I doubt if any of you can help me but I thought I’d give it a shot.
My fish finder is reading the depth at only about 1/2 what it really is.I have the transducer velcroed to a strap wrapped around a pontoon.
Any ideas…I’ve emailed the company basically asking if the velcro mount could be the problem but no response so far.
I might suggest,
IT’S BROKE!
Possible…it is new…
Here is what I would do first. The graph will read water depth and bottom depth so I would make sure that the AO (bottom depth) feature is set correctly. The two different types of depth readings should be covered in the manual. I suppose you could always go back to the default settings. Secondly I would make sure the transducer is connected, mounted, and positioned correctly to scan and read correctly (also in the manual). Then if all that failed, I would contact the company. Good luck, Phil.
Robert…yes, one day I spent with the thing set on reading only the bottom 10’ and paniced…figured that out…then went out and found depths to 26’…but lastly am only getting readings to 13’ occasionally…went to defaults…and of course the manual isn’t in to pontoon mounts unless it is a side mount…at this point I’m thinking it’s a mounting problem???
I know there are some folks here that bought this model when I did and thought maybe they knew some thing…
Ducksterman,
A temporary easy solution is ,since it shows only half the actual depth, simply multiply the screen reading by two. For example, if the screen reads 8, multiply that by 2 and arrive at an actual depth of 16 feet. For ease of calculation, you can print up a “pony” with the answers. 
:lol:
Mark
Marco, I knew I can always count on you…but that is really complicated :shock:
Ducksterman,
The Depth Finder I used to have had a internal bow mounted transducer and it worked fine.
My Console mounted Graph had a external stern mounted transducer and that was required.
I called it Fish TV and I was fascinated by the fact it was a Video screen and I could even watch it at night.
Didn’t get much fishing done but it was interesting!
Is there a Hot Line you can call about your Bottom Line Unit?
Maybe the company that built your pontoon boat would have some ideas!
Marco’s Idea! OH MAN! :?
Doug
Another problem might be if you are using a trolling motor or mounted the transducer too close to something that might cause interference. Just another thing I thought of that could cause problems. 
I started with the BLF 1101 a few weeks ago. I had issues with it also, so I returned it. If you still have that option, exchange it for a Humminbird 500 series or Matrix 12 or a Eagle Cuda, Fisheasy, or SeaFinder. The performance is like night and day when compared to the BLF’s. I don’t know what you paid for it, but the Cudas, and Fisheasy’s are a real good buy - get a dual sonar model, designated with “DS”.
I use a strap that is made specifically to hold these fish finders in place on an inflatable tube. Its made by Scotty. I got it at Cabelas in Dundee Michigan; however, their website does not show it. Here is info from Scotty’s own website:
http://www.scotty.com/marine/products/p … inder.html
For more info on Pontoons, Float Tubing, and Fish Finders…check out the forums at
http://www.bigfishtackle.com/forum/Floa … T_P184642/ go near the bottom for a listing of prior
sonar threads - you might find more answers there on these items.
Duck-- Here’s what I would do: first call 800-633-1468. That’s the Humminbird customer service line. Do this when you’ve got time because they can be busy. Humminbird bought Bottomline two-plus years ago, so they are the folks you want to talk to. Also realize that this brand is an orphan; only the Fishin’ Buddy depthfinders still exist, and I think those are now Humminbirds.
You still should be able to get service from the company, but…parts may be a different story.
I know very little about depthfinders as far as making them sit up and do tricks. If you’ve done the re-set of defaults and played through the manual, then you’ve done what I would suggest from the software side.
What I would check from the hardware side is interference (as suggested earlier) from trolling motor wiring, transducer location, the battery and connections and the transducer itself.
Since you’re running this off a 'toon, you probably aren’t using a trolling motor, so interference isn’t an issue. I would re-check the battery and connections to make sure the power supply is what is needed and that you have a good flow of juice with no corrosion or anything that might limit the flow of electricity.
As for the transducer…if it is fully in the water and not mounted above it (gotta point that out) on the curve of the pontoon, then location is probably fine as long as there isn’t anything that might float under the transducer like a strap or flap or whatever (going from my own experience here). As you’re probably aware, transducers don’t shoot through air very well, and they don’t shoot through things containing air (such as wood or foam).
The last thing I would check is the transducer itself. Sometimes there is a buildup of crud on a transducer and a light sanding of the face will get rid of the problem. It could be that your transducer has a build-up of finish or coating or crud of some kind. I would first check with the above folks at Humminbird to make sure that doesn’t invalidate your warranty.
If you’re given the option, I’d trade for a Humminbird unit in a minute. Bottomline had a lot of problems in the later years of production, and the new 'birds don’t. I’ve got two on my boats and like them. Even the low-end Humminbirds are good units.
Hope this helps.
Keith