I recently added a small West Marine Bilge Pro 600 to my H22.
The pump is mounted on a small metal plate and placed in the floor cutout just forward of the battery. A new floorboard was made with modifications to allow the pump to extend through the top. The 3/4 discharge line is run directly aft to a new thru-hull in the transom. The pump is wired to the electrical panel on the stbd side. Test frequently. Bilge pumps dont last long.