4 winns 99 245 sundowner deck drain help

[66mstgfsbk]

i have a 245 sundowner and in the rear corners of the deck is a drain, one on each side, they look like sink or shower drains. i was told these are scupper drains. i have rubber plugs that i put in the thru hull when i go in the delta, they came with the boat and never knew why till now. when it rains i pull the plugs out and water only comes out of one side. i tore the whole interior out just to look at these things, there is no check ball or rubber flapper its just a drain and the hose then connected to the thru hull. the thru hull sits above the water line about 1.5 feet when its calm and not underway. i have to fix the drain i found it broken and the hose was sitting in the cavity of the boat hull, i also found a bunch of water in the cavity. i still have to drain the water out but am wondering if i need a inline scupper or a flap type, or if the drain is a ok setup. i have to cut a hole in the floor but think i found a access panel that was screwed down and painted over. thanks again for the help.