Several types are used, all normally connected directly to the inlet skin fitting.
They enable the water to be turned off when the boat is left and for maintenance purposes.
The most common are:
1. Gate valves, which have a sliding plate to open or close the flow passage through the valve. They are inclined to stiffen unless used frequently.
2. Ball valves, which use a ball shape with a hole through it. When turned to line the hole up with the inlet and outlet passages, water passes through. The handle is simply turned through 90° and it is easy to see whether the valve is open or closed: if the handle is in line with the pipe, the valve is open.
3. Cone valves are similar in principle to ball valves except that the sealing element is a cone with a hole through it. When the cone is turned through 90° it opens a passageway through the valve.
