a narrow one because you are seeing more of the bottom.
The wide cone's area is much larger than the narrow cone.

High frequency (192 - 200 kHz) transducers come in either a narrow or wide cone
angle. The wide cone angle should be used for most freshwater applications and
the narrow cone angle should be used for all saltwater applications. Low
frequency (50 kHz) sonar transducers are typically in the 30 to 45 degree range.
Although a transducer is most sensitive inside its specified cone angle, you can
also see echoes outside this cone; they just aren't as strong. The effective
cone angle is the area within the specified cone where you can see echoes on the
display. If a fish is suspended inside the transducer's cone, but the
sensitivity is not turned up high enough to see it, then you have a narrow
effective cone angle. You can vary the effective cone angle of the transducer by
varying the receiver's sensitivity. With low sensitivity settings, the effective
cone angle is narrow, showing only targets immediately beneath the transducer
and a shallow bottom. Turning the sensitivity control up increases the effective
cone angle, letting you see targets farther out to the sides.

Attached you will see another document we have explaining cone angle vs.
coverage area.

Please feel free to contact us if we may be of further assistance.

Thank you for choosing Eagle Electronics.

Hope maybe someone can make this more simple for me..