Hi Bridgeman:
Sorry you had a really, really bad day of it. I guess I will offer a few suggestions that I took after a bad day on the water in another boat I use to own.
1. Always install 2 bilge pumps one with a automatic float switch and both one size bigger then average size.
2. Check your through hull fittings like stated above or my personal choice is to splash the boat again and hang out for approx ½ hour then put the boat in gear at approx 1500 rpm and look in the bilge. You need to First make sure there is no water in the bow of the boat before you do the test by keeping the plug out back down into the ramp half way and make sure no water in bilge. On our variable dead rise boats some water will go up to the front of the boat when your boat is on your trailer even when you are on a flat surface.
3. If the vents are taking in water then you could seal them up by putting a thin piece of material between the vent and the hole in the hull.
I removed all 4 of my vents, but my reason was I didn’t like the looks.
Good luck you will figure it out.
FellowShip
………………………….
Just for the Grins
Official 23’ SF Antique Classic SeaCraft Owner