Intake strainer and water pressure coming in.

I was going to take the plunge this weekend and drill a hole to install an intake strainer for the ballast system. I was of course going to put a ball valve first to beable to shut off the intake if needed. I was wondering if anyone has had any problems with amount of pressure coming in. I got a 600psi ball valve. Also I was thinking of using pvc. Is the joints going to be strong enough?

mph PSI
10 1.4
20 5.8
30 13.0
40 23.2
50 36.2
60 52.2

I think these numbers are right. Anyway, 600 psi will more than cover it!!!

Ops...

Should have said use bronze valve with bronze intake. You should have strong fiitings on your hull incase you have to shut it to prevent a flood.

Once you're past the first valve go ahead and use PVC valves

I ran 1" PVC up under the gunnel to the back tanks and sacks and the pressure has blown a couple joints when driving over 30 mph. Granted i am no plummer and probably used the wrong glue or something. Now i just only open the valve about 3/4 when traveling over 30mph. The flex lines up to the valve I used 10 feet of 1.5 " spa hose and that has held up fine for 300 plus hours.
The first ball valve is mounted directly to the intake strainer, and i close it before i pull the boat out so the pump will hold the prime. I dont like the PVC valves because they take a lot of leverage to turn.

Well the hole is drilled. And I am ready to start plumbing. I am thinking I am going to use metal pipe up to the pump then flexible radiator hose from there. Anybody else have a better idea. The spa hose if a good idea Troy I am going to check that out.

Will a intake strainer creat enough pressure and flow to sill sacks without the need for a pump then? I realise that I would need to drive along at 20-30 to fill them but it would be easier than messing around with a pump.

I don't know Jay, I will am going to hit the water this week with my new install. I will try to get a feel for how much pressure there is. I don't think there would be enough. You would have to get a ball valve to shut when you get the water in. I don't know if there would be enough pressure to open a check valve. If you going to go thru the work of putting in a strainer, throw in a pump too.

With a scooper-type thru-hull fitting, the water pressure will fill the sacks without a pump. I have the hippo system with the electronic solenoid valves and the water pressure will force past the valves at speeds above 25-30 and slowly fill the sacks without the pump on. If you use the scooper intake, you definately want a valve at the hull.

My scupper intake strainer fills at speed as fast as with the pump on.

Where do you get the scupper intake from?

Craig - marinehardware.com has the best selection i've seen.

James - interesting numbers, much higher than i would've expected. are those empirical or theoretic pressures?

That's static pressure (I hope...lol).

Obviously, the scoop wouldn't be as bad as a static tube. The only point I was trying to make was that 600 psi plumbing should be fine unless you are running a boat like this.

http://news.bbc.co.uk/1/hi/uk/1568630.stm

reference for non-engineering people
http://www.howstuffworks.com/question597.htm

The following site has similar numbers (mine were based on metric water...lol)
http://www.tflx.com/pdf/marspd~1.pdf

Oh right, the question you asked.... theoretical!

Well I was going to tee into the raw water intake to run to a pump to fill my fat seat and fat sac but I might just fit a scoop intake and give that a try as its a 5 min run at 25-30 mph to our ski zone anyway so that should force enough water in with out the need for a pump and then it will drain nice and easy when on the trailer.