Raw Water Pressure Relief Dump Questions

[CRC]

I discussed this a little here on another thread but now I have two questions. I will be installing my pressure relief valve and dump tomorrow. I plan to dump out the rear starboard side next to the bilge pump dump. Is there any reason not to go through the side and above the water line? (transom is fully cored)

 

[Brownie]

Good is that you can see it. Bad is that if you get an air leak, it can burn up the pump. Safest place is underwater....

 

[DAREDEVIL]

Good is that you can see it. Bad is that if you get an air leak, it can burn up the pump. Safest place is underwater....

The bad thing with this is , if the hose bust's while sitting at the dock u sink the boat.

And usually its coming from the pop off valve on top of the sea strainer,,so it should not do anything to the pump ?!

 

[CRC]

Well sh*t, now I have to rethink this but there isn't much time. If this is THE Brownie I have to give a lot of weight to that answer.:willy_nilly:.

 

[DAREDEVIL]

Well sh*t, now I have to rethink this but there isn't much time. If this is THE Brownie I have to give a lot of weight to that answer.:willy_nilly:.

It is THE Brownie !!!!! lol

and yes,,the man knows 100% more then i do,,BUT..if conected to a sea stariner i think it can't draw any air..and i would not want it below becasue of maybe hose issues ...but thats me..

 

[Smarty]

I discussed this a little here on another thread but now I have two questions. I will be installing my pressure relief valve and dump tomorrow. I plan to dump out the rear starboard side next to the bilge pump dump. Is there any reason not to go through the side and above the water line? (transom is fully cored)

My father installed the pressure relief valves on the Phantom in the exact spot that you mention, next to the bilge pump exit on the side(s) of the boat. He did that so he could look backdown the side of the boat while it was running above 45 mph and see if it was actually dumping water, the Phantom had an excessive water pressure problem which he solved after blowing a hose apart while running 86+ mph. He went through two different types of pressure relief valves to solve this problem. Good luck.

In the picture below (starboard side) you can at the very back of the boat on the side on exit is for bilge water (white ring), and the other exit is for excessive water presssure (white ring) behind the PhantiomV emblem. On the Port side is the identical outlets. The boat has two bilge pumps, and two pressure relief valves (twin engine boat). (Brownie knows way more than me, but I am not sure what pump will burn up when talking about pressure relief valves) The relief valve(s) do not have pumps for the Phantom pictured associated with the pressure relief valves in the set-up pictured, it is just dumping excessive water pressure.

 

[CRC]

My father installed the pressure relief valves on the Phantom in the exact spot that you mention, next to the bilge pump exit on the side(s) of the boat. He did that so he could look backdown the side of the boat while it was running above 45 mph and see if it was actually dumping water, the Phantom had an excessive water pressure problem which he solved after blowing a hose apart while running 86+ mph. He went through two different types of pressure relief valves to solve this problem. Good luck.

In the picture below (starboard side) you can at the very back of the boat on the side on exit is for bilge water (white ring), and the other exit is for excessive water presssure (white ring) behind the PhantiomV emblem. On the Port side is the identical outlets. The boat has two bilge pumps, and two pressure relief valves (twin engine boat). (Brownie knows way more than me, but I am not sure what pump will burn up when talking about pressure relief valves) The relief valve(s) do not have pumps for the Phantom pictured associated with the pressure relief valves in the set-up pictured, it is just dumping excessive water pressure.

Thanks much. I'm sure Brownie means that the raw water intake could suck in air at idle or maybe high trim positions if the relief valve became partially stuck open. I will make the decision soon. I need to do this tonight.

 

[Brownie]

Reggie burned a pump (and engine) in KW a few years ago. Sitting still, or idling is the most dangerous for ventilating. Not having an aggressive enough pickup is the danger at high speed.

 

[Smarty]

Reggie burned a pump (and engine) in KW a few years ago. Sitting still, or idling is the most dangerous for ventilating. Not having an aggressive enough pickup is the danger at high speed.

That makes sense in regards to ventilation for the external water pickup race boats. The Phantom I was referring has Bravo outdrives with low-water pick-ups. The suggestions to solve the excessive water pressure problem (suggested by Mercury Racing) were the the relief valves, or to plug up (close) two of the four water inlets on each lower. The relief valve is a spring loaded unit that is supposed to open at 40+ psi, pretty simple in design; the valves are installed in the bottom of the boat (below the waterline), and dump excessive water (pressure) above the waterline.

I was wondering what the high speed catarmarans did regarding excessive water pressure when they are approaching 150+ mph, and how that all works/is plumbed?