1870 F fish finder settings



Ok I just bought this unit this year, I have been using the Lowrance HDS units for awhile but have owned everything from Si-tex to Garmin just came back home to Furuno....
I set up the transducer the same as the P-66 that is still on the boat, just on the other side of the transom.
I fish in 500 to 3500 feet for Tuna I only really want to see the top 250 feet. I have the screen split at run speeds 25 35 kt I no longer get any bottom feed back at about 400 feet.
I cannot get the finder into manual (it says it is) I have no control over where I am looking for fish.
I am looking for some guidance on settings, I have moved things around and don't really see much effect. Im sure it is not the finder as when we are at 125 feet fishing close in I show very similar readings to the HDS unit that is next to the Furuno. still cannot get the manual to work in shallow water.

I have to say that the rotary dials in ruff water make it hard enough that fiddling with settings on the 2 hour ride is not going to happen. I just need to start out good.

Thanks for any help..

The boats moored so getting screen shots will take some time, but can do.
Desert Bear,
Welcome back. It sounds like you have a couple of issues going on, first of which is the sounders performance when you at speed. The key here is trying to get smooth water flow over the face of the transducer. This can be very difficult with a transom transducer specially at higher speeds. Unfortunately there are very few settings (sounder wise) that help in turbulent waters. Without see how your transducer is mounted my only suggestions would be to use 200Khz, manual range and a manual TX Rate of 20 when running. As far as working with the sounder menu's may I suggest grabbing a cup of coffee using it at the dock in the demo mode. This will give you an opportunity to go through menu's and settings in a calm environment. The 1870 is a great sounder and will serve you well. If you should have any additional questions please let us know.



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Yes Thanks for the reply.
It is pretty hard to find calm water for the p-66 to travel in. I think it is doing a pretty good job considering. I have a Farrell block and old transducer left from the prior owner I don't know anything about it because all the electronics were stolen before my purchase.
It was hooked to a Furuno unit but its not marked, my point is I think this would be the best result. Maybe next season.
I am headed to the coast tomorrow and will take your advise. I didn't realize that demo mode was a working tool.
I am not afraid of being a button pusher so I am sure I have something out of sorts. I may do a default rest and start from there.
I will let you know how I do.
I would really like to get this unit running tip top as I installed it just for the fish finder, with the HDS on a foggy day I am stuck with a choice of seeing where I am going (radar,GPS) or what is under me and water temp. With the new unit I should get the rest of the picture.
Ok took your advise and a copy of the INSTRUCTIONS ;) spent and hour or so with that.
The big one was turning off the bottom discrimination to get back the manual control.
Looks pretty good in the marina at 12 feet of water. The other big revelation was that the manual depth control is set to RANGES not necessarily some thing I can adjust on the fly.
I reset a couple of the ranges that I know I will use most (200 feet for tuna).
I am planning on using this weekend I will let you know how it goes.

Desert Bear,
Glad you took the time to work with the 1870 at the dock, you will find it was time well spent. Let us know if you have any additional questions after your next outing.