Real submarine Technology Q&A -> Real submarine Technology Arguments, in session now!

good thing its constructive arguing, very interesting to read and look at all the pics you guys fish up (with no pun intended to the current argument)

Part of the answer as to where the external torpedo stowage was at can likely be found in this quote from Submarine Diary:

Sorry Neon, I can't see what you mean by the flat mushroomy thing. I can't make out the forward gun mount in that picture, could you circle the bit you are talking about?

They are both pictures of the aft?

Was Subic Bay a major yard? From reading patrol reports, the foundation ring was added at the same time the second gun was. I believe the mounts were installed ready to take a 5" gun, but only the foundation ring for the one that was needed was installed.

http://www.navsource.org/archives/08/08192a.htm

Ok thats the website where the pictures came from.

There are two pictures there in various states of construction.

One taken in April and one taken in July.

I thought they were bow and aft but you are correct they are both aft.

The captions wrongly identified them.



Photo 19 N 109862:

Squalus (SS-192), under construction on the building ways at the Portsmouth Navy Yard, Kittery, Maine, 7 April 1938. View looks aft, with forward torpedo tube supporting structure in the foreground.

It should say looks forward.

Cirlcle them:hmmm:

I will give it a try.

http://i680.photobucket.com/albums/v...rmount2222.jpg

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.