Naval History Forums

Hi guys. Another detail, the Sight Reduction Tables that every ship equipped for celestial navigation has onboard, can be used to calculate great circle paths. No need for manual solving of spherical trigonometry.

https://upload.wikimedia.org/wikipedia/commons/thumb/7/78/Admiralty_Chart_No_132_Gnomonic_Chart_of_Indian_and_Southern_Oceans%2C_Published_1914.jpg/799px-Admiralty_Chart_No_132_Gnomonic_Chart_of_Indian_and_Southern_Oceans%2C_Published_1914.jpg Can you send me the original image file? Thank you! Sur...

Wonder how many of these questions have known answers -- There were seven DF stations in Great Britain in 1941? At what lat-lons? How accurately did they measure the azimuth of an incoming signal -- plus or minus how many degrees? Did the accuracy decrease if the signal had crossed Ireland? Did som...

OpanaPointer wrote: ↑Mon Jul 22, 2024 11:04 pm

marcelo_malara wrote: ↑Mon Jul 22, 2024 5:47 pm

OpanaPointer wrote: ↑Mon Jul 22, 2024 5:45 pm No bomb load or bombs unarmed?

Ferry flight.

A full load would have been ... exciting.

For sure, the Empire States may have come down like its twin cousins about 80 years later.

The example that in my opinion better illustrates the difficulties for an Uboat in attacking a ship is illustrated by the attack of U108 on the auxiliary cruiser HMS Rajputana (https://uboat.net/allies/merchants/ship/876.html). On April 11th 1941 the cruiser was patrolling in Denmark Strait, sailing...

In WWII a B-25 (IIRC) flew into the Empire State Building. Cause a stir until it was confirmed to be a friendly. Yes, a navigation error. The pilot was flying south over East river in low clouds. He was counting the bridges he saw below in order to ensure being south of Manhattan to turn west to Ne...

After some more reading, looks like the actual ASDIC range was more like 2000 m. However, such a U-boat would have to be large and would probably be detectable at a greater range. I think good fire control could be created, but I'm not sure about stabilization. In any case, not an easy thing to do....

In WWII a B-25 (IIRC) flew into the Empire State Building. Cause a stir until it was confirmed to be a friendly. Yes, a navigation error. The pilot was flying south over East river in low clouds. He was counting the bridges he saw below in order to ensure being south of Manhattan to turn west to Ne...

Hello. Thanks for joining. I was thinking about using these boats as a part of a wolfpack. Their primary purpose would be to attack the escorts rather than the merchants. The idea is to decrease the pressure on the normal U-boats, create chaos and give the escorts something to worry about as a typi...

If there was ever a useless piece of equipment in military history it was the...submarine gun. The submarine round hull makes her an easily rolling ship, the guns had no stabilization, the deck is so low in the water, ammo needed to be manhandled. Then someone came with the idea of an enclosed subma...

You have to balance the form resistance, the area of low pressure behind any moving body immersed in a fluid, and which depends on cross section, with the friction drag, which depends on wet surface, and itself depends mainly on length.

StanS wrote: ↑Fri Jun 28, 2024 7:37 am
Interesting. However, isn't a torpedo the optimal underwater shape? It is also long and narrow.

As a perfect cylinder yes. But it would be better being shorter and fatter. The Type XXI is double the displacement of a Type VII, but the XXI is just a little longer, whereas she is beamier.

Would anyone know of a complete listing of all ships sunk and those damaged (both Allied and Japanese), during the Guadalcanal campaign? And the cause eg surface action, aircraft, submarine etc. From 7 August 1942 to 9 February 1943 inclusive. I've seen mentioned in various books numbers that range...

It is possible that the Type VII was too narrow and too long, for surface riding, whereas submerge resistance depends mainly on surface friction, and this depends on wet surface. To illustrate the point: -suppose a cube, 2m each side. Its volume would be 2 * 2* * 2 = 8 m^3. The surface of its 6 face...