Those plugs are supposed to remain closed. I had the unfortunate experience of forgetting to close them once, by the time I realized that they were open, water was pouring in up through the centerboard trunk. When I went to reach off the back of transom to close them, I accidentally knocked one off and it sank.... Needless to say it was a slow, wet sail back to the ramp were I had to pull the boat out of the water and let it drain.
Luckily I was able to buy replacement plugs from soundboatworks.
After sailing this boat quite a bit I have noticed that even when the plugs are closed and the boat empty, the boat does accumulate some water in the hull only up to a certain point. I'm sure this is the ballast you are referring to.
I have been sailing this boat for a while now and have made numerous repairs and improvements so if you have any other questions or anything let me know!
