Being able to convert your engines raw-water intake into an emergency bilge pump is an important safety feature. A discussion on the subject that appeared in SAIL (March 2009) suggested closing the raw-water seacock first, disconnecting the intake hose from the seacock, and attaching an extension hose long enough to reach the bilge. This may work, but in my experience, when it is time to pull a hose off a double-clamped seacock, or any fitting for that matter, the quickest way to get the hose free usually is to cut it.
Thats why Ive installed a permanent T fitting, with a male fitting and a valve, in my boats raw-water intake line between the seacock and the raw-water strainer. Any time I need to use my engine as a bilge pump, all I have to do is to quickly close the seacock and open the ball valve. I can use this hose for any number of thingspumping the bilge, giving the engine a freshwater flush, anti-freeze winterization, and so forth. And I can make the change while the engine is running. This is much easier than trying to pull a double-clamped hose off a seacock. Very often the result will be a damaged hose and/or seacock fitting.