has a number of bilge
pumps. The discharge hoses loop high in the compartment and then discharge not far above the waterline. The trouble is, on a rough day, water
sloshing against the side of the hull
can be forceful enough to squirt water
through the discharge hose back into the bilge
. I know that check valves are sometimes used just upstream of the pumps but I do not consider this a good idea (reduced flow, air locks etc...). I assume that a vented loop will prevent a siphon problem but won't stop the forced water as I have described?
Is there any harm in putting a check valve just inside the hull
? The outgoing water is already on its way 'downhill' by then so it will have a very minimal affect on the discharge rate and the valve will prevent water from going the wrong way.