#55583, "RE: Fwd Staircase Dome covers 400 and 401" In response to In response to 3 Thu Oct-26-17 08:37 AMby Michael 400
Hi Bob and Henry,
thank you very much for your input regarding this issue.
Yes, the Titanic seems to have a porthole at the after end, port side. The 20 inch vent behind is identical on Olympic and Titanic. The black dot should be a porthole, it couldn't be part of the vent. The aft center ventilation of the dome cover is in the center, not in the black dot area, and there is nothing more in this area, so I am convinced about a porthole, or most problably two symmetrical portholes at the after end.
The arial photograph of Olympic, I assume from the 1920/30ties should have a porthole in the area of the ventilation hood, and the shutter inboard of it should be visible, so there seems to be no porthole there, and no shutter. If the shutter would be closed, it would be hidden by the vent cowl like the porthole, but then the dark sliding rails should be visible, which isn't the case. Between the 20 inch vent cowl and the side wall of the large stokehold vent there is a vertical black shadow before the white wall of the dome cover. It is a bit left of the center. It is too big to be a dark sliding rail of the shutter. With a high sun from aft/starboard, I think, it is the shadow of the rectangular aft center ventilation duct of the dome cover.
So, I agree to the evidence, two aft portholes Titanic, no aft portholes and no shutters Olympic. It makes sense, that Olympic had two portholes front, four on both side, and no aft, because the aft side is overshadowed by the funnel and stokehold vent. The evidence, that Titanic had quite the opposite configuration of only two portholes aft seems hard to understand, maybe they want to equalize the sunlight in the dome, so they omitted the front/side portholes in the sunlight area and added the aft ones on Titanic. Nevertheless evidence is evidence, and the differences between Olympic and Titanic are hard to understand in many cases.
So, thank you Bob, for your clarification.
Addition: Titanic: the dark vertical shade Henry mentioned is directly behind the black dot. For me it is the gap between the vent motor and the vent housing/cowl.
"Directly behind that gap, I can see the vent cowl nearly reaching the height of the dome cover. Behind that, there is a slight shadow of the vent cowl on the dome cover wall. Like all the 20 inch vent cowls it is open aft side." -> nonsense, see below, imagined shadows could be the vent housing, not the later installed and higher cowl.