Why doesn't the water go down?

[rog]

Why doesn\'t the water go down?

I was sitting in my boat and looking at the frozen sea last Friday (well a thin layer anyway!). It started me thinking about the seawater in my engine and that perhaps it would be better drained down a little, a least away from the expensive bits like the heat exchanger for instance.

So what I wanna know is why doesn't the seawater just drain out of the engine cooling system when the boat's not being used? Presumably the water pump stops the flow on one side but is there anything else or is it just the possible vacuum holding it all in?

Can I open the fresh water filter to let it out down to sea level and will it fill back again without problem as soon as the water pump turns?

Is it necessary or worthwhile

Mince pie for the best anwswer

 

[adarcy]

Re: Why doesn\'t the water go down?

Hi rog

I am claiming the mince pie!

If you don't have an impeller ie shaftdrive then it's the vacuum formed which keep the water in (refer to syphons)
Yes to letting the water out and yes to it priming itself.

Is it necessary? Not in the south I'd have thought and it's pretty rare for seawater to freeze even in the north. Out of the water it is much more likely to freeze without the metal conduction to the great coolsink (opposite to heatsink). So out of the water, drain as much as possible, in the water don't bother.

Anthony

 

[iangrant]

Re: Why doesn\'t the water go down?

Just run the engine for a couple of seconds while you turn off the seacock.

 

[paulineb]

Don\'t know, but neither did my first husband

.. and he deserves to be in prison

Pxx

 

[ChrisP]

Re: Why doesn\'t the water go down?

Better still close the seacock and disconnect the intake pipe. Put the end of the pipe into a bucket of premixed anti-freeze and then run the engine until the anti-freeze comes out of the exhaust.
Most raw water pumps are the Jabsco impeller type which won't allow the water to back feed as the inlet ond outlet ports are never open to the same impeller section at the same time.

 

[ChrisP]

Re: Don\'t know, but neither did my first husband

Or a mental hospital!!!!!!!!!