Not at all, and I think my reputation for opposing anything that harms a fishery resource or habitat is well known. An outboard prop advances the boat by digging in the water (and any grass or bottom it contacts). But a chain has smooth, rounded links, and the chain slithers across the bottom much like a snake would. Remember, too, that when you drift with the chain you are drifting with the current, so all grass is lying in the direction of the drift. The chain simply slides over the grass. Another point: The chain is supported from the boat above, and there is very little pressure on the bottom.