The Humminbird 997
I'm not going to start
off by declaring I'm
an expert, all I want to
do here is pass on
some thoughts, tricks
and twist I've had
about these side scan
units.
off by declaring I'm
an expert, all I want to
do here is pass on
some thoughts, tricks
and twist I've had
about these side scan
units.
I've been interested in side scan for years but the nature of the
beast made it hard to use and expensive till Humminbird came
up with this sport fishing version. With the transom mounted
transducer instead of a tow fish, it became an every day usable
sonar. Then toss in Humminbird figured out how you could get
a very good approximate distance out from the boat to make
way points and you have the workings a technological jump in
sonars.
beast made it hard to use and expensive till Humminbird came
up with this sport fishing version. With the transom mounted
transducer instead of a tow fish, it became an every day usable
sonar. Then toss in Humminbird figured out how you could get
a very good approximate distance out from the boat to make
way points and you have the workings a technological jump in
sonars.
| Under contruction drive careful |
Now we have the way to
completely visualize the
structure beneath. This
image beside, you can
tell there is a steep
slope running from the
upper left to lower right.
completely visualize the
structure beneath. This
image beside, you can
tell there is a steep
slope running from the
upper left to lower right.
In this case we can see by the black area each side of the
center line, called the water column, as it gets deeper this
width increase because of the increased time it takes for the
sonar to go from the transducer and back. Also in the image
you can see a shadow area in the middle right of the image
caused by the sonar over shooting the high ground. A lot of
times your going to find shadows help in determining what an
object might be. Its also one of the best way to spot fish.
center line, called the water column, as it gets deeper this
width increase because of the increased time it takes for the
sonar to go from the transducer and back. Also in the image
you can see a shadow area in the middle right of the image
caused by the sonar over shooting the high ground. A lot of
times your going to find shadows help in determining what an
object might be. Its also one of the best way to spot fish.
| More to come as I get time. |
| Unofficial thoughts |
I'll likely edit this later but for now, how using both sides vs
one side and how speed and distance from center
line of an object affect how it looks. In each screen capture
you can check speed, scan width and the position from
Center Line, of a boat I found this summer on the image.
Be sure to check the last two images closely. If you look at
the front of the boat you'll see a grove in the lake bottom
where the boat must have been dragged backwards. That
had to have been an interesting experience for some one. I
figure they got a anchor hung up in it so they tied the rope off
and tried gunning the motor to pull it loose. What they ended
up doing is dragging the boat from 9 feet of water on top the
point, down the side slope into 13 on the front and 18 on the
back. I'm betting their boat almost swamped trying this. If
you'd like to see the boat, and all the fish line snagged on it,
you can check it out in the video's. The fish lines almost look
like ropes now with all the algea on them.
one side and how speed and distance from center
line of an object affect how it looks. In each screen capture
you can check speed, scan width and the position from
Center Line, of a boat I found this summer on the image.
Be sure to check the last two images closely. If you look at
the front of the boat you'll see a grove in the lake bottom
where the boat must have been dragged backwards. That
had to have been an interesting experience for some one. I
figure they got a anchor hung up in it so they tied the rope off
and tried gunning the motor to pull it loose. What they ended
up doing is dragging the boat from 9 feet of water on top the
point, down the side slope into 13 on the front and 18 on the
back. I'm betting their boat almost swamped trying this. If
you'd like to see the boat, and all the fish line snagged on it,
you can check it out in the video's. The fish lines almost look
like ropes now with all the algea on them.
Some thing for you guys already using the side scans. How
bright some thing shows up on the screen is determined by
its hardness, or reflectivity, and the angle the sonar wave
strikes it. If you've run your unit with it set to wide sides, say
over 150 feet, you likely noticed the far edges of the returns
were dark. I put a diagram together for you to think about.
bright some thing shows up on the screen is determined by
its hardness, or reflectivity, and the angle the sonar wave
strikes it. If you've run your unit with it set to wide sides, say
over 150 feet, you likely noticed the far edges of the returns
were dark. I put a diagram together for you to think about.
It's my opinion that the amount of return is going to have a lot
to do with the angle the wave hits it. Like skipping a stone,
the more down it goes the more energy that radiates out, the
higher the angle, the more the energy goes forward away
from where it came. Thus smaller amounts for return signal.
to do with the angle the wave hits it. Like skipping a stone,
the more down it goes the more energy that radiates out, the
higher the angle, the more the energy goes forward away
from where it came. Thus smaller amounts for return signal.