Seems a waste to let the priming hole evacuate water back into the boat. But maybe that is what has to happen? Would it make sense to use a 1/16th hose from the priming hole and have it go into the main discharge line (like a Y bracket)? Would it cause turbulence or some other reason not to? In the past I have angled the priming hole to keep the ECS cool or the motors, but thought I would ask this group. Lou
Lou; I think that sending the water from the priming hole anywhere that it is the restricted in any way defeats the purpose of the priming hole which is to expel any air that is preventing the pump from sucking up the water. The impeller can some time become "air bound" with water in the discharge tube and can not pump enough air pressure to pump the water sitting in the discharge line out and then the air so it can again pump water. Turning off the pump can sometime clear the problem as the water in the discharge line falls down through the pump and clears the discharge line.
I'll take a small loss for priming over an unreliable pump any day! I've had several sinks from a lack of priming.
I forgot to bolt my pump together before a battle a few months ago. The bolts were in but no nuts on. No priming issues that day. If you route a line from your priming hole to anywhere you run the risk of vapor locking your priming hole. Best to keep the bore short and clear.
If your pump doesn't prime easily you need to look at the case design. Is the outlet positioned to capture air around the impeller? The sooner the outlet turns upward (with no downward areas), the better the priming. The outlet should be as close to the centerline as possible so heeling doesn't promote air entrapment in the pump case and outlet line. If your ship always sinks one end first, position the outlet towards the end that sinks last.
