Greenfield River Anchor - The Tri-Fluke design of the River Anchor allows the flukes to penetrate the river bottom in soft and moderate conditions, or to engage rocks and structure in rivers and current. The River Anchor is a great all purpose anchor for lighter craft, or a great second anchor. Larger models are preferred choice for pontoon boats and other difficult to hold boats. Allows the flukes to penetrate the river bottom in soft and moderate conditionsThe River Anchor is a great all purpose anchor for lighter craft.