How much pressure will a scupper intake produce?

a scupper or scoop intake will produce how much pressure in a 3/4 line? enough to fill a sac or a cuople of sacs?

Depends on the boat speed.

My boat came with two that fed the rear tanks through aerator pumps. With the pumps off it takes about 10 minutes to fill the tanks at 23-25mph, these tanks are only only about 150lbs each. Everything else being equal it would take 30 minutes to fill a 500lb sac.

It also depends on the location. If mine were farther back they would probably fill faster, they are at the front of the motor next to the transmission.

It also is very dependent on the "head", how high the water needs to be lifted above the surface.

Got a 1 1/2" scoop on my system. 1" ID lines. Aerator pump system. It's enough pressure to fill a sac or two, but I would take some time.

I've never filled them without using the pumps. But, we were out on a quick skate session one evening and I had the ball valves closed off at the intake, right by the scoop. I didn't realize it, but the rear line valve was left open about 3 degrees. We were out for a 2 hrs tops, but I had about 500 lbs in the sac when we got back to the house.

There is a significant amount of pressure. Just not sure I would want to wait for it to fill the sacs. Gas $$.

you'd pry have better luck with unrestricted lines: no pumps.

edit: i agree with Mikeski, closer to transom would have more pressure.

(Message edited by denverd1 on January 10, 2009)

Here's a system I helped a friend build which worked well and very quick to fill.

http://www.wakeworld.com/MB/Discus/messages/65921/199086.html?1105114843

Very cool. I am thinking a 3/4" scupper for fill and an aerator for drain for a large sac. Would have to use a sprinkler valve and solenoid for the main line so you would not pop the sac. You could drain through same line if you wanted

Very cool. I am thinking a 3/4" scupper for fill and an aerator for drain for a large sac. Would have to use a sprinkler valve and solenoid for the main line so you would not pop the sac. You could drain through same line if you wanted

Jim,
What size is your intake?

I am not sure, it was a friend of mine in AZ while I was working on a project there. Maybe Alan will see this and chime in. I think it was all 3/4" pipe fittings so the hoses are 1" I.D. We chased the threads on the scupper with a pipe die to get the taper to fit the pipe threads of the ball valve shown in the picture. The scupper is straight threads and seemed to be the same pitch as NPT.

I filled 1500 pounds in 2 mins with my 2x 1&1/4" scoop based system, then blew the lids off both tanks. Trust me, you can produce plenty of pressure and flow with this type of system.

http://www.the2001.com/index.php?name=PNphpBB2&file=viewtopic&t=861

Ours is about the same, only one pipe (1 1/4" I think), one valve and one 250 litre bow tank to fill though, 3 or 4 minutes at fast idle and she's full. I'm sure it would make a lot of pressure going faster but the pipe doesn't reach the water once we're on plane as it is plumbed out of the transom with a 90 degree elbow and not under the hull. I'd like to redesign it at some stage but it's Summer and pulling up the whole floor and dash doesn't appeal to me right at the moment.

Darren's set up is a pretty slick piece of plumbing, certainly fills fast.

(Message edited by jtnz on January 11, 2009)

hey darren, i was hoping you would show up...