Humminbird Side Imaging Forums

General => General Discussion => Topic started by: Rotus623 on July 01, 2013, 09:29:11 AM

Title: SI distance inaccurate?
Post by: Rotus623 on July 01, 2013, 09:29:11 AM

Hey fellas, I have noticed that the distance of my SI seems like it is not reaching as far as it is saying. If I stretch the beams out to 145', it seems like I am much closer to the shoreline before it will pick up the shoreline. Is there a chance that I am getting some distance distortion, or do I just have a really bad judge of distance?

Title: Re: SI distance inaccurate?
Post by: rnvinc on July 01, 2013, 11:43:36 AM

Robert explains this very well here...

http://forums.sideimagingsoft.com/index.php?topic=946.0 (http://forums.sideimagingsoft.com/index.php?topic=946.0)

Rickie

Title: Re: SI distance inaccurate?
Post by: Humminbird_Greg on July 02, 2013, 01:54:37 PM

The distance to the shoreline will not be affected by any slant range distortion.  If the shoreline is 145 feet away the Si unit should show the shoreline 145 feet away as this would be a horizontal distance measurement.

Title: Re: SI distance inaccurate?
Post by: Rotus623 on July 22, 2013, 12:58:31 PM

Thanks for the clarification Greg. I must have bad depth perception.  :D

Title: Re: SI distance inaccurate?
Post by: sjefsrafsern on August 17, 2013, 03:47:45 PM

hi, i run my planerboards 90 feet of to the sides and they show up close to the 90 foot range line on my si. so that is a good way to test it if you doubt your unit gives a correct reading. :)

Title: Re: SI distance inaccurate?
Post by: LittleGazoo on August 18, 2013, 01:04:16 PM

So when marking waypoints from SI in deep water, then the waypoint is off some?

Title: Re: SI distance inaccurate?
Post by: rnvinc on August 18, 2013, 02:15:52 PM

Quote from: LittleGazoo on August 18, 2013, 01:04:16 PM

So when marking waypoints from SI in deep water, then the waypoint is off some?

I mark my waypoints where the structure seems to intersect with the bottom...as the slant range measuring method to that specific point should be more accurate than any point marked higher in the structure...

Now marking suspended fish or bait balls would be a different story....because they don't intersect with the bottom detail...

Rickie

Title: Re: SI distance inaccurate?
Post by: RGecy on August 19, 2013, 07:03:52 PM

Quote from: LittleGazoo on August 18, 2013, 01:04:16 PM

So when marking waypoints from SI in deep water, then the waypoint is off some?

No, Humminbird has used the slant range calculation based on the water depth to correct this. 

Robert