Canoeing.com Definition: Mesh, nylon or polyethylene bags are easy to pack and create sufficient canoe anchors when filled with rocks. Most are 12” x 18” and made from quick drying materials. Many manufacturers also offer canoe anchors. Available in a minimum of 1.5 lbs, required weight varies with weight (of canoe, gear and paddlers), conditions and current. 3 lbs is generally sufficient.