Need input from some of the experts. We have a 1988 Catalina 30 (hull 5075). I want to make sure the holding tank vent opening is clear where it exits via a port-side stantion. In looking at the stantion, I see two small holes. One is about 1-1/2 inches above the base of the stantion and the second is somewhat smaller and around an inch or so below the top opening. Both open to the outside. Here's my "issue." It seems that neither of these small holes is open. The lower one (which I think is probably supposed to be the vent opening) is totally rusted shut. (Okay, it makes me feel better to think of it as rust). Is that the opening? If so, then I assume I can just drill it out and proceed from there. What's the upper hole for? Is it also supposed to be open? Two good things: first I have NO disagreable boat or head odor at all. This is just a maintainence operation so I can stay ahead of things like that. Second: I have Peggy's book (thanks Peggy. I bought it from you during Pacific Sail Expo) Regards, Gary Kunkel