i have a lowrance flasher on my console that I have trouble reading it to its full useage?  can you tell me the advantages of using a flasher and any extra info on understanding how to read and understand the grayline, fish symbol and surface symbol?  if your running the boat at high speeds how are you able to put all this to work for you ?  thanks    

I definately use my soanr when running high speeds.  I only pay attention to the depth at that speed, but that is pretty important to watch.  If I am scouting an area at slow speed I will watch for bait fish, target fish, structure and bottom density.  In a nutshell, thin gray line indicates softer bottoms and wide grayline indicates hard bottom.  You should read your manual.  It is probably your best source for info for your setup.  If you don't have one you can download one from Lowrance.com.  Look under utilities on the right side of the page.

I know those Lindner boys swear by a flasher. Al uses his quite a bit on Angling Edge. I don't know the first thing about them.  

It almost sounds to me that you are refferring to two different pieces of equipment in your post. A flasher has no grayline. It only has a led that spins in a fast circle and lights at different points to indicate depth and other features.

Reading a flasher is a very different from reading a graph with a LCD screen that shows a "picture". You can use a flasher to tell bottom composistion, baitfish, stumps, treetops and fish, but for the newer generation that grew up with a LCD screen it is more difficult. The little subtle flashes all mean something on a flasher, but to the untrained eye they are just that, flashes. (Mine included) Some old school fisherman swear that they can tell the difference between wallye and bass with a flasher. The plus to a flasher is that there is little to no delay in the reading that you see. With graphs, even the newer ones there is a small delay due to processing time as to what you see. No where near what it used to be, but still there a little.

As far as using a graph, at higher speeds you are not going to get all the information you are looking for. You will mainly get the the depth reading and other large events that change under the water. (River channel lip to channel bottom, large thick weed beds) There is just too much changing for the unit to process that information while on top pad. Now if you slow down to a steady speed less than 15 MPH or so you will start to see more things happening on the screen. If you slow down to a trolling speed or even down to idle, you will see everything that you are asking about.

As far as fish symbols, are you reffereing to symbols or arches? I do not use the Fish ID feature for the simple fact that it wil pick up junk and call it a fish. (Tree limbs, bubbles, and schools of bait fish.) I want to be able to tell the difference between a small school of bait fish and an actual fish. Learn to read and see the arches instead of relying on the fish id feature. It will open the door to a whole different aspect of reading the graph. You also can not see the thermocline with the Fish ID turned on. Another key thing that I like to see when fishing in the summer time. As far as arches go, they will look different depending on the fishes location in relation to the sonar beam, and the direction and speeds that the boat and fish are traveling. They may look similar to either of these: \ / /\ __ . (Understand that the keyboard was not designed to make fish arches, but that will give you an idea.) The two half arches show the fish in the outer cone and off to the sides. (Since it is a circle, the sides can be front, back, left, or right.) The true arch is a fish that has moved from one side of the cone through the center and back out the other side of the cone. The flat line is where a fish is in the cone, and is either not moving or the boat is not moving fast enough to make the arch symbol appear. It will remain a flat line as long as the fish is within the cone also.

By "surface symbol" are you referring to the noise/clutter that is seen at the top of the screen? If so, then that will vary from lake to lake. It is a reading of different things. It may be an alge bloom, plankton, or it could be mud that is present in the water from run off or eroision from boat activity. In the clear lakes that I fish, most do not have a lot of surface clutter, but when ever I go out of the mountains into the lowlands I see it. It is normally worse in the summer as there are more alge and plankton near the surface than when the water temps are cooler. You want to see some clutter. If you block it all out, it will take aawy from part of the effectivness of the unit. Same said for too much clutter also. If you use the sensitivty setting in manual mode, by using the surface noise reject at different levels, you can use the surface clutter to help set the level of sensitivty to see some things that are over looked when the sensitivity is in automatic mode. Set the surface noise reject to say medium if the water really has a alot plankton or alge present, then start turning the sensitivity up untill you start to see a second "false" bottom. You do not want too much of a second bottom, just enough that you can barely see it on the graph. You will know it when you see it. It is a real P.I.T.A. if you are on a lake that has constant depth changes though.

What x-trued said about grayline is dead on. There will be different shades depending on the bottom composistion. Reason being is that the softer the bottom the more of the sonar is absorbed by the bottom and not returned to the transducer. Resulting in a thinner, lighter grayline. (Vice versa with a wider dark grayline) Sometimes you will have a very thin light colored grayline with an immediate darker thin gray line underneath it. (The devil is in the details here) This could represent a rock bottom that has been silted over through the years in an aging reservoir. This could play out to be a prime area for fish that like to spawn out deeper. A thick light colored grayline also has another meaning as well. It can mean submerged vegitation. If you look at the shore and see that it looks like it should be fairly hard but the graph is showing a questionable bottom, then throw something that will get down to that depth and see what is down there. (What is stuck to the sinker on a c-rig or to the trebels on a crankbait) In late spring and early summer, the weeds are not that tall as of yet, so they can look like a soft bottom, and be hiding some very nice fish. As summer progresses you can see the weeds on the graph alot easier as they will be much higher from the bottom.

These are some of the things I use my graph for. I am sure other people have other things that they use theirs for as well. Time on the water will be your best teacher. If you have the manual by all means read it, then re-read it, and keep it with you on the boat while fishing. It will be your best source of information when you are on the water and can't ask anyone a question that you are not familiar with.

Edited for stupidity. Got my grayline colors bass-ackwards. Too late to be typing technical stuff that requires any train of thought.