My vents also let water in with spray. But that's only under more extreme conditions. About a week ago or so, I came back to my harbor and into wind and waves head on. Tons of spray came over the bow. No water in the compartment. I use to have a problem with the vents during rain storms while in the slip. I took some plastic pool cover and cut it to size and covered the vents. Bone dry ever since. The vents are not covered while out boating. So I expect some water might get in. But 10 gallons?
To me, 10 gallons is a lot of water. Is the water present before you leave the slip or only after you've been out on the water? When you spend the day on the water, how many times are you swimming and then get back into the boat? Do you just "drip dry" or do you towel off? With my boat being so old, I'm a bit paranoid about water in the boat and have a towel on the floor and another towel to dry myself to minimize water on the deck. If too much water gets on the floor, I towel that up too.
With my boat, aft of the window frames, the structure of the boat angles into the boat. So any water flowing aft from the window frames will channel the water back into the boat. This caused a lot of damage to my step/shelves and had to be replaced. I had to lay down some clear sealant aft of the window frames to channel it overboard.
Water can come in from everywhere! Don't just look at the obvious.