Finally getting to spend some time in my boat and realizing I have airtight hatches. I built the Vaclav style hatches with the Leidy bungies and am afraid its so air tight that with temp changes my boat is going to implode. I am not excited after succeeding in getting my hatches to be water tight to drill into my bulk heads. Any recommendations on the best way to do this? Can I fill the hole with something that is water tight but not air tight? Cork or valve? Any info much appreciated. For what its worth the boat is a CLC west river 180 with a strip built deck and okeme hull and bulk heads glassed in and out. Thanks, Todd