A tension foundation is provided for holding a buoyant object in flowing water via a tether. The tension foundation may include a spine component, rotation members rotatable about the spine component, slats, and additional features. The rotation members can include multiple types with distinct dimension ratios, which may be arranged in an alternating pattern. During operation, the tension foundation advantageously provides increased contacting edges to grip an uneven surface, such as a rocky lakebed or river bottom.