Gato Free Flood Holes

[carr]

Hi,

I'm new to this forum and it's wonderful.  So much information!

Pardon a seemingly basic question but were the Gato class free flood holes on the underside of the hull simple openings or did they have a cover screen of some sort?  I've seen some models that show simple openings and a couple of people have indicated that this was the case, however, I'm looking for something definitive like a photo, manual description, first hand knowledge, etc.  The reason for my doubt, aside from common sense suggesting that screens would be a good idea (you wouldn't want something lodged in a hole or rattling around inside a tank), is that modern subs have screens and the Gato anchor well, the only drainage area that I've seen clear photos for, has screen covers.

I've seen a construction photo of an upside down hull that has simple openings, however, since it's under construction, covers could easily and logically have been added at a later stage, so that doesn't prove anything one way or another.

Plans clearly show the outline and location of the various openings but give no clue as to the presence or absence of covers.  For instance, the valved openings appear essentially that same as the free flood holes on plans and yet they were "covered".

Can anyone offer definitive evidence one way or another?

Thanks,
Bob

[aptivaboy]

I think it depends upon time frame. During the war, they were generally simple circular or oval openings. There are some photos at navsource.org that show this. Look at the Manitowac-built boats, especially the first few boats like Peto. (http://navsource.org/archives/08/265/0826512.jpg) They tended to be built prefab upside down and are probably the ones you saw, so there are photos of their flood and drain holes. Screens could get clogged and slow diving speed, a very bad thing in the combat zone. They were added postwar, I believe, and may have been on the prewar boats until they went back for wartime refits. But, wartime boats generally had simple openings to speed diving time. The Eduard photoetch parts for the 1/72nd Gato has these screens, but it, and the model, were based upon the USS Cobia which was refitted postwar, and therefore doesn't represent a true World War Two appearance. She's close, but differs in the details. 

Wartime boats usually "rode the vents," with their upper flood vents closed and no drain vents on the hull underside, just those simple circular and oval holes. To submerge fast, you just popped the upper vents, releasing air in the ballast tanks, and submerged. There was really no need to have a complex lower opening because there weren't any actual vents there, at least for most boats. in doing some bare bones research and edumacated guesses, I'm pretty sure that most of the early Electric Boat Gatos were commissioned like this. Guardfish (SS-217) almost certainly was. That's why I believe the Manitowac boats were the same, as they were carbon copies of the Electric Boat design from SS-215's plans. As for Portsmouth boats, I have no idea.

Anyway, that's the way I understand it. There are people here far more knowledgeable than myself who certainly know more. Apologies if I've misused a term here or there.

Robert

[Rokket]

I'm in the same boat" Robert. I think you're right, but others will tidy. Some of the bottom ones were covered with flapper valves, called Kingston valves.

[aptivaboy]

Friedman indicates that the Kingstons were deleted very early in the Electric Boat Gato production run, perhaps even from the very beginning. He isn't very precise, however, even in his endnotes on this point, so I'm sort of assuming and educated guessing based upon what little information there is, and the Manitowac experience. Their contract with the Navy and Electric Boat stipulated that they were to build exact replicas of the EB planned Gatos, with no deviations whatsoever, at least in their first few boats until they got up to speed and experienced enough to go their own way. So, if Peto didn't have Kingstons, then I'm betting that every EB boat from SS-215 onwards didn't, either, since that would fit the strict contract terms. As for SS-212-214, who knows? At any rate, that's my assumption, admittedly based upon not very much.

I tend to wonder if the depth charge tests carried out on Tambor prewar had something to do with this, since they supposedly exposed many shortcomings with these boats' piping and ballast tank arrangements, fortunately in time for them to be corrected. The Tambors would have had the Kingstons, as built, but since they were removed or deleted from the early  boats under construction... Does anyone know anything else about this possibility?

Robert

[carr]

I very much appreciate the discussion and assistance.  I was only vaguely aware of the Kingston valves and never knew that they may have been part of the original design and been deleted. 

Here's some additional information - I have a copy of a BuShips docking plan for SS-276 which clearly shows and lists two types of hull bottom openings:  flood holes, and flood valves (their terms, not mine).  The plan also clearly shows that the flood valves are normally "covered" openings with the cover being part of the movable valve assembly.  Unfortunately, the plan gives no indication whether the flood holes are covered or not.  I assume that the covers, if present, would be passive, non-moving, perforated covers which act as a screen to keep large objects out (if I recall correctly, the anchor well cover specifies 2 inch holes for the perforations).

What is the difference in function between the flood holes and flood valves, aside from the fact that one is free flooding and the other is regulated?  In other words, why both?  For instance, the blueprint lists both Main Ballast Tank Flood Holes and Main Ballast Tank Flood Valves.  Seems redundant?

Are the Kingston valves what are referred to on the blueprint as flood valves or were they associated only with the flood holes?

Thanks very much for taking the time to help with this!

Regards,
Bob

[Mike K]

OK Guys, here goes. Flood holes were just that, Holes. No covers, valves or screens.
Flood valves are valves, two position (open or closed). The valve was a large oval or rectangular , slightly convex, steel plate, hindged on one side. The valve seat was a raised area around the inside of the hole.
Fuel-Ballast tank valves opened directly to sea, the Negative and Safety valves were located in a housing up, inside of the tanks.
The Flood Holes,or ports, were oval, rectangular or round openings, no gratings, no screens, no louvers.
If anyone needs drawings for these valves, drop me a email. I'll send what I've got.

Mike K.

[carr]

Mike,

Thanks!  That's clear and simple.  Just out of curiosity, what is your source (photo, book, first hand knowledge, etc.) for that info and what level of confidence do you have in it?

Thanks,
Bob

[wildspear]

Hey Mike,
Were the valve drawings in the group of drawings that you already set me? If not I'd like to get a set of drawings for the valve area.

[Mike K]

My source is the "Submarine Enlistedman's Qualification Manual" and BuShip drawings. I've scanned these, and can email them.
In addition Between 1958 and 1978 I served, and was qualified, aboard three Diesel Boats and two Nukes.

Wildspear, if I sent them to you, there'd be 4 drawings, 3 sets of Fuel Ballast flood valves and one generic flood valve drawings. I don't remember what I've sent you.

Mike K.

[carr]

My source is ...

Mike K.,

Outstanding.  Thanks for your help.  That settles the issue for me. 

As an aside, photos of modern boats show all openings "covered" with screens of one type or another.  Any idea approximately when that practice started and, more interestingly, why?

Thanks,
Bob

[Rokket]

Thanks Mike!

[Mike K]

On the diesel boats only intake openings would have gratings or screens, to keep garbage out. There was no need to protect discharge openings or flood ports or valves.
However, with the arrival of high speed subs (Nautilus, Albacore, etc) a new problem showed up. At high speeds you get resonance effects. Just like blowing across the top of an empty bottle. But water is much harsher. Nautilus' ballast tank were badly damaged by these effects.
That's why Albacore, and all nukes, have louvers on their flood ports and gratings/screens on any other openings.
Mike K.

[wildspear]

Mike,
Thats some good info. I geuss this old ground pounder can learn a few new things.

[carr]

Mike,

Now that is some truly fascinating information.  I never would have guessed and yet, once explained, it makes perfect sense.  Thanks very much for taking the time to educate me!

Regards,
Bob