Using a Booby Nymph fly pattern I have successfully fished a two fly rig when hunting for the correct feeding level of rainbow trout in the column of water. I tie a Booby to the end of the leader on a floating line. It hovers subsurface.
BOOBY NYMPHS Hook size 10 - $US each
I then tie a length of line on to the bend of the booby fly’s hook. At the end of this leader I will fish an epoxy buzzer nymph, a Gold Ribbed Hares Ear GRHE nymph or Pheasant Tail nymph. They will sink. If I do not get success I will experiment by changing the length of the leader to search a different height in the water for feeding Rainbow or Brown trout. This method is referred to as 'top-down' nymphing.
The Washing-line technique uses a Booby nymph at the tippet of a long leader. A team of small midge pupae, epoxy buzzers, Pheasant Tails or Gold Ribbed Hares Ear nymphs are fished on droppers off the main line. They are cast on either a sinking or floating line depending on what depth the trout are feeding. The buoyant boobie keeps the leader floating horizontally under the water with the droppers dangling enticingly under it, just like washing hanging on the line. If you vary the length of the dropper you are able to fish at different levels in the water. It takes a bit of skill to be able to cast this rig. It takes practice but is worth it once you get the knack.
Gregor Fulton wrote: I use Boobies in the early and late season, when the rainbows are lying deep. I use a fast sinking line and about 6' of FC tippet. I cast as far as I can, which is a long way as fast sinking lines are heavy, dense and have a slim profile. I let the line sink to the bottom then retrieve it in jerks. As the Booby accelerates it is pulled down, then the pause allows it to rise again. In this way I cover all the levels from the bottom to about 6' above it, where in cold conditions the fish will be lying. Often the takes are as the Booby rises through the water column during the pause. I have found this method very effective. I have also used it to very good effect fishing for land-locked salmon (huchen huchen) in still waters in Hokkaido, Japan, which always lie deep, and you only see them at the end of the battle when they surface. A great fly!