Here again is a scenario that some may say should not be classified as fly fishing, ok at what point do you draw the line.
Is there a need to make life difficult for your self with a fly rod. ? well thats what you more or less do with any aspect of fly fishing, when a dead drift worm correctly fished is very likely more deadly that any other method that l know. Very few trout would refuse that one. But that also takes a certain amount of skill.
Deep water fishing is a relative skill, no doubt of that one, that fact that you are using a addition of weight either as added to the fly or other is irrelevant in my book. By what comparison do you then make between that and using a high speed fast sinking line or in a extream case a lead core full fly line. Bottom line is that you are using a means to get the fly to the fish.
If it is your choice not to do that for some reason, in that you have some other ways of thought ok, that is your option to do so.
I can only speak from a vast experience of fishing deep water techniques that is does take a bunch of practice to perfect it. It will allow for you to catch fish that otherwise by a fly rod means you would not.
Many of the rivers we fished in EU are fast deep water systems, a 5wt set up is not going to work for you there.
I of course do not have the space here to write full articel of how l would go about it but to summarise on it, as follows.
I will use these techniques for both deep pocket water situations, and when for the relative short distance that l have, l need to get the fly or flies down fast. A typical scenario would be the deep water downstream of a drop off from a weir or rock ledge, or a deep section of water found below some structure, and so on. ( WADE FISHING)
I do not use a strike indicator for this style of fishing. Out of choice l will use a intermediate line, not that the line is being used in the water, l use it because it will hang far better than a dry line and is less subject to being moved by wind.
I will use a rod from 10 to 11ft which enables me to control both my drift of the flies and also provides for a relative distance from the rod tip to the water surface. I will have something like 2 to 3 ft of the leader above the water to the fly line. I will look for the take of the fish by watching that leader or fly line
I will make up my leader configuration from straight mono, or FC, normally around 4x for trout. Do not use a tapered leader as the thicker section sinks to slow, length determined by water depth and speed, and the range that l am fishing.
The technique known as high stick works well if you are fishing close in and with a short tract of the flies, But when acomplished you can fish this way at a distance considerably further than a rod length, you may have to in some cases as you will not be able to wade due to deep water.
I do not use the addition of the weight at the end of the set up, l used to do that but not any more. If it is a one fly regulation l will tie a short section of mono to act as a stop knot above the fly on the tail. You do that simply by taking a 4 ins section of mono and use the surgeons knot to fix it, cut off the tags, leaving the knot of course.
I prefer to have the weight with the fly or shot pinched on above the dropper knot. First it cannot slip down and the tail fly will fish in line with the dropper fly. There are some circumstances that l will add further shot way above the dropper fly if l am using 2 flies, or 3.
That lesson l learned many years ago when l match fished UK style, with the float. It has to be a balanced rig to work right, or you will not see the take of the fish. If there is too much slack line between the fly and the line you can see above the surface, or you do not allow the flies to track at the correct speed, which should be the same as the current. That is a requirment of watching both the water sped and how you control the fly rod, so as you do not inhibit that, by holding back or allowing to much slack line to build up below the surface.
I would choose to use a line wt of min 6, more like 7, l am not after a surface presentation deal here.
There is one other tip l might give you here. I also cut off about 4ft from the front taper of the fly line, no need for the reduced taper, that gives me also more weight at the termination of the fly line for the hang effect that l am looking for, it is also a method l use for deep water nymph fishing when using boat drift techniques with heavy rigs.
And right now on the White river we have plenty of deep water !!
These methods have enabled me to catch some great trophy fish of many species in past years, whic l doubt l would have done by other methods with the use of a fly rod .