Boat steering wheels and steering systems
This category holds boat steering wheels and with them hubs, adapters and spinner knobs. What has to match is the shaft taper, on leisure boats almost always the three-quarter-inch taper with a key. Rim diameter changes the effort at the wheel, not the number of turns lock to lock, which the steering ratio sets. And dish depth decides how far from the console the rim ends up.
Boat steering wheels and steering systems
This category holds boat steering wheels, that is wheels for the helm console, and with them hubs, adapters and knobs. Decorative wooden ship wheels for the wall do not belong here, because they have no tapered hub and will not go on the shaft. A wheel is chosen on four numbers, namely the hub, the diameter, the dish and the thickness of the rim. The material is usually stainless steel or polished aluminium, and the number of spokes, typically three or five, is mainly a matter of looks.
The first and only number that has to fit exactly is the shaft taper and the hub. On leisure boats practically one standard holds, namely the three-quarter-inch taper with a keyway, which in millimetres is roughly nineteen at the top and seventeen at the bottom. The wheel seats on the taper, is secured with the key and pulled up with the nut, so nothing gets drilled. If the boat has a different hub, an adapter solves that rather than grinding the shaft down.
The second number is rim diameter, and it decides the effort, not the number of turns. A bigger wheel turns more easily because it has the longer lever, only it takes room between your knees and the console. The number of turns lock to lock it does not change, though, because the steering ratio itself sets that. If the wheel you have now sits well in your hands, stay within an inch of its diameter when you replace it.
The third is dish depth, that is how far the hub sits behind the plane of the rim. A flat wheel leaves the rim at the console, a dished one pulls it closer to you, and it does so without a spacer under the hub. Thirty-five to ninety millimetres is the usual range, so the gap between the extremes is half a hand. Measure therefore not only the opening in the console but also the distance from the rim to your knees, because that is exactly where the dish takes.
The last is the spinner knob, which clamps onto the rim. With it you turn the wheel one-handed, which with cable steering helps with the effort, because there is no assistance there, and with hydraulics helps with the number of turns, of which there are more lock to lock. It fits rims of roughly sixteen to twenty-five millimetres, so measure the thickness of the rim before you order one.