Discharge sea chests

[Pascal]

I wonder how much water can be pumped thru the sea chests on the hull sides without backing up. The holes aren't that big, about an inch or so. For instance in the port ER, the sea chest is used by the air con pump and the bilge pump. That potentially 5000 to 6000 GPH going thru that 1" hole. Similar problem with the port aft sea chest which is used by two deck drains and the bilge pump...

Has anyone enlarged these holes? Did Hatteras make them bigger later on?

[Cricket]

We removed our discharge sea chest, there was only 1 on our 50c.
What we did was to add dedicated discharge for both ER bilge pumps and then everything else drains via the transom.
AC dumps into both engine exhausts, port AC's and refrigeration via the port and stbd units via the stbd.
Everything else via a sea chest in the center of the transom that has an oblong hole with a half circle plate over the outside that's open on each end.
This way we can keep an eye on the bilge pumps and we also don't get any stains on the hull.

[Toolsntoys]

I like the idea of the bilge pumps having their own discharge port.

[Pascal]

I decided to install new SS 1 1/2" thru hulls for the aft and port ER bilge pumps. Already done the aft pump (about 12" forward of of the transom) and will do the ER tomorrow

I did a test in the port ER with a water hose in the bilge and with the AC pump running, the rule 3700 output was too much for the sea chest. I could see water backing up into the galley sink discharge hose.

I didn't test the aft discharge but I m sure that in an average Florida downpour the larger bilge pump would also be hampered by the flow from the drains

As much as I like the sea chest setup Hatteras used, the math doesn't add up... 1" deck drain plus 1 1/2" deck drain plus 1 1/2" bilge pump can't go thru a 1" hole...