what size chains for a trotline?

Hi Everyone! Does anyone have any tips on what size, weight, and length the chains should be on a trotline? I'm wondering if a tight trotline sends vibrations down it as the baits go across the "roller" (I don't have a roller, I use a 1-1/4" PVC "U" fork) and scares the crabs causing them to drop off.

I typically run a 500' trotline. Each end is set up with a cinderblock for an anchor, 25' of 1/4" poly rope to a float, 25' of poly rope from the float to my chains, 500" of trotline (it's that locktite stuff, I think it's 5/32" dacron, or something like that, it's not the three strand twisted sisal type), and then an identical system at the other end. The chains that I use are 3/8", 24" long, and weighs around 1.5 pounds at each end. The anchor/chain combination is enough to create a pretty tightly tensioned trotline, ie, when I run the line, it does not droop, or have any slack in it as I work my way down the line. I use a 1-1/4" PVC type "U" fork only about 1" out of the water, that is, the trotline barely comes out of the water as I run it. The trotline is tight enough that as the baits go across the pipe there is a little "thump" on the line.

Yesterday when I was crabbing in the Baltimore Harbor, I noticed that a guy doing relatively well crabbing a trotline had very slack tension in his trotline. His "U" fork was 6" above the water and the trotline was very slack as it drooped down from the "U" fork and back to the water. My guess is that to get that slack of a trotline, he couldn't have had much more that a 24" dogchain sized chain at each end. We were crabbing in Baltimore Harbor where there is not a significant current (as opposed to the upper Patuxent river, where I used to crab were there was an incredibly swift current where you really needed some significant weight to anchor everything).

So my question is, what size chains and weights are successful trotliners using? What type of tension is desireable on a trotline?

Thanks,

Sidestepper
Severn, MD