Author Topic: Periscope on E-Bay  (Read 545 times)

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Rodolfo Peirano

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« Last Edit: January 13, 2018, 05:25:02 PM by Rodolfo Peirano »
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Rafael Chamon

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Re: Periscope on E-Bay
« Reply #1 on: January 13, 2018, 11:01:05 PM »

Rodolfo, thank you very much for your interesting reference to the periscope in e-Bay.

Excerpted from the book "Introduccion al estudio de los instrumentos ópticos" by Pedro Jiménez-Landi:

The submarine periscope presents remarkable challenges of optical and mechanical design and for that reason it is one of the most expensive optical instruments due to its exceptional characteristics.

Its length must cover the depth of observation that can reach 14 meters and this requires numerous lenses, some displaceable, designed to accommodate the rays in a relatively long and narrow tube. The apparent field and the magnification can be changed according to two modes: one for observation and the other for attack, with an apparent field of 50-70º and a magnification of 1.5 for the observation mode, and a narrower  field and greater magnification for the attack mode.

The head of the periscope that emerges on the surface of the water is mounted in a narrow tube about 50 cm high and 4 cm in diameter so that when the submarine advances, it does not reveal to the enemy its situation by the wake it produces. This tube widens progressively below, forming a tube of considerably larger diameter. This tube must be manufactured with great precision so that it can move up and down and rotate around its axis at any height without the pressure of the water at 14 meters immersion causing it to penetrate water through the closing joints and maintain tightness in any position.

Also, while the submarine is immersed and moving forward, the tube must overcome the resistance of the water without experiencing the minimum bending that would result in a de-centering of the entire optical system if the straightness of the optical axis is not maintained. Nor should we forget that the tube material must be high quality stainless steel because the contact with seawater.

Cheers

Rodolfo Peirano

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Re: Periscope on E-Bay
« Reply #2 on: January 14, 2018, 01:31:57 AM »
Dear Rafael,

Quote
Also, while the submarine is immersed and moving forward, the tube must overcome the resistance of the water without experiencing the minimum bending that would result in a de-centering of the entire optical system if the straightness of the optical axis is not maintained. Nor should we forget that the tube material must be high quality stainless steel because the contact with seawater.

I would add that in the construction of the periscope, to avoid, during sea navigation, any twisting of the structure, the external tube was wrapped with steel cables rolled around the periscope. (see image)

Dear cheers.
Rodolfo
 
everyone can learn from everyone - Rodolfo

Rafael Chamon

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Re: Periscope on E-Bay
« Reply #3 on: January 14, 2018, 02:09:51 PM »
You can find more information on a modern submarine periscope in this "Submarine Periscope Manual":

https://maritime.org/doc/fleetsub/pscope/index.htm

Cheers.