Miscellaneous > Fishing

Grid set up for small lake- SAR Input requested


Hello all,  there is a small public lake nearby (3530'12.00" N  8615'00.00" W) that is only 1000 feet wide by 4000 feet long and water area is only 42 acres.  the average or maximum depth is about 30 feet gradually tapering to the upper end to about a foot.  It does have an irregular shoreline with only two coves of any significance.

I am thinking this is something the SAR guys do regularly so am asking for their input specifically.  Although it is not for SAR but for fishing I am thinking they will have the information I need.  I want to side scan the entire lake looking for out of the way fish attractors using the grid and way points. 

I am thinking of setting the scan width to 60 feet each side with the scan grid lines being 50 feet apart.  This will give me a 50% sidelap thereby resulting in double coverage of the entire bottom from 2 different perspectives (hmm, I wonder if you can see stereo since you will have two perspectives?).  Yeah, I did the math and its about 12 miles of scanning (taking out the irregular points).

I plan to run at 3mph with a chart speed of 3.  Then review this with a PC later and go back for detailed scan at 1mph of anything that looks interesting.  I think i can use the 17 foot tracker with the I-pilot and let it navigate for me.


997 for chart viewing and 998 for i-pilot and SI recording
scan tracks at 50 foot spacing
range set to 60 feet
3 mph
chart speed of 3
4 hours plus a little in time

Any suggestions?

Questions I need help with;
1. by the time I zoom in to get the grid spacing the way I want it it only covers a small area of the lake.  is there a way to generate parallel lines/waypoints that are 4000 feet long at the 50 foot spacing?

2. Any idea how much data I will be generating in MB?


Since the lake is average depth of 30', i would set the range to 90 or 100'.  If you are set to 60, half of your data is really just the water column.  Now, if most of the lake is average 10-15' and only a small portion is 30'. That may be ok.  I know this will be harder to see objects on the unit itself while scanning, but it you will be able to zoom in much better on playback and in the 3rd party viewers.  I would also do my initial run at 455khz and then go back with 800khz on objects of interest.    I wouldnt worryabout scanning at 1mph. At 3mph, the unit pings enough times to get a fantastic image of most anything you need to see.  I would just go back with 800khz!

I use a third party software to create my runs and then convert the waypoints to gpx to import, and then create a route with Humminbird.  You can do it manually as well.

I know there are some numbers here on the forum about how much data will be recorded per hour, but you may have to search to find it.

What i would do is make each run a seperate recording.  And of course HB automatically stores them sequentially by name. 

Then i would use one of the 3rd party programs to view or create a mosaic.


Thanks Robert.  Some good info to incorporate into the plan.  Will let you know how things work out.


I am piggy-backing on this thread because my first-time mapping project is similar to promapper's.  I want to cover a 2K x 3K foot area of a submerged townsite. I have already prepared a contour and 3D map with ReefMaster and identified the area. The depth ranges from 20 to 70 feet. Based on your recommendation to promapper, an SI range of 100-120, speed 3 mph, scroll 3, and a 50 foot grid should do the trick?

I would appreciate your input before I attempt this, as I would hate to have to do it over again!



[0] Message Index

Go to full version