I am not entirely sure of their exact capabilities, but Subic Bay and/or Cavite would have most likely been able to conduct major overhauls and do the rework that I described. Obviously, these yards were lost at the beginning of the war, leaving only Pearl Harbor west of the mainland. Strangely, Pearl generally did not handle overhauls and left the major work to the west coast yards in Bremerton (in Washington state), Mare Island, and Hunters Point (both in San Francisco), with submarines going mostly to Mare Island.

The circled item in the pic above is the after torpedo room access hatch, not the aft gun mount. The angled torpedo loading hatch would be immediately forward of this hatch and is obscured in this photo. The access hatch was left out of the diagram that Neon posted above, leading to some of the confusion.

The earlier photo where the pressure hull is incomplete was taken from very nearly the same spot. What you are seeing here is the aft end of MBT #4 and the inside of the after torpedo room. Just below where the worker is standing and below the wood plank you can see Fr 176 written on the tank wall in chalk. This means frame 176 and this frame is in the far aft end of the boat. The difference in the two photos is that in the 2nd photo the aft torpedo tubes and the WRT tank have been added and the pressure hull completed.

The hatch trunk itself is 26 inches in diameter all the way to the top. The "mushroomed" portion at the top is metal flashing attached to the trunk so that the teak decking can be attached once installed.

In the earlier photo you can see that none of the aft superstructure has been installed. Looking forward from the hatch you can see the framing ribs of the top of the pressure hull, with the main ballast and fuel tanks already completed on the port and starboard sides. The small horizontal cylinder offset just to port is an engine muffler and just forward of that is a vertical cylinder that is the engine room access hatch. Beyond that it gets harder to make out what the structures are, but the large one on the center line is probably the support structure for the conning tower. The aft gun mount would be just aft of the conning tower and is completely obscured in this photo.

The later photo shows the aft superstructure installed right up to the aft torpedo loading hatch. There is a large section yet to be installed, the portion around the hatches and aft all the way to the tip of the stern, just below the bottom edge of the photo. Just aft of the hatch you can see four attach points (two per side) were the superstructure supports will be welded to. Going back much further forward, you can see the horizontal cylinder of the conning tower installed right on the center line. The fairwater and periscope shears have not yet been installed.

That's the after torpedo room's escape hatch. It's flared out like that so a rescue bell can get a pressure seal.

Interesting, I didn't know the earlier boats had more frames than the later boats. Was that to do with increased pressure hull strength by switching to higher strength steel?

Speaking as a spectator way back in the cheap seats, I really enjoy this discussion. No personal attacks, just a passionate academic argument. :salute:

I don't have a definite answer for you, but I believe it had to do with weight. Squalus was one of the Sargo class boats that ended up being badly overweight when completed. Portsmouth Navy Yard had to go back and cut away portions of the superstructure framing (amongst other changes) to bring the boat into specs before the Navy would accept it. This experience was an unpleasant surprise for Portsmouth and from that point on they became real weight watchers (Electric Boat and the other builders followed suit). The designers took a very careful look at the design and probably decided that they could safely eliminate some framing without compromising the strength. These weight saving measures were a good thing as the boats built up such a weight margin that during the war when new gear was added it could be done so with out problems.

There is too much hull behind the pedestel to be the tropredo room hatch and it is too tall.

Picture of the Seadragon with aft torpedo hatch and torpedo loading hatches open.

http://i680.photobucket.com/albums/v...ohatchopen.jpg

The torpedo room chamber has a pronounced curve to it. The hull continues almost straight well past the pedestal. Look at the picture of the diagram and you can see the angle decrease sharply before where the aft torpedo hatch is.

If you look closely at the photo of the Seadragon, at the after most hatch, you can see two features of the torpedo room escape hatch. One is the large metal flange that sticks out, to facilitate docking with a McCann rescue bell and the other is the lugs used to attach the cables that the rescue bell would use to pull itself down. You can see both of these features in the previous photo showing the almost complete sub.

Unlike later designs, the early designs have the deck superstructure blended in to the hull, so it does make it look like the deck is flush with the hull, but it isn't. If you follow the line of the ballast tanks and the deck superstructure down, you can see that the line where the deck superstructure meets the ballast tanks is clearly defined and stops just forward of the torpedo tubes. Also, if you look aft of the capstan, you can see that there is a taper down instead of the harder lines of the later boats.

Ok then why is there not a steep rise in the bottom of the hull in the April picture? The one with fr 176 on it?

Diagram of the after section of Salmon/Sargo:http://i680.photobucket.com/albums/v...agram22222.jpg


The green arrow shows the hull rise and the circle covers the torpedo room hatches. The rise in the hull starts in the aft engine room.

Take a look at the july picture and imagine the propeller shafts clearing the bottom of the hull at the pedestal. Wouldnt those be some very long prop shafts?

Also. Just what does FR 176 mean?

Davey said that FR 176 is Frame 176. I thought it might have meant that, but I initially discounted that, as I didn't know the early boats had so many frames!

The hull rise at the green arrow is there in the April pic. If you look at the relative distance from top of the hull, to the deck in the centre to the distance to the bottom of the hull, then the lower section is about 2/3rds the height of the upper section. The upper section is the after torpedo room and the lower section is MBT #4. Looking at the diagrams, this fits nicely with what the diagrams show, that the section at end of MBT #4 is about 2/3rds of the height of the torpedo room.

The way to be 100% sure is to get hold of a book of general plans, that lists the frames numbers, then it will be very easy to see where that part is. Unfortunately, I only know of a Balao class booklet online and no Sargo.

The props are fairly long, as they have to go all the way to the machinery room, which is about 40 feet I think. On one of the earlier diagrams you posted, it shows the prop shafts externally and there's a measuring box showing what 20 feet looks like. The prop shafts are easily longer than the 20 foot sample box.

Just want to say,this is a great thread guys! Lots of real good stuff,keep it comming!:salute:

I arrive a little late for the periscope colour filters question that Arclight posed some time ago, but if it's still of some help, I'd like to point out that german WW2 submarines had two exchangable colour filters in the oculars: Deep neutral and orange. Orange was used to allow looking at a target against sunset/sunrise, as the orange blocked the intense orange sun rays, while the deep neutral (Looking like fog, soft grey) was used specifically to eliminate the disturbing small light reflexes in the peak of the waves in bright sunny days. :up:


As for moving torpedoes from the stern to the bow torpedo room, I have no idea if someone actually did it, but if I had to (And I find it highly impractical, since it's easier caluclating a solution for a stern shot than taking the pains of moving the torpedoes around:haha:) I would do somethings more simple:

1.- Eject the torpedo from the stern torpedo tube into the water, ensuring it is set to float
2.- Tow it along the hull forward and
3.- Submerge the boat until the bow torpedo tube aligns with water level
4.- Push it backwards in

No really, I know this won't work in real life, but it feels cool to have found a solution :har:

As theories go, it's a nice one. I'm no expert, but I think I read that only the practice torpedoes float and that's because they have a cannister in them that expels the water in the dummy warhead after the fuel is spent and the run complete and they bob to the surface. Live torpedoes float in the water just like bricks don't (sorry Douglas).

Submarine Museums
 

I would like to take this opportunity to once again strongly encourage everyone who plays and enjoys SHIV to visit one of the many submarine museums throughout the country. There is nothing like being in the boat to provide you with the perspective necessary to truly understand how things worked and what the submarine sailors went through on patrol. A lot of this left field stuff we talk about in this thread will make sense if you can see it in person and put your hands on it.

Some of the boats had post war Guppy mods and some (like the Albacore, Blueback, and Nautilus) are "modern" post war designs. But all of them will provide the basics necessary for understanding the fine points of submarine design and history. Some of the boats are in mint condition, and some are showing the ravages of time. All of them desperately need your support in order to keep operating.

The following link: www.hnsa.org, will direct you to the Historic Naval Ships Association website. There you will find a comprehensive list of all the boats on display. Obviously most of them are on the coasts, but for those who live inland, don't despair! There are boats in unusual places like Michigan, Arkansas, Oklahoma, Pennsylvania, Wisconsin, and upstate New York! For those of you in other countries, several submarines from other navies are on display around the world and these boats are listed as well.

All of the boats are worth visiting (I myself have been to six of them), but for the true experience I recommend the USS Cod (SS-224), located in Cleveland, Ohio. She is the only boat that has not been altered for ease of access. You have to go up and down the vertical ladders and through the trunks just like the real crew did. She is in great shape and even has a fully functional TDC.

If you live near one of the boats, they are always looking for volunteers to help with maintenance and cleaning. They would be happy to get your help.

Please visit one of the boats. It is a great time and you won't regret it!

being from the SF Bay Area originally,I have visited USS Pampanito SS-383 on several occasions. Very cool,and if you are in the area,you might want to take a hop over to the former NAS Alameda and vist USS Hornet CV-12.:up:

Actually, Hitman's procedure, even though totally and utterly impractical (sorry!), is technically doable. It just needs a little massaging. Torpedoes are designed to be neutrally buoyant, so you don't have to worry to much about them sinking, just very carefull. So, a modified procedure would look something like this:

1. Flood the tube and open the outer door. Attach a line to the nose of the weapon and pull it out of the tube. If you eject it it will go a long way, even if the engine doesn't start, then you would have to run it down. Pulling it out of the tube at sea will be a problem, though. Even though neutrally buoyant, it still has about 2000 pounds of mass, making it hard to move.

2. Tow it along the hull forward. Pretty good, but you got to be careful not to bang it around.

3. Submerge the boat until the bow torpedo tube aligns with water level. Oops. Remember, the forward tubes on a fleet boat are underwater at normal trim. Therefore, you would have to raise the bow to get the tube to surface level. On the surface all main ballast tanks are already dry, so it is hard to raise the bow. You would have to flood down the stern and pump dry the forward trim tank, and then probably move a lotta stuff aft to trim up the bow enough. It would be far easier to push the fish downward (remember, the fish is neutrally buoyant) until it lined up with the tube, flood down the tube, open the outer door, then...

4. Push it backwards in. Perfect.

In 1985 on the Darter, we were in Pearl Harbor and had to unload some Mk 37 warshots to storage. The way our after torpedo room was arranged, it was a lot easier to just float them out of the tubes and hoist them to the pier with a crane. So with a couple of divers in the water we did just that. It took about a quarter of the time. We were alongside the pier at the submarine base, though and not at sea.

I have to say one more time that while the procedure described above is completely impractical and unnecessary, it is technically feasible. :timeout:

You mean it actually could work on that variant you explained? :o LOL not bad for someone who studied humanities and not sciences :rock:- I'm a jurist, but Gene McKinney and a few more also were and didn't fare bad at all :D

Yes, that I knew, hence the idea :up:

Ahhhh my bad, in the U-Boats a pair of the tubes are above the water
, so I didn't think in the US boats it wouldn't. Well come to think of it, actually in the boats equipped with external firing tubes they certainly are

:hmmm: I have a nice photo of USS Permit showing them just below the deck level, and also look at my signature :DL, so in those it would work out I suppose. Or in the other boats you could put the torpedo on the deck and surface the boat having it aligned with the hatch for torpedo loading :O:

Cheers :yeah: As I already said, a stern shot is always the best option.

I also wanted to add that it is a HONOUR and a PLEASURE to be able to talk with submarine and surface ship veterans like you or Steve and be able to learn so much and enjoy your comments. I love subsim.com :salute:

I am REALLY enjoying this thread! It's chock full of great information and history. I am a career US Army Infantryman, so not much real world experience with ships and such, other than some Zodiac small boat ops:03:
That said, I keep learning more and more from this thread with every post. Thanks guys, and keep it coming.:salute:

Hmmm, I'm not convinced the larger torpedoes floated. I think they are a couple of hundred pound heavier than the water they displace according to my highly accurate napkin and pencil calculations :DL.

OK, so the Mk. 37 is a 19" swim out torpedo, like the cutie? There'd be no suction holding it in the tube, like there would be for a 21" torpedo. Would it still be possible with a 21" torpedo? Would you have to have the flood or vent valves open to let air or water in behind the torpedo, or you'd have a bit of a job on your hands?

Sigh...Folks, the operative word here is feasible... I knew I was going to get in trouble with that post! :har:

The inside diameter of a Mk 32 torpedo tube on a fleet boat is actually 21.125", which is slightly larger than the diameter of a Mk 14 torpedo. Spread out along the bottom of the tube are four rollers that the fish actually rests on. With the tube vented to sea pressure, any suction effect would be minimized.

However, with almost 2000 pounds of mass and using nothing but Armstrong Engineering to get it out of the tube, just getting it moving and then controlling it once you are moving is a tall order.

Once again guys...feasible, not practical or realistic. :D