In this video I did from a recent trip to the lake with my Humminbird Onix 10 SI, I was scanning the lake for Eel Grass. I’ll explain to you what Eel Grass looks like and what to look for when scanning the lake bottom for it.
In an earlier blog I wrote about needing Side image to get the most out of your Down Image scanning. In this blog I’ll show you an example when you needed Down Image to find the structure that is hard to see with the Side Imaging transducer. In this scan I am using my Humminbird Onix 10 Touch SI/DI unit. Then as usual I convert the recordings using ReefMaster Sonar Viewer software. In this blog I will only be posting three images and you can see why you still need both your Side Imaging and down Imaging transducer at the same time in most cases.
In most instances I use only my Side Imaging while scanning for structure and I use my Down Imaging to try and locate fish whether it’s bass, crappie, white bass or any other species of fish i might be after on that trip. When I’m scanning for structure with my Side Image I usually have my unit scanning out to 100 feet on each side. If I’m looking for fish with my Side Image and Down Image together I set the Side image range to either 50 or 60 feet. On my Side image I use the 455 kHz and on the Down Image I set it up to use the 800 kHz settings. This will usually give me the clearest images i have found on my units.
The color palette will be a matter of personal preference. On my Onix for example before all the software updates I liked to use the “Green” palette but with the last software update I find myself using the #2 “Amber” palette the most. On my 360 transducer in shallow water I like the “Gray” palette the best. As usual you will have the continually make changes on the fly with your “Sensitivity” and your “Contrast” setting during the scanning process.
Okay now for my first image from a recent scan I did on the water. I,n the image below you can see a lot of stuff in the water, there are lots of schools of bait-fish. You can see some larger fish near the bottom which could be catfish or Asian Carp. You can the edge on the old creek channel bank on the right side of the image. You can see some larger fish up in the water column under the bait-fish which could be bass, stripe or crappie. You can see what looks to be a tree limb on the lower left of the image and possibly a brush top almost in the center of the screen.
Now in the next image I am using the Down Image transducer to run the exact as area, as a matter of fact I was running both the Side Image and the Down Image at the same time to get this scan. But you can now see what I missed with just the Side Image transducer.
Wow, now what do you see in the Down Image scan? You can now clearly see the three big man-made brush tops someone dropped in the lake! You can still see the bait-fish and a few fish but not everything you saw in the Side Image scan image.
And finally in this last image I’l show you them side by side and see what you can and can’t see if you were only running one without the other.
Remember I was running both at the same time over the exact same area and I would have missed the three big brush tops without having them both on at the same time. So you can clearly see you need to run both at the same time to get the most out of your units. This is one reason you need the larger units like the 10″ or 12″ for the largest screen area you can see at once. I also run a Helix 12 SI Mega but most of the time I only use it for mapping as i find my Onix unit gives me the clearest image of the both of them.
I hope you get a little more understanding out of your expense tools you have added to you boat.
In my last blog I showed you a software program I used on how I manage my waypoints and allows me to see where they are along with the contour lines on a lake map. But as you may have noticed the contour lines were listed in “Meters” instead of feet. But you are able to change it to feet if you prefer to use them instead. You will need to be a little computer savvy to make this change but you should be able to do it by following the following steps.
First thing is to make sure the SAS Planet program is closed. Now you will need to find the “Folder” where you installed the program.
Next, we need to “Open” the folder by double clicking on the folder. After you have the folder open you will now need to open the next folder. This will be labeled as “Maps” double click on this folder.
The next folder we need to open is the”_water”” folder. Move your mouse over the folder and double click to open the folder.
Then next folder that we need tot open is the “SAS.plus.maps” folder. Double click on this folder to open it.
Now we need to open the “navionics.layer.zmp” folder to make the changes required to change the meters to feet settings.
Now inside this folder you will find a file by the name of “GetUrlScript.txt” this is the text file we need to edit to change the program from “Meters” to “Feet”. Double click on the file and it will open in the Windows “Notepad” program.
Look at the line I have high-lighted and you will see a red circle with a number “1” in it. To make the change all we have to do is change the “1” to a “2”.
After you edit the number all we need to do is “Save” the file. DO NOT rename the file or “Save As” or move the file! Just select “Save” and close the “Notepad” program. See photo below.
Now that you have made the change to that file, we need to do the same thing to three more files. Just repeat the same steps in the three following folders.
After you have edited all four files then you can open the SASPlanet program and you should see the depth contour lines are now in “Feet” and not “Meters”.
Hope you enjoy the SAS Planet program as I do in managing all your hundreds or thousands of waypoints.
Do you want to get the most out of your GPS units and managing all your way points as I do? If you have thousands of way points and have a hard time keeping them organized then you should take a look at downloading a software program which is free by the way called “SASPlanet” or type in this link in your browser where you can download the software. (http://www.sasgis.org/download/)
As of this blog the latest version released is 181221 but they are continually releasing newer version but this is the one that I personally use. Notice at the top of the web page that you will need to change the translation from Russian to English. In the second red oval in the photo is the link to download the software. By way you do NOT have to provide any personal information to download the software.
From the download link just download and make sure you know your download files location which is usually the “Download” folder on your computer.
After you have downloaded the software you will need to un-compress the file as it is in “.zip” format which should already be on your computer. If not you should be able to find it on the web with a browser search for WinZip.
Now that you have downloaded and installed the software let me show you how helpful it will be to you. When you first launch the software program a screen should pop up similar to this one, if not just move your mouse around and zoom in or out to your area or lake you fish.
In the photo below I have zoomed in and selected a lake at random which I’ll use in this blog, at the present time I do not know where or what lake this is. But as this is only an example you can simply zoom in on your lake that you fish or want information about. Now we need to make a few adjustments in the setting of the software.
When you zoom in on the map you should get a view like the one below. But we need to change it since we want to use it for our GPS way points.
Now let’s make the necessary adjustments to may the software do what we want to use it for. How we do this is to make a change in the type of map we want to use. On the Menu bar you should see the option to change the map as shown in the photo below. From the drop-down maps options you want to select “Marine maps”, then select “Navionics Marine Charts” do not select “Navionics SonarCharts™.
Now as you can see in the photo below the background as well as the water has now changed to a map with depth contour lines. NOTE: The depths are shown as “Meters” and not “Feet” in another blog I’ll show you how to change the meters to feet settings.
Now if you Zoom in on the map you can see the contour lines for the lake and areas of the lake you want to explore.
Now let’s play around with the map and create a few way points by just looking at the map of the lake as we move around it. Okay let’s say we see a spot we would like to create a way point on, then do the following as in the photo below.
You can place your mouse cursor over say a point, hump, flat and anywhere you want a way point. Select “Add Placemark” And once you do the following menu box will pop up allowing you to make some adjustments to the waypoint you will create.
Under the “Category” I rename this to the Lake or area of the lake I want the way points on. Next under “Name” give the waypoint a name up to eleven letters or numbers. (Any more than eleven you will get an error message when you try to convert them in Humminbird PC). Under the “Geographic Coordinates” you can make changes if necessary. In a few paragraph’s I’ll show you how to change the coordinates types that we normally will use in our units. Next under the “Descriptions” box you can write notes applying to the waypoints. On the “Text color” option I select “Red” as it shows up better on the map background. After you make these changes hit the “OK” button.
After you hit “OK” the next box that will pop up will be the “Placement Manager” menu. Here you will see the Category and list of waypoints you created. But you will have the option to Import your current way points or share them from or with your buddies.
Okay let’s say we have way points that we want to “Edit” your way points. Select the Way point from the list and we can make those edits, lake name, way point name, coordinates and notes as we notes above.
Here you see I make the edits I wanted for this waypoint. Note: These are fictious way points as I have never fished Broken Bow and the notes are for example only.
Next I’ll show you how to change the coordinates to the type we normally use. Across the top Menu bar select “Settings” then “Options”.
From the Menu taps select “View” and the select the drop-down options on the way point coordinates types.
Select the one I have the arrow on or “WS deg.min.” This option will add an extra number on the last number for example “1234” just change the “4” to a “0” so it will look like “1230”.
After you have finished editing or creating your waypoints you now have the option to export them to a “GPX” file which you can convert them to any “GPS” coordinates you need. You can convert them in Humminbird PC to work in your Helix, Onyx or Solix units. You can convert them to use in Lowrance or Garmin units with GPS Babel for example. You export them by selecting the “Category” name the press your Right Mouse button. The Export Placemarks menu will pop up.
The program will try to save them as a “.kmz” format but you need to select the drop-down menu and select “.gpx” instead.
Now let me show you how to “Import” your current waypoints you may already have. If they are on your unit or units you will need to get them on an SD card and then copy them to your computer. If they are from Helix, Garmin or Lowrance units you can convert them to “GPX” format with Humminbird PC. From the “Operations” Menu select “Open” and then you will be prompted for the waypoint file location which could be the SD card if they are in “GPX” format.
Select the waypoint file and select “Open” to import them into the program.
Note if you already have the “Placemark Manager” open you can “Import” them by selecting the “Import” button at the bottom right on the box.
When you select the “Open” then the file you will get the following menu options in the photo below. Here you can rename the waypoint file to anything you want. For an example let’s say you have two units on your boat and have waypoints on both of them that are not linked. Save one file as say “Rear Unit” and the other one as “Bow Unit”. That way you know which waypoints are on which unit. You can compare the waypoints on both units and add or delete the ones that are duplicates, bad ones, old ones or anything else you might want to do with them. One thing I do is change the “Icons” for each file so I know which file is on which unit. When finished with your “Edits” select “Start” on the bottom.
After you make your edits and select “Start” the next screen will look like this now just select “Yes” to import the waypoints.
Now to see the waypoints you imported you must select the “Placemark Manager”. In the top menu bar select it, the one in the red circle in the photo below.
Now we can view our waypoints by placing a “Check” mark in the “Categories” waypoint list.
Now you can see all your waypoints on the map.
Hope you found this helpful and hope this helps you manage all your waypoints.
I seen a post on Facebook the other day about “Do You Really Use Your Depth Finder To Help You Catch Fish”? That is a really good question, as I have seen a buddy that I fished with that had a new Garmin Depth Finder on his boat but never turned it on while we were fishing. In his case I think it was all about having the “Newest Thing” on his boat. It’s the same as having Power Poles® on your boat but never put them down. If you’re going to pay out the money for the newest technology then you need to take the time to learn to use them. I personally have six units on my boat but actually only use three or four of them at a time. Two of the units were small in-dash depth finders that came with the boat.
One thing I had a hard time understanding when I first got my first depth finder an old “Super Sixty” flasher that I used to catch a lot of fish watching it. I could watch my jigging spoon go up and down as I lifted and lowered my rod and see the fish signals come to the spoon while watching the flasher. Now that we have the choices of Side Imaging, Down Imaging and Sonar all in the same units they have really become a big help in catching fish whether it be bass, crappie, bluegill or white bass.
As we ride around the lake or body of water you are fishing looking at things that pop up on the screen and wonder what they are. To learn this, we must both spend the time on the water learning our units and to actually know what they are that we’re looking for. Here is a screen shot of something on the bottom that my boat passed over. One what is it and second where is it in relation to the boat and where do I need to make my cast to make contact with the structure?
Okay take a look at the photo above and see if you can tell, first what is it, and second where is it and third where do I cast to so I can try and catch any fish that may be located in the structure. Just by looking at the photo above, I first thought it was directly under the boat which in this case part of it is but most is not. If it is under the boat where under the boat is it located? I would in the past make a cast straight behind the boat to try and make contact with the structure. Sometimes I would make contact with the structure but most of the time I did not. The one way we can tell that part of the structure is partially under the boat is the red coloring in the screen shot in the brush top. This red color tells me that the strongest signals are in the very center of the sonar cone. Take a look at the photo below to get a better understanding of what this means.
Now let’s take a look at the same piece of structure with our Down Image unit and see if we can see what it is and where it is.
Okay we can tell that it looks to be a brush top someone placed in the lake and there looks to be one fish on the right side of the brush top on the right at the edge of the screen. By looking at the fish and the shape it could possibly be a crappie as it is tall as it is long. But this is only a guess and we have no way of knowing unless we actually catch the fish.
Okay so now we know it is possibly a brush top but where is it. Well again since I thought I drove over the structure you’d think it is behind the boat. But again, it could be but also could not be under and behind the boat.
Now let’s see what the structure actually is and where it is in relationship to the boat. We can determine all this by using our Side Image unit. Not only will it tell us what it is but where it is located and where we need to make our cast to try and catch that fish that we are after.
Okay from the side image view we can tell that it is actually a brush top under the boat and also a bucket with what looks to be canes by seeing the shadows of the canes. And last a huge stump to the right of the boat about 20 feet to the right of the boat. By the way can you find the fish in this screen shot? Hint look for the shadows they give the fish away.
In this last screen shot I did with third party software available to you the angler you can see the location of the structure.
So, to get the best out of your new or current units you have to use the tools you have and learn to use them to help you catch more fish. After all this is the reason, we spent the hundreds of dollars if not thousands of dollars on the “Newest Thing” for our boats.
Definition of thermocline
: the region in a thermally stratified body of water which separates warmer surface water from cold deep water and in which temperature decreases rapidly with depth.
The thermocline is formed on lakes with little to no current flow that allows the mixing of the top and bottom layers of the lake waters. Since cold air and water is heavier that warm or hot air or water the heavier sinks and the warmer rises. In the following three images you can clear see the thermocline. Summer and early fall is the times that the thermocline is most prevalent with the high air temperatures this time of the year.
Why knowing where the thermocline is important to you as a fisherman? Simple it will define the maximum depth you need to be fishing. The thermocline is void of life giving oxygen so the fish you are seeking can not live in the thermocline. During the summer and early fall, adjust your unit to see the thermocline. Scan the area you are planning to fish and look for the top of the thermocline. Let’s say the top is at 27 feet as in the images in this blog. Then the maximum depth you need to fish is no deeper that 27 feet. Look for a or drop-off, shell mound or hump that is shallower than 27 feet and fish there if you see fish on them with your down image units.
Finding the thermocline is easy with the new Side Image and Down Image sonar units, in my case I use the Humminbird Onix 10 SI and the Helix 12 Gen2 Mega Scan. You will need to learn to adjust the sensitivity and contrast settings. You can find settings on this blog just do a search in the search bar. There are a lot of YouTube videos on how to tune your units.
Hope you find this blog helpful in understanding the thermocline in your fishing.
In my last blog I talked bout the Benjamin Marauder .25 PCP air rifle. In this blog I’ll talk about another one of my guns. This one is the Hatsan BT65 QE which is made in Turkey. This gun is not is a toy and is bit on the heavy side of air rifles weighing in at 9.3 pounds and is 48.9” in length. As of this writing the price for the gun on the internet is $679.00 for the stock gun without any accessories. The Hatsan BT65 QE comes with a 1-year Limited warranty.
The BT65 QE stands for QuiteEnergy which is a fully shrouded barrel with a simple baffling system which is said to reduce the noise by 50%. This said I will say that this is the loudest gun I own in the PCP air rifles.
There are suppressors on the internet that you can purchase to quieting down the gun but I have not purchased one for my gun yet. The above photo is just one option I found on the internet.
The stock on my gun is synthetic but you can buy the gun with a wood stock if you prefer. Since I use my guns for plinking and hunting I opted for the plastic stock. The stock is ambidextrous and has an integrated picatinny rail beneath the forearm. The rail is not very good so I opted to cut mine off and added metal one to secure my 6 to 9 inch bipod instead.
The gun comes with two nine shot rotating magazines that are smooth working but is difficult to figure out the last pellet unless you count them as you shoot. This was not a good design in my opinion. One thing you need to do when loading the magazines is to seat the pellets. Push them in and then take a pencil or something to press them down into the magazine. There are two rubber O-rings that will hold the pellets in place and they are very secure. One thing about this gun is that each time you cock it the Safety is automatically engaged, but is close to your thumb and easy to move to Fire.
The gun has a detachable aluminum air cylinder tube (255cc) to hold the 200 Bar high pressure air and with my tweaked will be about 20 accurate shots between fills. I also purchased a spare cylinder for my gun that I installed a HUMA regulator into. The gun comes with a quick-fill nozzle and air cylinder discharging cap supplied. At full fill of around 200 Bars or 2900 psi the manufacture say you will get 27 shots at 1097 fps. Mine is set with my HUMA regulator to 915 fps and about 20 good shots as stated before.
The gun has a dovetail groove receiver for both 11mm and 22mm scope mounts.
I have a Hawke Sidewinder 30 SF IR 6-24×56 AO, SR Pro Reticle scope in 30 mm. But you can use any good quality scope on this gun as a PCP does not have any recoil.
The gun comes with what they say is an “Anti-double pellet feed” mechanism preventing more than one pellet loading into barrel. But I have loaded double pellets in my gun several times without knowing it. The gun also comes with a Sling and a cheap bipod.
Quattro Trigger: 2-stage full adjustable match trigger for trigger travel and trigger load. Gold plated metal trigger & metal trigger guard. I have mine set to about 2 pounds of pull which is very light.
How accurate is my gun, take a look at the photos below for groups done when the outside temperature was 57* 30.03 in pressure 84% humidity and a 8 mph SSE wind at 25, 50 and out to 75 yards.
As you can tell this is a very accurate PCP air rifle and I was going to shoot it out to 100 yards today but it was just too windy. The gun is much more accurate than this 64 year old shooter is able to shoot. These shot groups were off a bench with the guns bipod and a rear sand bag. With a good vise the groups would be in the .500” center to center or less out to 50 yards for sure.
Hope you found this blog interested and I’’ do a couple more on my other two guns when I find the time. Thanks again for reading my blog.
If you’re looking for an air rifle for either plinking or for hunting that is a very accurate air rifle then you need to take a look at the Benjamin Marauder. This air rifle is not a toy gun but a very hard hitting accurate gun that is both fun and cheap to shoot. The Benjamin comes in .177, .22 and .25 calibers. I personally own the .25 caliber. There is a ton of information on the gun as far as reviews on the internet. What I’ll be doing in this blog will be talking about my gun and the modifications I have made to the gun to improve its accuracy. The Marauder is an unregulated pcp but Benjamin now has a regulated model available at the time I bought mine they did not offer the regulated rifle.
The Benjamin I purchased was ordered from Pyramyd Air for the synthetic model for around $530 dollars. I also bought a Hawke Vantage 4x16x50 scope $209, a CVlife Bipod to start out with. Since I’ve had the gun I’ve made a few modifications to the gun and shot a lot of different pellet weights and brands to determine which pellet if likes the best. I also added some camouflage tape to the stock and barrel since I use it for squirrel hunting as well as target practice.
I need to mention that this gun is a PCP or pre-charged pneumatic gun that means it shoots with high pressure air up to 3000 psi. There are a few ways you can charge or air up the gun, a hand pump which I purchased when I bought the gun. The hand pump is very labor intensive to pump 3000 psi into the gun! From a 0 psi up to 3000 psi took me 175 strokes which took me about 30 minutes to do! The other way is to buy a scuba tank or SCBA tank that can be filled at a paintball shop or from a compressor you can buy (but very expensive). There is also the option of using a nitrogen tank which can be rented from a welding supply shop.
The next thing will be ammo in the form of pellets. There are a ton of options on pellets out there. Crossman, JSB, H&N and Air Arms are a few of the brands I use. Every air rifle will shoot a little different and accuracy is achieved by finding the right pellet for your barrel on your gun and the right air pressure you are trying to get to. My gun likes the JSB Exact Diabolo 25.39 grain and the Crossman Domed 27.8 grains the best. Since the barrels on the Marauder has a rifled barrel pellets the gun is very accurate with the right pellet. My gun current as of this writing will consistently shoot .750” five shot groups at 40 yards. This gun with the right pressure and pellet setting will shoot 2” or better groups out to 100 yards.
Without any modifications the gun is still accurate but with modifications you can get better accuracy and more shots on a single air fill than without the modifications. Another thing I need to let you know up front is that air gunning is a very addictive and expensive hobby! But hey, aren’t all our hobbies expensive?
I added a HUMA regulator to the Marauder which cost me around $110 plus shipping. What the HUMA does for the gun is to regulate the amount of air the gun uses for each shot. This will allow you better accuracy and more shots per fill as the amount of air used to push the pellet through the barrel is the same or almost the same every shot. With out the regulator the gun use different amounts of air for each shot and the pressure will drop fast on each shot. The HUMA regulator can be adjusted to the amount of pressure you want, less for more shots and higher for harder hitting shots but with a loss of the number of shots you will get on a fill. I went from getting about 10 to 12 shots to now around 30 to 35 shots after I installed the regulator per fill.
The next modification I did was drilling out the transfer port on both the rifle barrel and the valve in the gun. The transfer port is a small tube that connects the valve (where the air is stored from the regulator or without the regulator) that the air goes through to push the pellet down the barrel on each shot. The factory transfer port hole size is a little over .125” but I drilled mine out to .187” which lets the air out of the valve much faster. Take a straw blow through it and then blow out air without the straw and you’ll see the air from your mouth comes out much faster. This is what drilling out the transfer port does.
The next modification I did was replacing the stock Hammer spring with a Jefferson State Air Rifles TSS or a double spring system. What this does is, when you pull the trigger there is spring behind the hammer. This hammer strikes the valve poppet that lets the air out the valve up the transfer port and pushes the pellet down the barrel. What happens is that the hammer strikes the poppet pin and the spring bounces back and forth on the poppet several times before it settles down. When this happens each time the hammer bounces on the poppet pin it releases a small amount of high pressure air out of the fill tube. This will greatly reduce the number of shots you will get from a fill. By replacing the hammer spring with the TSS, the hammer will not strike the hammer again after the first strike thus saving air in the tube resulting in more shots; the cost of the TSS was around $80 plus shipping. So as you see tweaking and modifying your gun can get expensive or you can leave it alone and just shoot it the was it comes from the factory. To me it’s like having a muscle car from the factory and not doing upgrades to make it better!
Final thoughts, so as you can see there is a lot you can do with a PCP air rifle. Check out the many options of guns out there, they range in prices from $200 up to $2000 dollars! But at about $16 for a box of 500 pellets this is a very cheap way to practice compared to the cost of rim fire or center fire rifles. So have fun and I hope this opens your eyes to PCP air guns.
Thanks for checking out my blog articles.
Wilson Lake, Florence, Alabama.
When Wilson Lake was impounded there was a lot of old structures, canal, bridges and other structure let on the lake floor. With the advent of the new sonar technology such as Side Imaging and Down Imaging you can still find a lot of them.
I have both Humminbird Onix and Helix Mega Scan units on my boat. These amazing pieces of technology enable me to see what’s still laying on the ;lake floor to this day almost a 100 years later!
A Little History on the Lake
Wilson Dam spans the Tennessee River between Florence (north) and Muscle Shoals (south), Alabama. It stands at an elevation of 508 feet and crosses the Tennessee on a 20-foot roadway along the top of the dam. Impoundment of the Tennessee River above Wilson Dam has created Wilson Lake, with a maximum width of 1.6 miles and a main shoreline of 154 miles.
Wilson Dam was erected by the Army Corps of Engineers in 1918-25 and turned over to the Tennessee Valley Authority when that agency was established in 1933. Wilson is a concrete gravity-dam on a blue limestone rock foundation. The total length of the structure is 4,535 feet, the height 137 feet, and the maximum width at the base (Including the apron) is 160 feet. The head the water depth on the upper side of the dam is 97.6 feet. There were originally 58 spillway gates in the face of the dam, each capable of discharging 10,000 cubic feet of water per second.
As I scan the lake bottom with my Side Image and Down Image units I’m always looking for objects that are on the lake bottom. If I do manage to find something, if I can I’ll research and see if I can find out what it is and if possible try to find a photo of what the object is or was. In the two photos below I found an old submerged arched bridge crossing a small stream or creek bed. You can clearly see the creek bed in the Side Image photo.
Click on the photo thumbnails to get a larger view.
I found an old submerged mill a couple of years ago that an old time fisherman told me if I had ever looked for it. In the two photos below you can see what the mill looked like before it was torn down and all that was left was the stone work of the mill.
The following photo is an old marina boat cover slips that instead of being torn down was easier to just pull it out into the lake and sink it. The tin metal top and sides are still on the old boat cover slips. I have tried to find a photo of the original one but have not been able to do so.
In this blog I’ll be discussing Side Imaging Sonar and Down Imaging and do you need it. As I discussed in my earlier blog on Sonar versus Down Imaging was it really needed. From the images I’ll post below we can see that some of the structure is visible in the Sonar and the Down Image views but the problem is where they are located in relation to the boat.
As stated in the earlier blog I will be converting recordings done with my Humminbird Onix 10 SI Touch and my Helix 12 Gen 2 Mega Scan SI units. The software I use to view the recording is ReefMaster Viewer and sometime I will use Deepview FV as well as AutoChart Pro. Three of these are purchased software and the other one is a free software version. You can do a Google search to find out more on these products. As for recording with your Humminbird unit I have a blog discussing this as well just follow this link “Recording”.
The problem with Sonar and Down Imaging while fishing or even scanning the lake bottom with your units. Is to determine where the structure is in relation to your boat. Since we are dealing with a 2 dimensional flat screen and scanning a 3 dimensional world. Since the software on the units is only placing pixel dots on the screen there is no way to show the bottom in a real world display. That is unless we are using Side Imaging.
With Sonar and Down Imaging as we drive over the structure is it under the boat as the display shows? It possibly could be and we can tell this with the Sonar view by looking at the colors displayed on the screen palette. Since on a Sonar transducer set to 200 kHz the cone angle is pointing straight down and for an example shining like a flashlight beam. Take a flashlight and turn it on and point it straight down at the floor. The circle of light you see will represent the transducers cone angle. As you can see the angle is in a circular pattern and any object that enters the cone will be visible. Now lower the flashlight down towards the floor and you will see the circle of light gets smaller. This represents the depth of the water your boat is setting in. With a standard 200 kHz transducer the circle will be 1/3 of the depth of the water, for example in nine feet of water you will only be scanning a three foot circle of the bottom. Now move out into 30 feet of water and now you will be looking at a ten foot circle of the bottom.
With all that being said if your boat is in 9 feet of water and you drive your boat over say a stump, and it shows up on the display screen then that stump is directly under the boat. That is under the transducer where ever it is located.
Now let’s say we dropped a waypoint on that stump and wanted to fish it. As we turn the boat around and go back to the waypoint where is the stump in relation to the boat. Again on the display as we get closer to it it will show up on the display but now is it under the boat or in front, rear or right or left of the boat?
The only true way to know for sure is either with the Side Image or the Humminbird 360* transducer. With the Side Image transducer the problem is we now have to drive past the stump to see it displayed on the unit. But now we will know if the stump is on the right side or the left side of the boat. With the Humminbird 360* transducer we can see the stump without having to even move the boat. If the stump is at a three o’clock position we just cast to the stump at a 90* angle to find the stump.
I hope this explains a little the advantage of the Side Image transducer. Take a look at the images below to see what I am trying to explain. I’ll do a blog on the Humminbird 360* transducer after I get on the water and do some screen shots with it.
Click on the Thumbnails for an Enlarged view of the images.
In this image we can see a stump displayed on the Sonar but only know it is located slightly to the right of the boat by looking at the Side Image view. In this view we see the top is directly under the boat and slightly behind the boat.
Now let’s look at this gravel point that is off the the right side of the boat. Without the Side Image view we would not even know it was there.Can you see the gravel bar on both sides of the boat in the Down Image view.
See the tree top slightly to the left side but still under the boat?Stump field to the right and a stake-bed to the left not visible on the Down Image view.