Re: What size,type and length anchor rope ?
Is this simply for fishing?
The rule of thumb is to let out 10 times the depth of the water, although most usually only let out 6 to 7 times the depth of water. This is where a fishfinder comes in handy. If I am anchoring overnight, I let out 10 times the depth of water, along with a secondary, although in the tin can that you describe, Ill assume you are simply spot fishing. The type of anchor is also important, depending on the bottom that you are anchoring to. (Mud, rocks, silt, etc...) Adding 6' of chain at the end of the rope, attached to the anchor, also helps keep your line more horizontal, locking you in position. The more horizontal your anchor line is, the better.
Drive into the wind, passing your intended destination by the appropriate amount, drop the anchor, then reverse until your anchor bites and the appropriate amount of line is released.