Question on weather, history, and GWX

[Aktungbby]

...at periscope depth; when the exec would do a meticulous 360⁰ with the observation scope to look for any air/sea subhunting threats...

[theworldover]

Originally Posted by Aktungbby

...at periscope depth; when the exec would do a meticulous 360⁰ with the observation scope to look for any air/sea subhunting threats...

So that’s it? No idea whether it’s calm or a hurricane until you look at it in the periscope?

[Aktungbby]

Originally Posted by theworldover

So that’s it? No idea whether it’s calm or a hurricane until you look at it in the periscope?

...basically you look first, no matter the weather; particularly at the sky for inbound-low-level 10-centimeter radar equipped PB4Y-1 Liberators et al(like my late Uncle Bob did) using a weatherfront as cover with 4 depth charges set to straddle your boat.. set on shallow to damage crash diving subs. The weather is a distant secondary issue to mere survival. And, in real U-boat life, the use of the extended wider-view observation scope precludes exceeding 3 knots when submerged to avoid vibration(and periscope's wake) of the scope's tube risking moisture and fogging, forcing a probable trip back to base! https://www.uboataces.com/periscopes.shtml

Before a U-boat breaks surface, the skipper would scan the horizon at periscope depth, searching for hostile units which could pose a threat. Only when its clear, the U-boat would surface, led by the watch officer, the crew would rush into positions on deck.Periscopes suffered from two main problems, the most important was vibration. When fully extended, the long unsupported tube created turbulence on a moving U-boat. At 6 knots, it caused excessive vibration which rendered it almost impossible to use. This was dampened by using an extension bracket to reduce the unsupported length and the pointed end was redesigned to minimize the forward hydrodynamic resistance. Nevertheless, vibrations still occurred, but to a much lesser degree. The other problem was fogging of the lenses. Since the damp atmosphere of the U-boat caused fogging, it was especially important that the tube was not only watertight, but was airtight as well. Any fracture on the airtight casing caused by a depth charge attack would result in fogging of the tubes.

https://warfarehistorynetwork.com/ar...bay-of-biscay/ https://en.wikipedia.org/wiki/Battle_of_the_Atlantic