12 Volt inline water pump

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Thanks Roachie much ppreciated the whale pump seems the go, ta

Beware the Whale.
I have one in my setup and they will allow flow withot power.
My outlet is above tank level, but given a fairly full tank and a steep incline it can drain (even if only partly) through the pump.
I installed a 24vAC irrigation solenoid valve (Yes, to my surprise it does work) wired into the same switch as the pump and this has solved the problem.
I have had mine for 4-5 years without trouble and as others have said, they take up little space.
Given the option I'd go for gravity.

Gordon

Whalers are self priming.

Correction: Sure-Flo pump

Odd that the link is not working. it does from my favorites but try putting the http:// in front

" target="EOF" class="lbg">www.dynaplas.com.au/

And that of course is the problem with electric pumps versus a gravity or hand pump when using precious fluids - they can be wasted.

You're dead right there. When I was setting up my set-up I quickly discovered that I need an in-line tap at the point of use as after turning the pump off syphon gravity took over withwater continuing to flow.

I've used awhale in several vehicles over the years, work well, currently have one pumping diesel from the aux tank to the main one.

Rod,

Being an old offshore racing yachtsmen, it is notable that very few boats have electric pressure pumps for water supply but use manual types.

The reasons for this I suppose are two fold in that race yachts don't carry that much water in the first place so its pretty precious stuff and hand pumped water is less wasted and of course the other is as you describe with syphoning a real threat on tipping and rocking boats.