Had a similar problem on my 281
Fixed all but the portlite over the chart table by cleaning out the caulk on the outside where the 2 aluminum pieces meet. Once the caulk has been removed, just in the slots between the two pieces, recalk them with silicone sealer. This is definitely the easiest, first step. On the one that Still leaked, I replaced the inside gasket. It is not hard but it is tedious getting the old gasket and all the sealer out of the channel. I used a sharp knife, small flat blade screw driver, and dental picks. If you need to identify your portlite sizes or need a source for ordering gaskets, let me know. I have all that info around here somewhere. I think I have an extra gasket that fits the portlites over the chart table and the galley.Good luck