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Old 02-03-09, 02:52 AM   #31
LukeFF
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Good catch there, Dave. You're right it doesn't look like Dutch Harbor at all and most likely Milne Bay. That would put the time of the picture and the one immediately above it to any time from 19 March 1944 onwards.

Those two S-18 boats are indeed a mystery. The longest a "20-something" S boat remained in combat service was the ill-fated S-28, which terminated her last patrol in October 1943, yet she eventually went on to Pearl. I've not read of anything that says she put in training time at Milne Bay. We'll probably never know the ID of those two boats, sadly.
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Old 02-03-09, 08:20 PM   #32
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Here's a weird one I've always wondered about: When operating in Arctic or otherwise cold conditions, can you feel the difference in temperature while submerged. IE: Through the hull, the ballast tanks, and other insulating stuff.
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Old 02-04-09, 12:01 AM   #33
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DaveyJ576 wrote...
Quote:
Rules?! In a submarine??!!
During the 60s when I was on a diesel boat the uniform of the day on the Carp when we were at sea was shorts, t-shirt and sandals. A few of the crew had earrings and hair was definitely longish by navy standards. Back then sub sailors were the only ones in the navy who could have beards and moustaches and we were also the only enlisted men who could wear civilian clothes off the boat when we were overseas. I remember one weekend in San Juan around 2AM or so the captain brought a woman of very questionable morals back to the boat and she spent the rest of the night in his cabin. Where else in the navy could a lowly seaman get drunk in a bar with the captain.
I had the best %#@?&! time on subs as an 18yr old kid.
Reading the stories on that site that Dave linked to, I knew a bunch of those characters and I lived in Bells when we weren't at sea. Ah, great memories.

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Old 02-04-09, 12:51 AM   #34
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Quote:
Originally Posted by DaveyJ576
Quote:
Originally Posted by Pvt. Public
-snip-
-snip- 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.

-snip-
Dave
Had to stop and say thanks for saying "People Tank" I haven't heard that term in far to long.

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Old 02-04-09, 10:20 AM   #35
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Quote:
Originally Posted by Captain Vlad
Here's a weird one I've always wondered about: When operating in Arctic or otherwise cold conditions, can you feel the difference in temperature while submerged. IE: Through the hull, the ballast tanks, and other insulating stuff.
When running on the surface in northern waters, the boat will get very cold. The main engines draw a lot of air through the boat. I remember many times having to wear a foul weather jacket while on watch in the control room.

But, once you secure the engines and pull the plug, the boat will get very warm. There are a lot of sources of heat inside: electrical systems, batteries, still warm engines, radar, sonar, 80 bodies, etc. While submerged there is no place for the heat to go as no air is exchanged with the outside. What cold that is radiated inward from the hull is quickly negated by these heat sources.

The major problem in northern waters is condensation. The increased heat loads and humidity levels lead to heavy condensation on the cold hull. This condensation then drips into everything, the biggest problem being fires from electrical shorts. The S-boats operating out of Dutch Harbor suffered terribly from this problem. There was cork insulation placed in many areas, but this didn't help much.

This is were air conditioning comes in. Contrary to what some people think, the A/C systems were installed primarily to control humidity levels and reduce condensation, not for crew comfort, although this was a happy side effect. This was a HUGE benefit and it greatly increased reliability in electrical systems and thus resulted in much higher operational readiness.
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Old 02-04-09, 04:00 PM   #36
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Good information, links, pics and stories! Thanks!
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Old 02-04-09, 05:12 PM   #37
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Quote:
Originally Posted by DaveyJ576
When running on the surface in northern waters...*snipped for brevity*
Ah, thanks. Like I said, I was curious, and sometimes when writing stories and such I wondered if alluding to the temp would be appropriate.
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Old 02-05-09, 07:28 AM   #38
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Hi Dave,

Do you know what shape the Main Ballast Tanks No. 1 and No.7 that are part of the forward and after torpedo rooms were internally? The drawings in the fleet boat manual has them shown as a U shaped tank, with the outer sides being rounded and the top and middle sections being flat plates, the upper two parts of the U forming the deck of the torpedo rooms. This doesn't seem like a very good shape to withstand pressure, from an engineering point of view as they have large flat surfaces and sharp angles in the corners. There is no signs of any extra thickness in the pressure hull at the top/deck of the torpedo room to compensate for this shape.

Are the fuel ballast tanks actually built as a U shape, with flat sides to the pressure hull?

Also, after having a look at the pictures of the sections being constructed before assembly, it appears that the bulkheads are a single sheet welded at the ends of the pressure hull. Were the bulkheads made to fit inside the pressure hull, or were they the same diameter as the pressure hull. IE, when two sections were joined was it pressure hull - pressure hull, or was it pressure hull - bulkhead - pressure hull?

I also have a question about Normal Fuel Oil Tank number one. Was it completely sealed externally, with only valves to drain and fill from the inside in the forward topedo room? Even the fuel filling lines seem to be routed throught the torpedo room, so were there any hull openings at all through the pressure hull where Normal Fuel Oil Tank number one is?

Finally, how thick are the dividers between the ballast tanks? The drawings seem to indicate that they are fairly thick - were they?

Oh yeah I almost forgot. The conversion process for Fuel Ballast Tanks to Main Ballast Tanks was to remove some blanking plates - I'm assuming these were over the vents, as you wouldn't be able to replace ones over the flood ports at sea. The question is why have blanking plates - were the vent valves not secure enough?

Thanks for reading!
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Old 02-05-09, 08:33 AM   #39
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Quote:
Originally Posted by Nisgeis
Hi Dave,

Do you know what shape the Main Ballast Tanks No. 1 and No.7 that are part of the forward and after torpedo rooms were internally? The drawings in the fleet boat manual has them shown as a U shaped tank, with the outer sides being rounded and the top and middle sections being flat plates, the upper two parts of the U forming the deck of the torpedo rooms. This doesn't seem like a very good shape to withstand pressure, from an engineering point of view as they have large flat surfaces and sharp angles in the corners. There is no signs of any extra thickness in the pressure hull at the top/deck of the torpedo room to compensate for this shape.

Are the fuel ballast tanks actually built as a U shape, with flat sides to the pressure hull?
Wow! Will asked a pretty good question that I will have to answer in a couple of parts. Here is part one:

On the Gato and Balao class boats, the pressure hull was not a perfect cylinder. In order to accomodate the necessary tankage in the forward and after ends of the boat, the designers were forced to radically alter the shape of the pressure hull to accomodate the tankage. Thus, the pressure hull had several kinks in it at the ends. Obviously this was not an optimal situation from an engineering point of view, but it still worked pretty damn well.

MBT #1 was u-shaped and this was done to create a "pit" under a removeable deck in the forward torpedo room. This allowed access to the lowest torpedo stowage racks and provided some stowage for torpedo handling gear. When you were in the pit, you were standing on the pressure hull. MBT #7 was flat topped.

All main ballast tanks are always either completely full or completely empty. Thus, their structure on three side does not have to resist sea pressure. Only the fourth side does and this will be part of the pressure hull. In the case of MBT's 1 & 7, the pressure hull portion of the tank formed the deck you walked on in the torpedo rooms. In other words, the top of the tank was also the bottom of the pressure hull. All other MBT's were in the void space between the inner pressure hull and the outer hydrodynamic hull amidships. A cross section of the hull would make these tanks appear like giant U's, but in reality they were divided into two separate tanks at the keel.

Open flood ports at the bottom let water into the tanks when vents were opened at the top, allowing air that was holding the water back to escape. MBT's #1 & 7 were located under the pressure hull and did not extend up the sides of the hull like the other MBT's. The problem here is that there was no place to put the vents! The solution was to attach large vertical pipes (called risers) to the outboard sides of the tank inside both torpedo rooms. The risers ran upwards through the rooms and out of the top of the pressure hull into the superstucture. Vent valves were placed at the top end of these riser pipes. Once the vents were opened, the air in the tanks would vent through the risers and the tanks would flood.

This was not an optimal design because when the boat was submerged, you had full sea pressure inside these riser pipes, which were inside the pressure hull in the torpedo rooms! Any damage at all to these risers from depth charge attack and you had a big flooding problem really fast (water in the "people tank" = very bad).

As with any problem, there was a solution. The subsequent Tench class boats had their tankage re-arranged. MBT #1 was moved forward so that it could vent directly overhead, eliminating the risers from the forward torpedo room. MBT #7 was found to be redundant and was converted to a variable fuel oil tank.

For a visual representation of what I am refering to click here:

http://www.maritime.org/fleetsub/app...es/figa-04.htm

And here:

http://www.maritime.org/fleetsub/chap4.htm#4A

Scroll down to figure 4-1 and you will get an idea of what I am talking about.
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Old 02-05-09, 10:25 AM   #40
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Quote:
Originally Posted by Nisgeis
Are the fuel ballast tanks actually built as a U shape, with flat sides to the pressure hull?

Oh yeah I almost forgot. The conversion process for Fuel Ballast Tanks to Main Ballast Tanks was to remove some blanking plates - I'm assuming these were over the vents, as you wouldn't be able to replace ones over the flood ports at sea. The question is why have blanking plates - were the vent valves not secure enough?
Okay, part two.

Fuel ballast tanks are a U-shaped, but the side that is against the pressure hull is not flat. It is contoured to match the curvature of the hull.

The necessity of having long range in the fleet boats really drove the design of the boats. In order to achieve the long ranges needed to conduct Pacific patrols, a vast amount of fuel needed to be carried. The voids between the inner and outer hulls provided excellent storage areas for fuel.

The problem that arose was one of compensation. Fuel oil has weight. As you burn fuel the boat gets lighter. If you burn enough fuel, you would eventually get to the point were you would be so light that you couldn't submerge. So, all the Normal Fuel Oil tanks are compensated with sea water. As fuel is used, water is let into the tanks to make up weight for the used fuel. Fuel floats on water so your fuel suction is at the top of the tank.

But now the exact opposite situation occurs. If all of the fuel tanks were set up like this, eventually you would get so heavy that you may not be able to surface! The solution was ingenious. A portion of your fuel tanks were made into a combination of fuel tank and ballast tank. Once the fuel was used up, you could convert the tank into a Main Ballast Tank which could be blown or flooded like any other MBT.

A Fuel Ballast Tank (FBT) has many of the same features as a MBT. It is shaped the same, it has flood ports at the bottom, and vent valves at the top. It has blowing connections so that it can be blown with high pressure air to surface the boat. Because it carries fuel for part of the voyage, it has some major differences too. Of course it will have suction lines at the top so that fuel can be drawn off as needed. However, unlike an MBT, an FBT has valves at the bottom that will close off the flood ports. This prevents a loss of fuel when the tank is full due to the rolling and pitching of the boat in heavy seas. A FBT also has a sea water compensation system to make up for fuel useage.

Once all the fuel in the tank is used up, converting it to a MBT is fairly simple and can be done at sea by the ship's crew. The flood valves at the bottom are opened and locked in the open position for the remainder of the voyage. Vent valves, which had their operating mechanisms disconnected to prevent accidental opening, are reconnected to the system. The vent valves themselves are located outside the pressure hull in the superstructure. Blank flanges are placed over these vents to prevent them from being unseated during a depth charge attack. If this happened on an MBT it was no big deal. If the vent became unseated on a FBT fuel would leak out through the vents (remember fuel floats on water and is always at the top of the tank). As part of the conversion process, a crewman would have to go into the superstructure (obviously while the boat was on the surface!) and remove these blank flanges from the FBT vents. Once this was done, high pressure air valves for the blowing system were unlocked and made ready for use. The last step in the conversion process was flooding and blowing the tank several times to flush out any residual fuel. Once done, your FBT was now a MBT and was operated in exactly the same way.
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Old 02-05-09, 07:49 PM   #41
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Quote:
Originally Posted by Nisgeis
Also, after having a look at the pictures of the sections being constructed before assembly, it appears that the bulkheads are a single sheet welded at the ends of the pressure hull. Were the bulkheads made to fit inside the pressure hull, or were they the same diameter as the pressure hull. IE, when two sections were joined was it pressure hull - pressure hull, or was it pressure hull - bulkhead - pressure hull?

I also have a question about Normal Fuel Oil Tank number one. Was it completely sealed externally, with only valves to drain and fill from the inside in the forward topedo room? Even the fuel filling lines seem to be routed throught the torpedo room, so were there any hull openings at all through the pressure hull where Normal Fuel Oil Tank number one is?

Finally, how thick are the dividers between the ballast tanks? The drawings seem to indicate that they are fairly thick - were they?
Okay here is part three:

1. The bulkheads were built internal to the pressure hull sections and those sections were welded directly to each other. To do it the other way would have effectively doubled the number of critical welds. For obvious quality control reasons, this number was sought to be kept as low as possible.

2. NFO tanks were "sealed" from the sea. They did not have vents or flood ports like a FBT. However, as mentioned before these tanks were compensated to sea pressure in order to maintain proper ballast. Thus they did not have to be built heavy to resist full submergence pressure. Keep in mind though, that one side of these tanks was the pressure hull.

3. I do not have specific figures for the thickness of the divider between MBT's. Note that this "divider" was actually the ship's keel, so being a primary strength member for the boat it was pretty strong. There were limber holes cut in the keel so that the water could freely move from one side of the tank to the other, so in essence the tanks were not really divided.

Whew! That was a long series of questions. Time for a nap!
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Old 02-05-09, 08:27 PM   #42
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Default Boat variations and museums

Before you guys get too amazed at my seemingly inexhaustible supply of submarine minutia, I have to admit that I had to do quite a bit of research to answer the questions above effectively. I even conferred with a few of my fellow submarine veterans. One of these guys was Bill Parker, a docent at the USS Pampanito museum in San Francisco. In picking his brain, he reminded me of something that I already knew, but that justifies repeating. I quote Bill:

"After many yard periods including major overhauls, the one thing I learned above all else is that 2 boats could be built by the same yard at the same time to the same set of plans and still hit the water with different configurations.

Some differences were cosmetic, often resulting from the PCO and commissioning crew's preferences, (e.g. main deck gun forward or aft, where a locker was placed, etc.) and others were more significant because shortages of various equipment during the massive building program of WWII forced dockside changes in order to maintain a production schedule."

In considering this stuff it is important to understand that literally no two boats were exactly identical. Publications like The Fleet Type Submarine (NAVPERS 16160) and authors like John Alden, Norman Friedman, and Norman Polmar even though highly respected and very accurate were by necessity forced to generalize when writing about the boats. They simply could not account for every variation or modification. This will sometimes account for "mistakes" they made or for differences in "facts" from one author or publication to the next.

For those of you who have not already done so, I would highly encourage you to visit one of the many fleet boat museums around the country. It is a fascinating and rewarding experience that will leave you with a whole new appreciation for what the sub vets went through during their service to the country. For those of you who live in other countries, there are several submarines from other navies on display around the world, too. Stop and talk to the docents if you have a chance. They love to talk about their boats and are happy to educate people.

For a list of submarine and naval museums around the world, check out the Historic Naval Ships Association at http://www.hnsa.org/index.htm

Okay, now it is time for a nap!

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Old 02-06-09, 06:22 AM   #43
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Thanks very much for the info. I've done a lot of research, but some of it I have to assume certain things that may or may not be true. Sometimes it turns out that something I assumed was right and other times not. It's great to get the info from the someone who has knows, or knows someone that knows.

Do you know how thick the bulkheads were? OK, I'll lay off the questions now .

Thanks again.
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Old 02-07-09, 02:44 AM   #44
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Dave,

Is the watch system simulated in SH4 (4 hours on, 8 hours off), similar to what was practiced during WWII, and if not, how was it different?
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Old 02-07-09, 05:48 PM   #45
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Quote:
Originally Posted by Nisgeis
Do you know how thick the bulkheads were?
The internal bulkheads on the wartime boats that separated the different compartments were rated to the same strength as the pressure hull. As to the exact thickness I don't have the figure.

On some of the post-war submarines (like my Darter) the bulkheads were thinned out to save overall weight. This resulted in a crush depth for the bulkheads of about half what the outside pressure hull was. In other words, as long as the boat was dry internally, you were okay. But flood a compartment and the bulkhead would collapse long before the rest of the pressure hull would. It kind of invalidated the whole reason for having a watertight bulkhead to begin with, if you ask me.

Well, as we used to say, as long as the number of surfaces equaled the number of dives, you were good to go!!
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