e31,
This weight is commonly referred to as a "kettle" or a "sentinel," for the obvious metaphorical reasons.
The weight certainly can keep the pull on the
shackle of your
anchor more parallel with the seabed, and therefore reduce the need for scope.
Connecting the sentinel where the chain
shackles to the
rode is one way to go. Those using all-rope
rodes achieve the same effect by snapping the sentinel around the
anchor rode and running it halfway down on its own retrieval
line.
Note: This is a dynamic set-up: wind & current against chain and the weight and the placement of the sentinel. When the wind and/or current increases, the force on the
anchor rode increases, and the sentinel may lift off the bottom (if it is not already suspended off the bottom). The stronger the force, the more defeated the sentinel becomes and the "straighter" the entire
anchor rode becomes. Swinging radius should always be calculated as if the sentinel did not exist.
I''m sure others will be eager to add to my crude remarks. And I''m sure a little poking around the archived articles (behind "features" tab @ top of page) will yield some at-length discussion on the topic.