I went back down to the "Carp Puddle", this afternoon, to play around with my version of the "D" rig. I fished it helicopter style, but tied using 12 lbs mono and incorporating a Gardner "Rigga" hook. All I need to say, at this point, is that it was an outrageous success. I couldn't keep two rods in the water, so ended up using just one, yet still getting bites ridiculously soon after placing the rig using eight sections of the Nash "Bushwhacker" baiting pole.
It was a superb learning experience, from my perspective, as I've never used this set-up previously. I did lose a fish to a hook pull (barbless rules?) but also had a number of "occurrences" which I dismissed as liners before discovering that the "D" had actually twisted on the hook shank. This has to be a positive about using this type of venue for understanding rig mechanics? With such a high density of stock, action is almost guaranteed, so lessons can be learnt very quickly. All I can say about this particular venue is "that if you can't catch Carp here, seriously think about golf as a hobby"
Two more "doubles" for the tally but, the real lesson away from rig mechanics came in the form of getting self-take shots in a very tight swim. Plus there's always a bonus "out take" when using the intervalometer - enjoy.