Topic: Help with display on 998c SI

[newkid4si]

Unit= 998c SI
Display= SI @ 90'
Depth= 45'
Software= 5.410

Issue= Have located a boat on the bottom of the lake in 45 FOW.  Can pass directly over it ( SI )  with image split in half ( equal image right / left ) on screen. Boat is 18-20 foot speed boat. Same pass with 2D/ bottom lock shows nothing. Worked a grid ( 2D ) around location and may have found it about 50-75' away. 

?'s-- with display on SI @ 90'-- center of display is boat-- darker area in display is water under boat ( 0-45' deep ) (( shows up on screen at 45' left/right lines )) --- rest of display shows bottom from 45' out to 90'  How do you see what is directly under the boat-- 0-45' in SI, or can you? The reason I want the exact location is to drop an anchor/marker on it so the divers don't have to hunt all over the bottom.

Yes I have used DI and can see it on the display, but can't figure out which direction ( front/back/left/right ) it is.
Best guess is boat is 1-2' above the soft bottom. Boat shows up bright white in SI-DI image.

[96720]

If you’re trying to relocate the boat use the DI SI split screen and do a grid until the boat shows up on one side of the SI.  You can then determine the orientation and have and approximate bearing that the axis lies.  It would be easiest to split the boat at its width and more of it will show up as a visual on the SI.  What shows up on the SI directly under the boat is what you described “dark area in display is water under boat” and that point where it changes is the “bottom” directly under the boat.  But, remember its after the fact, you are trying to interpret a visual after you passed over it.  Your observations are right that the DI and SI do show bright “reflections” off of harder objects so you need to use it as a search tool.  Once you’ve marked your position on the GPS it should put you and the divers on the spot.

[newkid4si]

96720-- Thanks for the reply. You have some good info which I'll use.
             I remembered how to turn off the "water column" under the boat so that it will not be displayed.
             That should help.

             My goal is to be able to drop a marker on a target and when I tell the diver it's " right there "-- I'd like to be pretty close.
             
             

[stillbear]

Newkid4si  when i am searching an get a split image of a target on my screen i will throw a bouy behind my boat
i will circle around an stay around 40 feet from the bouy  when i start getting an image on my screen i will determine
weather to mark a waypoint or choose a different angle to take my shot. When you cursor over the boat and hit
mark you will have a waypoint and snapshot of the boat if you have your snapshots enabled and a SD card in your unit.
You will have no problem returning to the boat.  Gary

[newkid4si]

Gary-- Thanks for the reply. More good info.
           On my first target last week, I dropped the marker inside of the target.
           I thought I was pretty good. I've since demoted myself .....to pretty lucky.
           
           Spent the afternoon rereading the owners manual and found some other ideas.
           ie... change from " clear mode" ( less than 15 FOW ) to " max mode ( more than 15 FOW ).
           I'm working in 45'. That will help with the 2D display.    There's more, but it's late.

[sonar2000]

I remembered how to turn off the "water column" under the boat so that it will not be displayed.
             That should help.

Newkid......would you like to post how you turned off the water column so that others who want to do the same will know...

I would do it but since you posted you can take the credit...(always like to promote the users here on the forum)

Chuck