One of the things I need to address on my 227 are several original thru-hulls. The previous owner had all but the ones for the forward bilge pump, aft bilge pump and port helm drain replaced w/in the past few years, so I'm only addressing these three now. The sizes of the current ones are 3/4" for both pumps and 1" for the helm drain. The forward and aft bilge pumps are the standard 800 gph Rule pumps and althought they both work, I want to replace them in the near future as I don't know how old they are. That got me thinking about pump and discharge sizes.
Forward Bilge
Due to space limitations, I am limited to a pump with height of about 4". From what I have seen, the largest pump Rule offers that would meet this height requirement is 1100 GPH, with an 1-1/8" outlet.
Aft bilge
I forgot to measure how much clearance I have between under the 470's oil pan, but from feeling around in there, I believe I have plenty of room to mount a 1500 or 2000 GPH pump (also w/ a 1-1/8" outlet).
For a wet slipped boat, I think I would probably stick with the 800 GPH pumps fore and aft, and run a 1500 or 2000 backup aft pump. That way, there wouldn't be much battery drain for keeping up with things like rain water that gets in around the engine box when the boat was unattended. But, given that I'll be on the boat 99% of the time it's in the water, I'll know if there's a problem so don't have to worry about unattended battery drain. So, I'm kind of thinking I should plan to go with the higher volume pumps fore and aft with the 1-1/8" discharge, no backup pump, size my new thru-hulls based on this and just use some hose adapters until I replace the pumps? Does that sound like a good idea or would this be "over pumping" the boat...if there is such a thing?
Forward Bilge
Due to space limitations, I am limited to a pump with height of about 4". From what I have seen, the largest pump Rule offers that would meet this height requirement is 1100 GPH, with an 1-1/8" outlet.
Aft bilge
I forgot to measure how much clearance I have between under the 470's oil pan, but from feeling around in there, I believe I have plenty of room to mount a 1500 or 2000 GPH pump (also w/ a 1-1/8" outlet).
For a wet slipped boat, I think I would probably stick with the 800 GPH pumps fore and aft, and run a 1500 or 2000 backup aft pump. That way, there wouldn't be much battery drain for keeping up with things like rain water that gets in around the engine box when the boat was unattended. But, given that I'll be on the boat 99% of the time it's in the water, I'll know if there's a problem so don't have to worry about unattended battery drain. So, I'm kind of thinking I should plan to go with the higher volume pumps fore and aft with the 1-1/8" discharge, no backup pump, size my new thru-hulls based on this and just use some hose adapters until I replace the pumps? Does that sound like a good idea or would this be "over pumping" the boat...if there is such a thing?