Thread: Am I makeing the right choice?

Originally Posted by chaunc

The spot's not moving is it? And it's still in the same place on your screen. What diffrence does it make what direction you're coming from? The spot is marked. Your gps setup hasn't changed. You get on the mark, you should be on the mark.

I have been through this several times with my dad and it took sitting down and drawing a picture for him to comprehend. Let's ay you have a 18' boat, transducer on the back and GPS on the front (does not matter if you are using side imaging or bottom scan). If you come across something and your transducer picks it up, by the time you hit the mark button on your unit you are at least 18' off since your GPS is on the front of the boat. Maybe that makes a little since. This is how I have looked at it anyway. When I first got the side imaging I noticed that I was always off to one side when I marked soemthing, this was due to the location of the transducer and GPS.

Originally Posted by mbarrett

My boat can switch between 12v and 24v by a switch

I think all the new TM's are either 12v or 24v.

I always had a 12V until 3 years ago and switched to a 24v 71# but it wasn't digital and I hated that TM. It just wouldn't go slow enough. So I sold it and when I looked for a new TM had to decide which TM to buy, either 12v or 24v. Either way it would be digital and I would run 2 batteries. I choose to go back to 12v for the simple reason that if something happened to any one battery on my boat, I could still run my T/M on just one battery. I'm glad I did because 2 weeks ago, I got to the lake and my starting battery was dead. I probably left something on. Only problem with the 12v is you can only get 55lb. thrust (+/-). Just food for thought.

thanks alot for all ur alls replys

Originally Posted by callshy

I have been through this several times with my dad and it took sitting down and drawing a picture for him to comprehend. Let's ay you have a 18' boat, transducer on the back and GPS on the front (does not matter if you are using side imaging or bottom scan). If you come across something and your transducer picks it up, by the time you hit the mark button on your unit you are at least 18' off since your GPS is on the front of the boat. Maybe that makes a little since. This is how I have looked at it anyway. When I first got the side imaging I noticed that I was always off to one side when I marked soemthing, this was due to the location of the transducer and GPS.

My sonar and gps are on my bow, on the trolling motor. I dont see the same point that you do. When i mark something on my unit, it's right under me not 16 or 18 feet behind me. I wont mark something if i'm moving away from it. I'll throw a marker out and go back to it then mark it. I see where you guys are going wrong. I know how to use my gps to put me on my spots. Maybe, if you're having a tough time with your way, give mine a try. 95% spot on when i mark it from my trolling motor.

Originally Posted by chaunc

My sonar and gps are on my bow, on the trolling motor. I dont see the same point that you do. When i mark something on my unit, it's right under me not 16 or 18 feet behind me. I wont mark something if i'm moving away from it. I'll throw a marker out and go back to it then mark it. I see where you guys are going wrong. I know how to use my gps to put me on my spots. Maybe, if you're having a tough time with your way, give mine a try. 95% spot on when i mark it from my trolling motor.

If you have internal GPS and it's up by your trolling motor and you mark it, you are right. Whatever you mark should be within a foot or two either way.

Now put the head unit with internal gps on your console and have your transducer 10FT away from it and see if you find it. That's the whole point of having the GPS puck on the back of the boat as close to the transducer, so when you mark it, you are on the spot.

Originally Posted by chaunc

The spot's not moving is it? And it's still in the same place on your screen. What diffrence does it make what direction you're coming from? The spot is marked. Your gps setup hasn't changed. You get on the mark, you should be on the mark.

If your antenna is on the front of the boat, and your transducer is on the back of the boat, or vice versa, and your boat is 16' long, then you would have a hard time zeroing in on the exact spot you want.

Most GPS units tout accurate within 3 meters. That alone makes it tough at times to find "the" spot. I've owned two Lowrance I-Finders that were dead on in locating a spot.

We've all sat over a hot spot above brush before while anything outside of an 18" perimeter around the spot was non productive. But that "one little area" would get a bite every time you dropped a line down.


If you're using a trolling motor mounted transducer, and your GPS/antenna is fairly close to your TM, then that's about as good as you can get. I see no problems with the setup.
So if someone wants to have their antenna for their GPS located away from their transducer, that's their business. My antenna is mounted right above my tranducer within 2" of it.

My Lowrance unit is on the back of the boat and it is extremely accurate. I use an H2O while in front, and have a Garmin GPSMap 192c for the front that I have not installed yet.

Bottomline is, I guess it's a personal choice. By having the antenna mounted over the transducer, you can actually confirm the spot by seeing it on the graph. You cannot do this if the antenna and transducer are mounted separately.

Trolling motor transducers with GPS antenna close by are just fine. That should be close enough.

Originally Posted by mduncan62

If you have internal GPS and it's up by your trolling motor and you mark it, you are right. Whatever you mark should be within a foot or two either way.

Now put the head unit with internal gps on your console and have your transducer 10FT away from it and see if you find it. That's the whole point of having the GPS puck on the back of the boat as close to the transducer, so when you mark it, you are on the spot.

I have the puck mounted right next to the troller, about 4" from my unit. I'm having another unit mounted on my console today with a separate puck mounted on the rail. I'll keep what you guys taught me in mind so i hopefully dont get confused about finding stuff from the console. Thanks for all the info and i'm sorry for hijacking this thread.

i always fish a spot before i save the waypoint. try to make sure your marker is about center of the spot. my antenna is on top of console right in front of me. when my unit tells me i'm less than 10' away i drop marker right off my side.