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View Full Version : Why no periscope below 50 ft?


Capt Jack Harkness
06-28-17, 09:40 PM
I realize you won't see much with the scope head below the surface but there's no reason it would break from being too deep. In fact, more than one American sub actually got close enough to photograph submerged Soviet subs with the periscope.

ETR3(SS)
06-28-17, 09:46 PM
It is routine to have the periscope raised before ascending to PD to look for hulls in the water that may not have show up on sonar, like sailboats. So I second this.

ollie1983
06-29-17, 08:35 AM
Surely they would raise the scope prior to reaching the right depth to ensure that they exposed only the minimum of mast?

At what depth can the scope be used safely? I assumed the thing was proofed for the same submerged depth as the sub itself, or it is held inside a part of the sail which is pressure proofed externally?

Or for that matter what about the crew compartment on top of the sail you see them stood when surfaced? Does this close up or is it too sealed by doors etc?

Julhelm
06-29-17, 08:44 AM
It's for technical reasons.

Capt Jack Harkness
06-29-17, 11:31 AM
Fair enough. Something that applies to all masts, I assume?

tn_prvteye
06-29-17, 12:08 PM
Does the technical reason also cause the odd transition to above water/under water view? The engine can't display both at the same time, maybe? Not complaining...the techie in me is just curious.

jmr
06-29-17, 12:41 PM
Bummer to hear it can't be done because of technical reasons but I always liked looking through the scope in the Silent Hunter series and Dangerous Waters when about to surface and submerging.

https://youtu.be/EFPpb0qZNNk

Julhelm
06-29-17, 01:17 PM
Does the technical reason also cause the odd transition to above water/under water view? The engine can't display both at the same time, maybe? Not complaining...the techie in me is just curious.

That is correct.

ETR3(SS)
07-01-17, 10:13 AM
Surely they would raise the scope prior to reaching the right depth to ensure that they exposed only the minimum of mast?

At what depth can the scope be used safely? I assumed the thing was proofed for the same submerged depth as the sub itself, or it is held inside a part of the sail which is pressure proofed externally?

Or for that matter what about the crew compartment on top of the sail you see them stood when surfaced? Does this close up or is it too sealed by doors etc?
Typical procedure for ascending to periscope depth involves coming shallow, yet deep enough that you can't get hit by a fully laden supertanker. Raise the scope and then go on up to PD, the scope operator (most likely the OOD) will be scanning the sea surface on the ascent for anything that may be a collision threat that sonar couldn't pick up. Should he see something he can have the ships control party react to avoid a collision, usually an emergency deep. The periscope can be raised at any depth as it penetrates the pressure hull and can withstand the same pressure as the hull. Would be kind of silly to have a test depth that was greater than what your scope could withstand.

The bridge and lookout stations in the sail do have hatches, but that's for streamlining. The sail itself is a free flood area and so is exposed to sea pressure constantly.

caine007
07-05-17, 04:53 AM
What about breaking it at speed?

I can see the radar mast bending pretty easily, the scope looks fairly solid.

ETR3(SS)
07-05-17, 10:55 AM
What about breaking it at speed?

I can see the radar mast bending pretty easily, the scope looks fairly solid.Haven't tested this myself, but there is a speed limit for the masts with and without the fairings raised. Also, Julhelm if you're still lurking this thread: the radar masts are very high. Any particular reason for this? Your resources are what I would consider excellent so puzzled at this.

Julhelm
07-05-17, 11:29 AM
I assumed they would raise to the same height as the periscopes. Also the 50ft depth is hardcoded which gave me problems with certain boats like the Permit.

ETR3(SS)
07-05-17, 12:51 PM
Typically radar on submarines is/was used for contact management during inbound/outbound transit. Therefore raised height wasn't very high as it didn't need to be. I understand your constraints regarding periscope depth though, particularly with the Permit as she had a much smaller sail.

Shadriss
07-07-17, 03:53 PM
I'm gonna second ETR3's descriptions - he's about as accurate as he's allowed to be, assuming his name is his actual Rate (STS1/SS myself, for the record). My guess is that they aren't using "keel depth" for their references, since when surfaced the depths are showing single digits. Makes me think they might be using center-line depth, which is just flat silly.

What strikes me as really odd is that the depths involved in PD aren't exactly hard to come by - just watch a few older submarine specials and they show the whole process.

Capt Jack Harkness
07-07-17, 07:36 PM
Huh, I just assumed it was depth below keel...

Shadriss
07-07-17, 07:39 PM
It should be... but it isn't. A 688 on the surface has a keel depth of about 26 - 30 feet, depending on how much water it has in the variable ballast tanks. In game, it shows something like 6 feet. Definitely not keel depth.

ETR3(SS)
07-07-17, 11:02 PM
I'm gonna second ETR3's descriptions - he's about as accurate as he's allowed to be, assuming his name is his actual Rate (STS1/SS myself, for the record). My guess is that they aren't using "keel depth" for their references, since when surfaced the depths are showing single digits. Makes me think they might be using center-line depth, which is just flat silly.

What strikes me as really odd is that the depths involved in PD aren't exactly hard to come by - just watch a few older submarine specials and they show the whole process.
Yep that's my rate, striker turned radioman. Spent most of my time pushing sticks before ending up on ESM, WLR-8. Qualified the watch without seeing a single contact!:haha: Then we get CSS-17 CoS on board in PH and all hell breaks loose on my watch.:doh:

Shadriss
07-07-17, 11:53 PM
CSS 17 - makes you a Bangor SSBN boy, especially paired with the WLR-8. Served on a few boats out that way, specifically the MICHIGAN (SSBN days, pre-conversion) and the ALABAMA. Nice enough area, but glad I'm done with it... I'm on terminal leave ATM, so it's all still fresh enough to be painful.

Of course, with you being a striker, that likely means you are about to be out or have been out a while yourself - haven't had those in the SS fleet in 15 years or so, as I recall.

EDIT: Just saw your signature. One of those KENTUCKY bastards. I spent more time fixing that boat when I was working for IMF... not as much as on the HMJ, of course, but a lot. :)