Decoys and decoy string

Why do I have 8 feet of decoy string on my decoys when I hunt water that is only knee deep?

I think I will cut that down to 3 feet of string. Every time I go to pick up my dekes (that's decoys for all you non-duck hunters out there) I wind up about 15 miles of string. I think that shortening the string to 3 feet will make me happier about myself and improve my hunting skills.

I Duck hunt. Duck hunting is what I pretend to do at least actually its more like shooting and bird watching combined. I shoot and then watch the birds fly away.