You're welcome Legio.
That makes sense that the ice shield would only be used when coming into port. Normally, with the exception of bergs, ice is mostly around the coasts so they'd have to worry about it more when coming port, especially if it's a sheltered bay where the ice can collect.
When you look at the pics, you can figure out how the shield was attached and held in place. Quite simple actually.
Yes, probably hot water handy to warm him up and most likely the swimmer was coated in heavy grease of some sort to keep the cold away for a short time. Still, I wouldn't like to go overboard in the winter and underneath a (moving?) U-boat to make the connections.
Hmmmm, I've seen some before pics of a ringbolt in the stem of some U-boat, but not in others. Obviously not something that all of them had. The ringbolt was underwater, somewhere just below or level with the lower torpedo shutter. I wonder if that was only in northern boats and was the attachment point that this swimmer was diving down to connect the ice shiled to? It would make sense to keep it in place to have a bolthole there.
