raw water strainer

[Sointu II]

Hi,

I just changed the raw water strainer as the old one was damaged. I mounted above the water line and it seems to work. The incoming pipe is full of water but the pipe to the water pump has air in it. I am now worried about the cooling.

If the strainer is below the waterline you need to turn the water cock off eveytime you leave the boat. If it is above the waterline you can leave the cock open but is the water cooling with bubbles adequate ?

The Hunter manual does not give enougth detail on this point. What is your experience on this ?

 

[Paul F]

Installed mine below the water line and close the intake valve when not in use. If you create a siphon with an airtight water flow, which you have unless there is a vented loop, the intake is the same as having the strainer below the water line. When the pump is running the air in the line will quickly be pumped out and will not harm how the engine is cooled.

 

[Benny]

Raw water strainers are usually located below the waterline to insure proper water flow and avoid the possibility of air leaks which could interrupt flow. The intake cock is there to shut the flow when needed and that is its job. We inpect our hoses periodically and replace all doubled clamps once a year; we are confident on the integrity of our through the hull plumbing and feel no need to shut any off everytime we leave the boat. Those strainer cups have an "O" ring which hold water pretty well but I don't think they were designed to hold out air. Any interruption in water flow will burn your impeller and cause the engine to overheat, in that order.