To prevent fuel loss from the tank if the fuel feed pipe fails, a fuel cock or valve
must be fitted in the fuel feed pipe, as near as possible to the tank. The fuel
cock or valve must be readily accessible, so that it's easy to reach and operate
as soon as it's needed. As it could be a crew member or even a fire-fighter who
is trying to shut down the fuel supply, its position must be clearly marked.
It's also a good idea to have some way of operating this valve or cock from outside
your boat's engine compartment.

Alternative ways to meet this requirement include:

• making sure all fuel pipes, including those on the engine, are above the top
  of the tank, so that all fuel in the pipe can drain back to that tank in the
  event that the pipe is damaged
• fitting an anti-syphon valve on the tank
• fitting a manual shut-off valve in the fuel feed line at a point where the line
  is self-draining to the tank
• fitting a solenoid valve (with an emergency manual over-ride) at the tank
  which is only open when the engine is being started or running.

In the event of a fire in the petrol-engine space it's vital that the fuel cock or
valve can be easily accessed, so that the fuel supply can be cut off immediately.
In all gravity-fed petrol engine installations where the steering position is away
from the fuel tank this means a second fuel cock, or other means of operating
the main cock or valve must be fitted close to the helm. [2.17]