In need of some control on the water? The Sportsman Series PowerKnob makes turning and maneuvering in tight spots easier for boaters. Its precision-milled bearing surfaces and polymer body won't slip from your fingertips when you're rounding a close corner. The PowerKnob can be mounted to any wheel quickly with a simple clamp-on design, or if it's a solid-rimmed wheel, just use the provided tools to install with a stainless-steel bolt. Prices start at $44.95.