The Silt rig is basically a Helicopter rig in it’s make up, the only difference being that the rubber bead is slid up the anti-tangle tubing or lead-core to the depth of the silt that you are fishing in. In doing this the hook-link isn’t pulled into the silt burying the hook-bait.
To find out the depth of the silt you use a Marker-Float set-up with a length of white wool tied to the lead with the other end tied to the swivel which runs on the shock-leader/main-line.
The link between the Marker-Float lead and the running swivel that is on the shock-leader/main-line must still be of a suitable breaking strain material with the wool accompanying it, not instead of it.
Once set-up cast out to the silt and leave for ten minutes or so then reel in, the depth of the silt will be stained into the wool.
Considerations
The Helicopter/Silt rig does solve many problems, but not without having it’s own inherent ones.
Firstly when playing a hooked fish you do not have a direct pull on the fish, in other words the strain of the fish is being taken on the rubber bead or sleeve of the lead and the anti-tangle tubing or lead-core, not the direct tension of the main-line.
Secondly the Helicopter/Silt rig is not particularly weed friendly, as it is prone to snagging.
Once the lead is snagged the hook-link can slide up the anti-tangle tubing or lead-core making the problem worse, hence the need for a more direct pull and/or a safety-lead set-up.
Finally, for fish safety, make sure that the rubber bead, which acts as a depth stop, can slide easily along the anti-tangle tubing or lead-core.
In the event of your main-line snapping the hook-link must be able to slide up the anti-tangle tubing or lead-core pushing the rubber bead/depth stop with it as it slides off to free the fish from the lead.