Reel & Line-Rollcast-Jump rollcast-Spey-cast-Double Spey-Single Spey-Snakeroll

D-LOOPS.

This has become a common name for the back cast of all the Spey and roll casts. It is this anchored loop of line that is formed behind the rod that gives the weight of the fly line or energy to load the rod on the forward delivery. Depending on how efficient this is depends on a couple of factors: -
The first being that the D-loop is formed 180-degrees inline with the target and the other is that there is very little fly line in contact with the surface of the water, just the leader and a couple of feet of fly line and that there is no slack in the loop.
Always glance to the side when forming the D-loop.