11-18-2005, 12:58 PM
Hey Micheal,
You should regisiter and become a BFT member.
Anyway, I have a Fishing Buddy(older model 2255) with 360 * side finder, water temp, and navigational compass. It's a sweet unit, but it does have some limitations. As you noted it has a rather small 9* cone. But on the good side, that 9* cone has a much smaller blind spot as compared to finders with larger cones - like my other fishfinder that has a 90 * cone.
The good thing about a large cone is what it can show you that is higher in the water column - you can see more suspended fish because of the greater cone size.
The down side to the larger cone is looking at the bottom and the size of the potential blindspot there.
The good thing about a small cone is you can see more on the bottom because of the smaller blind spot. The down side to the small cone is the overall coverage in the water column.
The blind spot on a fishfinder is evident when passing over structure or slopes, and can be very limiting while anchored or stationary. In other words, you could see more with a small cone than a large cone in those situations.
Let me try to explain this if I can(I'll leave out the tedious math parts and techy talk). All transducers read from the nearest point. On flat even bottoms, a wide cone can cover more area than a small cone. On a drop off or over any structure, a sonar's cone will be measured and displayed from the point nearest to the transducer or the top of the drop off or top of the structure. If the nearest point is straight down, there will be a blind spot around the edge of the cone.
Example: Let's say you're drift fishing along a smooth flat area(assume no rocks or any structure) with your 60* cone(I'm only using 60* because there is mathmatical correspondence of about a 1 to 1 depth to cone size ratio) on the bottom in 10 feet of water. You would be looking at a circle on the bottom that is roughly 10 feet in diameter - the nearest point to the transducer would be directly under you(in a straight line). Then, you slowly drift over a drop-off that goes down at a 45* angle from 10 feet to 40 feet in depth and drop anchor at a point that is exactly 5 ft from the top edge of the drop-off - so that only the very edge of the cone is now still at the 10 foot depth level. Now the nearest point to the transducer is at the edge of the cone that hasn't gone over the drop-off yet - everything else is in your blind spot. You now that a 10 foot diameter cone that is no longer on the bottom and eveything(like fish) under it is not going to be displayed because it's in the finders blind spot. That's a bummer because lots of fish like to hang out right in that kind of area.
Example 2: You are trolling along a 10 foot deep smooth flat area with your 60* cone that displays a 10 foot circle on the bottom. You come across a rock that is 3 feet in diameter - the second that the rock enters the edge of the cone(the rock will be 5 ft away still), your depth reads 7 feet(you havent even gone over the rock yet) and every thing that is on the bottom( below the 7 feet on your display) disappears from your screen. That's bad because fish hang out next to structure(rocks and such). At the moment your cone hit the rock and untill the moment your cone completely passes the rock your blind spot is everything under the top of the rock(in essence, you have a blindspot that is about the size of your entire cone from the top of the rock all the way to the bottom) - That unfortuanately, is exactly where the fish would be holding and you would never see them.
There are advantages to both large coverage transducers and small coverage transducers. You type of fishing will determine which will work best for you. I have both.
I hope that was understandable - if not, feel free to ask. I realize my description might not have been well presented. I might try to work up some graphics to make this more easily understandable - I have been asked to explain this on a number of occasions and I don't think I've ever done it that well. You know - a picture can be better than a thousand words.
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You should regisiter and become a BFT member.
Anyway, I have a Fishing Buddy(older model 2255) with 360 * side finder, water temp, and navigational compass. It's a sweet unit, but it does have some limitations. As you noted it has a rather small 9* cone. But on the good side, that 9* cone has a much smaller blind spot as compared to finders with larger cones - like my other fishfinder that has a 90 * cone.
The good thing about a large cone is what it can show you that is higher in the water column - you can see more suspended fish because of the greater cone size.
The down side to the larger cone is looking at the bottom and the size of the potential blindspot there.
The good thing about a small cone is you can see more on the bottom because of the smaller blind spot. The down side to the small cone is the overall coverage in the water column.
The blind spot on a fishfinder is evident when passing over structure or slopes, and can be very limiting while anchored or stationary. In other words, you could see more with a small cone than a large cone in those situations.
Let me try to explain this if I can(I'll leave out the tedious math parts and techy talk). All transducers read from the nearest point. On flat even bottoms, a wide cone can cover more area than a small cone. On a drop off or over any structure, a sonar's cone will be measured and displayed from the point nearest to the transducer or the top of the drop off or top of the structure. If the nearest point is straight down, there will be a blind spot around the edge of the cone.
Example: Let's say you're drift fishing along a smooth flat area(assume no rocks or any structure) with your 60* cone(I'm only using 60* because there is mathmatical correspondence of about a 1 to 1 depth to cone size ratio) on the bottom in 10 feet of water. You would be looking at a circle on the bottom that is roughly 10 feet in diameter - the nearest point to the transducer would be directly under you(in a straight line). Then, you slowly drift over a drop-off that goes down at a 45* angle from 10 feet to 40 feet in depth and drop anchor at a point that is exactly 5 ft from the top edge of the drop-off - so that only the very edge of the cone is now still at the 10 foot depth level. Now the nearest point to the transducer is at the edge of the cone that hasn't gone over the drop-off yet - everything else is in your blind spot. You now that a 10 foot diameter cone that is no longer on the bottom and eveything(like fish) under it is not going to be displayed because it's in the finders blind spot. That's a bummer because lots of fish like to hang out right in that kind of area.
Example 2: You are trolling along a 10 foot deep smooth flat area with your 60* cone that displays a 10 foot circle on the bottom. You come across a rock that is 3 feet in diameter - the second that the rock enters the edge of the cone(the rock will be 5 ft away still), your depth reads 7 feet(you havent even gone over the rock yet) and every thing that is on the bottom( below the 7 feet on your display) disappears from your screen. That's bad because fish hang out next to structure(rocks and such). At the moment your cone hit the rock and untill the moment your cone completely passes the rock your blind spot is everything under the top of the rock(in essence, you have a blindspot that is about the size of your entire cone from the top of the rock all the way to the bottom) - That unfortuanately, is exactly where the fish would be holding and you would never see them.
There are advantages to both large coverage transducers and small coverage transducers. You type of fishing will determine which will work best for you. I have both.
I hope that was understandable - if not, feel free to ask. I realize my description might not have been well presented. I might try to work up some graphics to make this more easily understandable - I have been asked to explain this on a number of occasions and I don't think I've ever done it that well. You know - a picture can be better than a thousand words.
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