Real Submarine Technology & History Q&A

[DaveyJ576]

Hello everyone!

The purpose of this thread is to discuss and explain actual submarine technology and history. It was felt that in order to keep game related threads uncluttered and easy to use, discussions related to real technology and history should be in a separate thread.

The deeply engaging and interesting gameplay of SHIV undoubtedly raises a lot of questions about the real world counterparts of the boats you play and this thread is aimed at answering those questions.

Suggested topics for this thread include (but are not necessarily limited to):

*How a real submarine works, how it dives, surfaces, maintains depth, shoots torpedoes, etc. Periscopes, radar, sonar, gun armament, hull types, auxiliary systems, engines, etc.

*Attack and defensive techniques.

*Life as a crew member of a submarine.

*Submarine Force history.

*WWII and the impact of submarine operations on the war effort.

If you have specific questions related to game play issues or mods, search the existing threads or create a new one. One of the experienced players will be happy to assist you.

I am a Chief Petty Officer in the United States Navy and a qualified submarine sailor. I served aboard the USS Darter SS-576 during the Cold War, a diesel boat very similar to the fleet boats played in SHIV. I am also the co-founder and author of a submarine history website.

In no way do I claim to be all knowing or all seeing. Therefore, I highly encourage anyone with information relevant to the discussion to contribute.

Okay, let's get started. Ask away !!

Dave

[Rockin Robbins]

Good. I'll lead off with a question that you might not be able to completely answer. In Clear the Bridge, Dick O'Kane mentions setting up the PK and when he's happy with the solution, he sets up for a constant bearing attack. He points the scope at the shoot bearing and turns the bearing crank backwards to stop the bearing. However the AoB keeps updating and the speed of course, remains the same. This way he can shoot as juicy parts of the target cross the wire.

All this implies that there was a direct connection between the periscope bearing and the TDC, such as modeled in the U-Boat for SH3 and SH4. In addition, Nisgeis has reported that such an automatic TDC input from the periscope did exist.

What do you know about all that? And do you know if it was there in WWII?

[ReallyDedPoet]

Nice idea for a thread Thanks for doing this.



Always great to hear from folks who are doing, or did this in real life, look forward to seeing
this thread progress. I am sure I'll have a question or two to ask at some point.


RDP

[DaveyJ576]

Originally Posted by reallydedpoet

Nice idea for a thread Thanks for doing this.



Always great to hear from folks who are doing, or did this in real life, look forward to seeing
this thread progress. I am sure I'll have a question or two to ask at some point.


RDP

I love this shot of the ol' Darter Maru. This one was taken not long after I left the boat. She is pulling into the Maebata Ordnance Facility in Sasebo, Japan were we were homeported. Notice that the forward torpedo loading skid is rigged up on the forward deck

Dave

[DaveyJ576]

Ric Hedman is the webmaster of our site www.pigboats.com. A third co-founder, Rick Larson passed away last year. Ric also has a tremendous companion site called Through the Looking Glass: A Photo Essay of Submarines 1900-1940, a link for which is on the right side of the main page. Check it out as well.

Both sites are non-profit and ad free.

Surf back to them often. New material is added as often as we create it!

Dave

[CDR Resser]

Thanks Dave. Looks like a great site. Can't wait to go through it in more detail.

Respectfully Submitted;
CDR Resser

[ReallyDedPoet]

Originally Posted by DaveyJ576

Ric Hedman is the webmaster of our site www.pigboats.com. A third co-founder, Rick Larson passed away last year. Ric also has a tremendous companion site called Through the Looking Glass: A Photo Essay of Submarines 1900-1940, a link for which is on the right side of the main page. Check it out as well.

Both sites are non-profit and ad free.

Surf back to them often. New material is added as often as we create it!

Dave

Those are some great links, thanks


RDP

[dangerclose]

Originally Posted by reallydedpoet

Whoa, nostalgia alert. I used to ride my bike up that mountain in the background. Well, at least to that lodge on the right side.

[DaveyJ576]

Great. A hard one to start off with! Thanks!

Anyway, you are correct. Based on electronic input from the gyro compass, there was an automatic input to the TDC from the scope. A dial on the TDC showed the bearing the scope was on.

Pre-war doctrine for torpedo spreads called for a seemingly unusual tactic. One fish would be aimed to slightly miss forward. One would be aimed to miss slightly aft, and one (or two depending on the size of the target) would be aimed to hit amidships. Why? Well, one of the hardest things to estimate, but extremely important to the firing solution is target speed. If your target is going faster than what you estimate, the fish will miss astern. If it is going slower than estimate, they will miss ahead. Aiming one a little forward an one a little aft eliminates uncertainty in target speed, virtually guaranteeing at least two hits out of three. But it also virtually guarantees that at least one, and maybe two of the fish will miss! Kind of a wasteful practice if you ask me. One way of reducing the uncertainty was repeated observations of the target so that your solution could be smoothed. The flip side to this (there is always a flip side!) is that you have to expose your scope more and thus have more chances to be sighted.

As training intensified after the war started, our skippers got better and better at estimating target speed by observing the bow wave generated by the target, and the sonar operators got better at counting propeller revolutions for speed estitmates. Dick O'Kane and his crew were masters at this and he aimed all his fish to hit. His constant bearing method was part of this firing doctrine.

Dave

[AVGWarhawk]

Originally Posted by DaveyJ576

Great. A hard one to start off with! Thanks!

Anyway, you are correct. Based on electronic input from the gyro compass, there was an automatic input to the TDC from the scope. A dial on the TDC showed the bearing the scope was on.

Pre-war doctrine for torpedo spreads called for a seemingly unusual tactic. One fish would be aimed to slightly miss forward. One would be aimed to miss slightly aft, and one (or two depending on the size of the target) would be aimed to hit amidships. Why? Well, one of the hardest things to estimate, but extremely important to the firing solution is target speed. If your target is going faster than what you estimate, the fish will miss astern. If it is going slower than estimate, they will miss ahead. Aiming one a little forward an one a little aft eliminates uncertainty in target speed, virtually guaranteeing at least two hits out of three. But it also virtually guarantees that at least one, and maybe two of the fish will miss! Kind of a wasteful practice if you ask me. One way of reducing the uncertainty was repeated observations of the target so that your solution could be smoothed. The flip side to this (there is always a flip side!) is that you have to expose your scope more and thus have more chances to be sighted.

As training intensified after the war started, our skippers got better and better at estimating target speed by observing the bow wave generated by the target, and the sonar operators got better at counting propeller revolutions for speed estitmates. Dick O'Kane and his crew were masters at this and he aimed all his fish to hit. His constant bearing method was part of this firing doctrine.

Dave

There was button (not provided in game) on the TBT and scope that could be pressed to up date the bearing correct?

[DaveyJ576]

Originally Posted by AVGWarhawk

There was button (not provided in game) on the TBT and scope that could be pressed to up date the bearing correct?

Correct

[LukeFF]

Dave,

In the "Through the Looking Glass" section of the website, there is a picture of what is said to be the S-42 fitted with what is obviously the slotted antenna of SJ-1 radar. Flanking it are what appears to be to S-18 subs, also with the SJ-1 radar antenna. Do you or your cohorts know when that pic was taken? I've pored through the patrol reports for the S boats and can't find any mention of SJ-1.

The pic in question is this one:

http://www.pigboats.com/subs/s42conn.jpg

[Pvt. Public]

how well could a sub mask its signature if it sat as close to the bottom as possible in water shallow enough? i understand that a sandy bottom wouldnt echo, but what if its really rocky? and somewhat related, has a submarine ever settled on the bottom to avoid detection?

[DaveyJ576]

Originally Posted by Pvt. Public

how well could a sub mask its signature if it sat as close to the bottom as possible in water shallow enough? i understand that a sandy bottom wouldnt echo, but what if its really rocky? and somewhat related, has a submarine ever settled on the bottom to avoid detection?

Yes, it has been done. The specially outfitted USS Grayback (LPSS-574) once sat on the bottom of Haiphong Harbor in North Vietnam while she sent SEAL teams ashore to do what SEAL teams do best. There have been other instances of bottoming, but contrary to popular image, this isn't done very much. In fact it is quite rare.

A submarine has numerous suction intakes along her hull that provide a source of sea water for A/C heat exchangers, lube oil and fuel oil coolers, trim and drain systems, etc. If you sit on the bottom, these systems have to be secured and the sea chest valves shut or you will draw muck, shells, rocks and lots of other crap into the system and screw it up. Bottom the boat with a slight down angle at the stern and you risk dragging the rudder and propellers across something that might damage them and that ends your day right there. The very ends of the boat at the forward and aft torpedo rooms are single hull sections with the pressure hull exposed. Hit a rock outcropping and puncture the hull here and you have massed quantities of water in the "People Tank", also a very bad thing.

In theory at least, the right bottom conditions can weaken or distort a sonar return. But the effect is minimal and a 312' submarine makes a huge sonar target in shallow water. Many sub skippers hesitated to conduct attacks in water less than 30 fathoms (180 feet) an only the really ballsy ones (like Fluckey and O'Kane) would conduct attacks in water too shallow to submerge in.

Dave

[CDR Resser]

Could you provide the web address of your website. Thanks for all your info.