TF’s experts answer your angling queries
QAs you know, finding the depth of water is important if you think that is where the fish are. Coarse fishermen use a weight and float technique to find depth. Is there a way for fly fishermen to find depth? Tony Wills
STEVE CULLEN REPLIES: The method that you mention is called plumbing the depth, where coarse anglers use a weight and float so that they can get an exact idea of the depth of water at which they are fishing. But, and this is important, trout, unlike most coarse fish which feed on or near the bottom, can be found all the way throughout the water column. Finding their feeding depth is therefore far more important to us than finding out the actual depth of the water. Unless the water is very shallow forget using a similar method to coarse anglers. The weight of the fly needed to pull the floating fly down would be very dangerous to cast! But to answer your question first, how to find the depth of the water you are fishing. The most effective way is to set yourself up with a fast sinking fly-line, and I’d suggest a Di-7. It sinks at seven inches per second, so makes everything pretty straight forward – in layman’s terms it falls through the water at just over a foot every two seconds! To this fly line attach a short length of leader material, say 8lb breaking strain, and a weighted lure. Best tie it on a dry fly hook so that you don’t lose it (the hook will bend out if snagged). This is a throwaway fly, you won’t fish with it, it’s just for testing the depth. Now, simply cast the line out and start a slow roly-poly retrieve. Start with 10 seconds, cast, leave it 10 seconds, retrieve and then just repeat in 10 second increments. You’ll soon get a pretty good idea of how deep the water is as the fly will snag weed and detritus as soon as you’re near the bottom. You can use a similar technique to find feeding trout, but this method is best used very early in the season when the trout are deep or again in the middle of the summer. The rest of the time I’d prefer to use a bung. Use a full floating fly line, with a bung on the first dropper and three flies underneath. Heavyweight Buzzers would be the best bet, spaced four feet apart. This method too will give you an idea of where in the water column the trout are feeding.