Peter,
On my '78 the floor scuppers were thru the transom. The only time I would get any water back up thru them were if I had two fatazz fishermen standing in the aft corner and I was anchored up. Here is a couple of old shots showing the two drains thru the transom adjacent to the trim tabs.The 2nd pic shows the port side PVC drian coming out of the floor cup and 90* out the transom. I added the "T" piece which was a tie-in for the old gutter system around the battery/floor deck hatch in front of the splashwell.
I'm not trying to convey anything here right or wrong other than this was the system setup that was on my 23'without a raised floor.
