My Catalina 25 came with a factory-installed Whale manual pump routed out the transom (above the waterline).
To which I added---per Don Casey's writings---a second electric pump w/high capacity, installed a couple of inches above the intake for the manual one.
After contemplating the location for the Rule pump's discharge point---a second through-hull, a Y connection to the existing through-hull---and with the help of several SailNet suggestions, I decided to discharge the backup bilge pump into the cockpit, right about ankle level, and let it empty through the transom scuppers.
The reasoning? If/when the secondary leaps into action, it gets my attention right away.