Topic: A little confusion on my GPS. Help

[Dieago]

OK when I'm side imaging and I see structure and I put the courser on it and hit go to. when the alarm goes off is the structure suppose to be directly under my head unit? or when I approach a way point that I marked where I placed structure and set a way point and alarm goes off is the structure again directly under? I'm  having a hard time relocating placed structure and piles found on side scan. Any help would be greatly appreciated.

[LocDown]

How far away is your transducer from your screen? I am guessing you are using a 999 unit. You will have to add that distance and the gps accuracy distance to where you waypoint is/should be, if you're not using an external gps receiver.

[Dieago]

Yes its 6' away ang I have not set the offset in settings This is why I said under the head unit Ive been looking for it directly under where the Head unit sits (or screen). but also wondering when the arrival alarm sounds is it calling a 12ft circle + or- the spot? and sounding on outer circle? so my unit not transducer is 3ft from boat edge to my right so when it says Im over brush after cursoring and going to waypoint the little boat icon is moving towards spot when blue boat icon on map first touches blue circle of waypoint is brush under bow at that instance or in center of boat? or when boat icon has blue waypoint circle in center of boat is bruch or object under dead center of boat?
I know that if I enter coordinates into my unit and create a way point on the lake and go there upon arrival I can be + or - 6-8-10 foot away from actual spot where I have structure sank in lake. but lets say I am sitting on that spot and create a way point while sitting there. Now when going back time and time again is it going to be right on the area where I sank fishing structure? or can it still have 6-12 error? please answer this for me.

Don Collins

[LocDown]

When you get close use your si and a marker buoy. Next time you turn on the ff goto your gps diagnostic screen and see how many feet you error is.

[Dieago]

It says 5FT

[LocDown]

It's within 5+6=11 x2= 22ft max circle. The rings you're talking about are casting rings. I would still use SI and marker buoys to find the object everytime.

[rnvinc]

When marking waypoints on SI...I find they are more accurate if I mark the point where the structure seems to touch the bottom...(kind of where the structure meets the shadow)...

Rickie

[RGecy]

It really helps to locate the GPS receiver as close to the transducer as possible.  It will alleviate any deviation from receiver to transducer and then navigating back to a marked point.  If you are facing a different direction from when you marked the spot, the target can be in a completely different spot than you think!

If your GPS receiver is 10' from your transducer and you hit the mark button, your waypoint is going to be 10' off in what ever direction you were travelling. So when you return, even though you marked the structure, you really marked a point 10' away from it where your head unit was at the time you passed over it.   

As for the ring, if you are navigating to it, it is the arrival alarm ring.  But like I said above, if you are coming in from a different direction you cannot expect it to be accurate.

Robert

[Dieago]

My 999 has receiver built in. I said ring but what I should have said was the way point dot on map. when navigating to dot the little boat Icon is in route moving to way point dot when are you on top of brush/way point when tip/bow part of little moving boat icon touches way point blue dot or totally on top of it? I'm thinking I will dedicate next outing to marking a way point on a standing tree and drive to it and by it and see about figuring this out. there is one place in 25ft water I sank large 6x10 brush I can see it but dang if I can find it with a jig. I love my humminbird but I think Im going to basspro and get a Garmin for the bow. I may be wrong but my way of thinking is they cut there teeth with gps and the one I used to use in my truck never let me down. at least with BP I can return it if need be plus I want to go check out a new i pilot anyway. The 999 has help me put fish in the boat the last few weeks that's a plus and LocDown I do use markers have three on the boat must have for Crappie. If I can figure out this mark and go to thing I will be one happy fisherman.

[Dieago]

Rgecy are you saying when marking a spot while traveling say west from east then every time going back you should approach it from west to east? the unit has a setting where you tell it how far transducer is from head unit from front to rear and from side to side. Thats what I was referring to as offset.

[Dieago]

It's within 5+6=11 x2= 22ft max circle. The rings you're talking about are casting rings. I would still use SI and marker buoys to find the object everytime.

I can see it time to time with 83 in 2d but cant ever seem to see it in SI matter of fact I never see much of any structure as in brush logs or timber on bottom with SI and I have been more than 20 miles all together
 I know there stuff down there has to be! I see it in 2d??

[Gimp]

Now I'm confused. You haven't seen these brush piles on SI? Or you have and moved the cursor to them, marked them, and can't get on top of them?

[rnvinc]

I can see it time to time with 83 in 2d but cant ever seem to see it in SI matter of fact I never see much of any structure as in brush logs or timber on bottom with SI and I have been more than 20 miles all together
 I know there stuff down there has to be! I see it in 2d??

What SI range are you using...?? (Maybe it's there on your SI but you're expecting the brush, stumps and other structure to show bigger...??)

I think this is at about 65' SI range...(I would suggest even going down to much less SI Range until you get a feel for picking out structure on the SI)...







Rickie

[Dieago]

Both I have found some old looks like wooden crates piled up on side scan I cant seem to get on top of and theres one where I sunk large willow tree limbs with cinder blocks that I cant find with si but marked it with gps then another I cant find with si but am now thinking I may be not seeing one of them because i put it on edge of drop off and may be approaching it from wrong direction and si is shooting over top?? but its not like in my dreams! I was dreaming of marking with gps and getting right back on top of it. And i go for miles and not really see much of anything naturally on bottom. our lake is 15ft low and there is man made brush laying allover out of water so I would also think there should be lots still under water too. I have seen a few with 200kz 2d but when drive by in si cant seam to find it?

[newkid4si]

Don

     Here is a link to a site that has helped me understand why it is not as easy to get back to that waypoint as you would think.
     
     Boats & Electronics/ GPS and Cartography/  three articles

     http://www.biggeorgiaspots.com/boats-and-electronics.html

               Mike

[rnvinc]

Do you have any screenshots we can look at...??

Rickie

[Dieago]

I can pick the brush out of your picture fine. I use it in 10-30 ft and 50-60 range as suggested on this site. I also have the si in what is it 800kz?

[Dieago]

the first one is brush I cant get on the bottom two are evact same position and im not seeing in si that i see in down 2d

[RGecy]

I wasn't aware that they had the transducer offset feature out.  Can you take a screenshot of the menu with these settings and post for us here.  If that's the case, then once you set it, it should solve the issue I was talking about.

As for not seeing the brush, that can be tough some times.  Slower boat and chart speed may help.

As for not getting on the crates you marked, I would say that's back to the gps/transducer offset issue.

I have told this story before, but this is exactly why I have the GPS right over my TD.  I do a lot of diving and search and rescue and one time we were looking for a boat that sank in about 100' of water.  Once I found it, I put a mark on the target, navigated back to it and had my buddy bring the anchor to the back of the boat by the GPS receiver.  Once I got over the waypoint I had him drop the anchor.  When we got to the bottom, the anchor had landed IN the hull of the boat!  And I have done this time after time.  We do a lot of black water diving and you have to get it right or you could swim by it and not even see your target!

My point is...get the GPS right and you should be able to mark points and find them with no problem.....as long as you have your setup right!

Robert

[Dieago]

Robert I went out and looked and couldn't find the setting so then I looked on the cheep eagle combo on the bow. it was on the console came with boat still couldn't find it  but I seen it either on these two or the 597hd or 598si I had before the 999 but I remember measuring distance with tape from unit to side and unit to rear and inputting the distance.

[Dieago]

I think Im going to go pick up new unit for bow tomorrow And if Im understanding right. have coordinates in console unit that get me close. then find the brush mark way point with the bow unit up front where me and the head unit are at at would be closer to spot on off the front inches from bow edge.

[slabbacks]

Dieage

  I do what LocDown spoke of when returning to my waypoints.  I run and watch the SI and waypoint on the map.  When I get close I zoom in all the way (map) and I make sure the mark is going to be on my right side, my Puck is back with my ducer so when I see I'm fixing to go past the waypoint (not over it) I then watch SI screen. 

  As soon as I see the brush, stump tree ect come up I toss a marker just behind the boat off the ducer.  I know now the target is to the right of the marker X feet away.  If the wind is blowing I want it to hit the marker first and blow in the direction of the structure.

  Shut down and jump on the TM and come into the wind to your marker.  By getting on and off the TM you can pick away at the structure once found on bow unit and once hooked up the wind will carry you back off it.  Move back in and do it again with out ever running over the structure and spooking fish.

[slabbacks]

In reference to your Si and seeing structure you may consider this, and someone correct me if I'm looking at this wrong.

I see your in 27 FOW shooting both L/R.  The amount of bottom you are looking at is somewhere around 13-14' to each side once you come off the shallow stuff.   You also spoke of using 800 in SI.  You may go to shooting one side in SI while in 455 just to find something that interest you.  Change over to 800 to view better detail once you move over to better check that location.  Once you gain confidence in the unit go back to left / right and a wider search screen.  Your 2 shots look clear of any major structure and I think interference in the first shot unless you have weeds that deep. 

The last shot was taken with slow boat speed vs unit screen speed, that's why you are getting those elongated lines or a blur effect.

The structure you said may have went off the ledge,  go out into the channel and run up or down it shooting that ledge.  You should pick it up where it went over at.  Here was a ledge that had trees off it...Didn't have it on one side but you can see the difference it would have made.  Wasted space to the right and would of had better detail if I would have just shot left and/or used 800.



Do you know of anyone who has a SI unit you could go out with and run behind?  You could both scan some areas and see if your unit is seeing what they are seeing.

[RGecy]

I think Im going to go pick up new unit for bow tomorrow And if Im understanding right. have coordinates in console unit that get me close. then find the brush mark way point with the bow unit up front where me and the head unit are at at would be closer to spot on off the front inches from bow edge.

Are you saying you are going to have a transducer on the bow trolling motor with the new unit?

Robert

[Dieago]

Yes sir I am and I believe I know the answer is yes. but lets say Im going along and I see brush off to the right on SI and I cursor over to it and hit go to. now lets just leave gps error out for now. my transducer is 5' from my display. Im heading toward marked spot is unit wanting to put display on top of brush or transducer? If I have this understood now Im guessing display and now Im off by error + the 5' which could be as much as 11-16' is this right?

[LocDown]

correct.

[rnvinc]

I agree with LocDown...

The waypoint on the chart is always where the satillites calculate the GPS antenna to be...(since the antenna IS the receiver)...

So positioning the boat to get the "icon on the screen" on top of the "waypoint on the screen" is going to be re-positioning the GPS antenna on top of the structure...

If your xducer is 5' away from the GPS antenna...you could actually not even see the structure on your 2d display because the structure is now under the GPS antenna ...and not under the xducer...

Rickie

[rnvinc]

BTW...can you post some SI screenshots from the unit instead of snapshots from Humviewer...??

Rickie

[LocDown]

So let's review some of the numbers from previous posts.
6ft - distance from transducer to 999 unit
5ft - gps error after it settled down.

add those 2 numbers together you will get 11ft but the circle diameter will 22ft max but the minimum distance could be 2ft.
So your brush pile could be as close as 1ft at depth under your 999 or up to 11ft away from it.

[Dieago]

BTW...can you post some SI screenshots from the unit instead of snapshots from Humviewer...??

Rickie

LOL sure will as soon as this ice and snow melts