After a couple test runs this weekend I think I have this setup dialed in.
Put the boat in the water on Friday for the first test and learned two things:
a) the cable clams sealing the wires would leak a very small amount of air into the chest when the pumps were pulling a vacuum. Since the pumps can only pump water the air/water ratio slowly dropped bc of this air leak. No problem, undid the cable clams and filled the void between the two parts with 4200.
b) when underway the intakes are bringing a 50/50 air/water froth. Again since the pumps can only evacuate water we began to drain the chest. When you are running there is positive pressure in the chest so the simple fix was to vent the chest. this allowed the froth to enter the chest quicker then the air could be vented off.
decided to use a check valve to vent this chest automatically, we tested the next day with a check valve installed and it worked nicely.
As discussed earlier the size of the intakes had me concerned. This could have been a problem and was in the beginning. In talking with a few people it seems as though the majority of these setups are not air tight. I believe this brings the intake size into play.
Initially before I filled the cable clams with 4200 they were sucking air. Now anyone who has installed a cable clam know how effective they are at sealing. They would barely leak a drop of water. When you put the pumps on you are dropping the pressure inside the chest and it is going to draw something from the point of least resistance. Apparently the intakes were only the path of least resistance up to a point where it would start bringing in air from the wires and water from the intake. Once I sealed them up better the path of least resistance is now the intakes only and it just pulls water in faster. So really I think the key to the hole thing is being able to pull a good vacuum inside the chest. if there was no vacuum a 2" hole can flow just shy of 1600 gph at rest. these two 1" holes are flowing over 2400 gph at rest.
Now when you are on plane running 40/50/60 mph it is the opposite. the froth is coming into the intakes as fast as it can building a strong positive pressure. The key now is to get the air out as quick as possible in order to keep the chest full of water. When running the check valve opens up and air/water come out of the attached 3/8" hose at a pretty rapid pace. I believe I am going to mount a flush fuel vent somewhere on my euro transom and plumb the check valve to it so it sprays the water overboard.
Below is a picture of the chest just sitting in the bilge. I will permanently mount the chest this weekend hopefully. I will also be replacing all the livewell hoses.
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