Yeah rokket, the air blast does seem a bit odd, but it wouldn't be the first oddity we've found with U-boats. And it does seem to fit the available, though scanty, evidence as to how they worked.
billp, glad you've found the cherry wood strips of interest. I've used them in dozens of ship models and even for building parts of land-based dioramas. They're very versitile.
Not sure when I can get pix of my own build. Besides having terrible computer problems for the past few months, the only digital camera I have is my cell phone which isn't the best resolution. Not sure how much detail will show up with it.
I had a big set back last week too. I have a box with all the little parts that I've been scratch building and dry fitting to my U-boat, and all the parts that I've cut off the sprues but haven't glued in place yet. Well, the box fell over last week and spilled about 300 parts all over the floor. It's going to take a while to even go through and figure out if I've found all of them or if I have to order/create more parts. (There were a few choice words uttered, and the cat thought it looked like great fun!)
On a positive note though, I figured out how to make the the capstan spring-loaded so that it can be displayed in either the above or below deck position. It's a variation on what I was planning to use to raise and lower the bollards. While I don't think the capstan actually went up and down (I think they unbolted manually and stowed it - but if anybody has any better info I'd be interested), however, since I don't like the idea of making it removable and therefore, loseable, this is a good method and will look right even if it's not how the original worked in RL.