Furuno: Auto or Manual?

[Gimme5]

You guys set your sounder to auto or manual range? Why? Most "experts" seem to recommend manual to get the best performance but they don't explain why. Thanks.

[Fed]

I use full auto because I don't want to have to interpret or adjust.

It will follow the bottom & change depths on the fly.
It will adjust the gain to always give a nice 'clean' picture.
I believe the sounders software is better at interpreting the raw data that I am.
I like the pictures of the little fish.

I see fish, weed, sand/mud and a deeper rock bottom by simply turning it on.

[scottar]

In terms of "range", as you get into deeper water the set will select a larger "window" (for lack of a better description) so you can get all of the picture from the surface to the bottom displayed. Your picture is made of pixels (dots) - there is a certain number of these vertically on the screen. Lets say for example we are in 100 metres of water and we have a screen with 100 vertical pixels (you have a lot more than this but it keeps the math simple) set on a 100 metre range. If the bottom changes depth by one metre, a change of only one dot will occur in the picture. If you had a range of 50 metres selected and had "shifted" it to see the bottom in 100 metres, the visual change would be two dots - and the bottom would only have to change half a metre for a visual change on the display. This extra information displayed encompasses all echo returns so you get extra visual information about everything The further you reduce the range manually and use your shift, the more information you are seeing - essentially the same as a zoom.


The other reason manual ranging has been utilised is to stop sounders "hunting" for depth when they invariably lose signal due to rough water or a poor installation/location for the transducer. A sounders programming basically tells it that if it can't find the bottom, the water must be deeper - they essentially will stop looking in the shallower depths and you will end up with 100's of metres of range displayed on the screen and no depth readout. If you have locked the sounder into a certain range, as soon as the signal returns, the image returns and everyone is happy again.

[Gimme5]

Thanks Scottar. I appreciate the benefits of range shifting and zooming for deeper water, but I fail to understand compelling reasons for setting manual rather than auto if I'm just wanting to view the entire range scale especially if I rarely encounter loss of signal. In event that I do lose signal, wouldn't the unit just keep "hunting" for depth until signal returns again which I assume would be the case whether you're on auto or manual?

[scottar]

If you are happy enough to view full screen then the advantages are minimal. As for getting the signal back after loss - some sets are better than others and over the years there have been some that never seemed to recover (boat could literally be stationary and the sounder would still be away with the tweeties). Locking them into manual fixed the problem. Most sounders in recent years have pretty good auto functions for Joe Average to do a bit of fishing. Some users though are looking for such minor changes that by using auto functions these changes can be either lost or falsely displayed due to the sounder "shifting the goal posts" so to speak - not so much with range but certainly auto filtering, auto gain and the like. IMO most of the articles written by the "experts" are aimed more so at the user wanting to wring every last little bit of info out of their sounder picture - if you don't need to drive it that level then auto is probably going to be good enough.

[stue2]

Manual for lots of reasons.
It is easier to learn to read your sounder if the range is set at say 10m.
The pic will be consistent if you are looking at the bottom 10m
Much easier to figue out what is what in my opinion