I'm not sure how your '79 cockpit drains are plumbed but our '78 has a ,for lack of a better term, fiberglass manifold glassed underneath of the cockpit on each side. The forward and aft cockpit scuppers dump directly into this contraption and there's a port...correction... a hole on the side where the hose from the respective sides of the cockpit hatch drains get shoved into this manifold thing. From there, there's a fitting on the lowest part on the manifold thing that is plumbed into the scupper drains on each side of the cockpit. I really am not fond of this arrangement Mainship came up with & maybe yours is different.
When I get time, I will eliminate the cockpit hatch drains being plumbed into this system. The old generator port is unused so I have a plan to drain the cockpit hatch ports into the ex generator exhaust overboard port.
I don't know if it'll happen this year or not ,though.