This is a great way to better use the storage available in kayak hatches. It is especially good in Cobra's due to their large 10" center hatches but it will work with any easily accessible hatch.
You need some form of rope and clips. My favorite rope for this is Paracord and I prefer plastic clips like those found on a Sampo stringer. What you do is use the scupper hole posts as ends of a clothesline and completely loop the rope around them forming a single unit. Make sure that you include the clips before tying the two ends together.
Once its completed you can attach many of your accessories. Its great for your drift sock, anchor wheel, lure boxes, mesh bags, dry bags, storage boxesm etc. I keep a lot of items handy with this system and since they're on a pulley they're always accessible.