FishFinder Range

[izuizme]

Last year I got my 2nd boat and got an Eagle silver striker 600 + fishfinder.Then I ordered the speed/temp sensor that was availible,and it works just fine.<br />Question is when I look at the display screen how can I tell how far away from the back of the boat things displayed on the screen are ? The screen is about 4" wide.

 

[DuPont Spinner]

Re: FishFinder Range

Well now...it all depends on if your boat is moving or not. If you are sitting still, what you see show up on the right side of the screen will always be under your boat. The image on the screen will scroll to the left in order to make room for new imagery. Keep in mind that only current information is displayed on the very right edge of the screen. Anything to the left is history. As you can imagine, when the boat starts to move forward, not only will you add history to the screen, now you have put distance between you and the last update that shows up on the screen. The faster you move, the greater the distance. There is also the cone angle of the transducer to take into consideration as well as the various depths which you are traveling over. I guess the bottom line to your question is that there are so many variables to take into account that it may be extemely difficult to come to a close figure. Hopefully someone with more knowledge can help as it appears I havn't been much.

 

[jimchere]

Re: FishFinder Range

Not exact but close enough perhaps? This stuff happens fast so lots of rounding. Anways, the speed of sound varies in water dependent on depth, salinity, temp, etc. But a good average is 5000 feet per second. So, if the water is 100 feet deep, then the sound travels 200 feet (from your xducer, to the bottom, then back up). That means the sound time is approx 0.04 second (4/100 of a second). Be generous and allot 0.06 second for processor time in the unit, and we round it up and that means the data you look at on the right edge of the screen is say about .1 (or one tenth of a second) old. If you are moving at say 33 miles/hour, that is about 44 feet/second. That means the data at the right edge of your screen would be about 4 feet behind you. Now, that doesn't include human mental processing time

 

[ericgj510]

Re: FishFinder Range

jimchere,<br /><br />Are you sure?

 

[jimchere]

Re: FishFinder Range

Pretty sure about all the numbers and conversions except the processor time, which is a guess that is probably pessimistic. In the end, what I tried to show was that the result is pretty insignificant.<br />On a side note, you can't completely rely on a depthfinder to keep you from running aground because it tells you where you're already at! Any other opinions?