Those are great Pete, thanks for sharing!
Here's a picture of my "catfish" derreck:

The original color (bright pink) has long ago faded due to ultraviolet light from the sun and I might have to get a can of spray paint to bring it back to being easy to spot.
In between the two uprights down on the base, I used a simple clothes hanger to bridge the gap and the fishing line attaches to a swivel in the middle of the clothes hanger. It drops straight down into the water and the weight helps keep the derreck upright.
I did experience one tip over and the light up on top was upside down, came off, and disappeared into the water. I replaced that light and used glue this time. If a large gust of wind comes along, it might tip over again.
This 1st derreck was just an experiment, later I plan on building some more based on this design, but they will be refined somewhat and hopefully I can incorporate some type of flag or light that will indicate a fish on.
Right now I'm just happy my catfish derreck didn't leak any oil. From the best I can tell, that would mean trouble, big trouble.
AMERICANS: Willing to cross a frozen river to kill you, in your sleep, on Christmas, totally not kidding, we've done it.