In our smaller boat we currently own we have an opening foreward center window and side windows in the Pilot house. The ventiallation is great, and at times too much, so we just crack it. However in our passagemaking boats, we had fully fixed pilot house windows. The ventillation was handled very well with 2 to 4 opening hatches on the pilot house roof. (May not work with a flying bridge!--but there are other ways to ventillate). We also had true Dorade boxes which had both the funnel scoops, the baffel boxes and both shutters on the inside and plates which could be screwed into the outside when the funnels are removed. The windows were 3/8" safety glass and withstood breaking waves and even a 90 degree roll, where the winows were under water. We had caulked them properly and they did not leak. The other boat had plexiglas windows and we removed these and put in lexan 3/8" which were overlaid over the fiberglass by at least 1 1/2" inches. Again no problem and leaks. The hatches were 12" x 12" up to 12" x 18". We had at least one facing foreward and one aft. This way, we could leave one open even when there was heavy spray. One could make a baffel box also to prevent spray during the heaviest of storms. There was a great breeze, even from a small 12" x 12" right over the helm seat--away from the electroncis. They were also small enough that a thief could not get thru them. Bob Austin