I use 2 anchors, both fluke type, 20 pounds, on 120 feet of rode (anchor rope). Each anchor is attached to 4 feet of heavy chain, then the rope. I tie off to the boat cleats on bow (when only anchoring temporarily ) or bow and stern (when anchoring to fish overnight). When deploying both anchors, I make sure to be headed into the current bow first. Using two overnight avoids tangled fishing lines due to boat spin on a single anchor. My boat is a 16 foot Glastron Sportster.
If you plan to anchor in 20' of water, let out @ 80 feet of rode to allow chain to lay on bottom, allowing anchor to get a good bite.