This is a big post, hope it all goes right!
Firstly, the Japanese are going to cotton on, secondly, submarines make appalling seaplane tenders, getting stuff out through the conning tower will be a difficult and laborious process, which will increase the risk of the Japanese catching the flight landed. As well, seaplanes aren't real good as bombers, that hull can't be converted into a conventional bay, so the munitions will have to be dropped over the side, limiting their size.
cotton on = ???
If I was planning to attempt to use a submarine as a seaplane tender, the first thing I would do is design it to suit that purpose, and a conning tower is going to kinda be in the way. If I had a conning tower at all, then I would have to build a sloping back deck so the seaplane could be catapulted off {if I were going to go with a catapult assisted take off}. If I am just going to have them on a "service" deck type of arrangement, where the seaplane motors astride the back of the sub for servicing, then the conning tower typical of a regular {unmodified} submarine design would not be in the way, but I would still need something like a hanger that could be made dry when on the surface, and this is where the consumabales would be transfered. In other words, stuff would be moved out of the pressure hull horizontally into the 'hangar' area, and then wheeled up under the seaplane. No loading unloading woult take place through the conning tower. Only a specalized submarine would be used for this purpose.
Yep, since a seaplane/flying boat has to have a large chuck of its airframe optimised to operate on water that part is by default very crappy aerodynamically, making the rest of the plane work harder to fly well.
These are valid points. Now I need to be able to draw a picture of how I want to engineer around that as best as can be. If no one can tell me where to get a free drafting program, then brace yourselves for the worlds worst free hand drawing ever to disgrace the internet, lol.
The stern elevator is an interesting idea, and it could potentially be larger than the deck-edge lifts. Whether that's a significant advantage or not, I don't know, but it could handle larger or more aircraft at a time, so there's that. The problem I see is that it's positioned right where you want aircraft to be landing, and reinforcing it to take those sorts of impacts is going to be an issue (let's not even talk about arrestor wires). I'm sure you could train naval aviators to touch down forward of it, but then you're cutting into the amount of deck space they have available to take off in if they miss the wires. I'm also a bit alarmed about the idea of aircraft, damaged or not, undershooting the wires and slamming into the biggest lift on the ship - somehow that doesn't seem like a very good idea.
Still, no naval architect I. Anyone who knows more care to comment?
The stern elevator would never be used for landings. It would always be in either the hanger deck level position, or lower while landing ops were underway. Someone else mentioned loading aircraft on this elevator at this time {during landing ops}, that also would be a no-go.
A sternelevator might have benefits, but also some unwanted countereffects. Structurally, it makes sense in shipstructure and hulldesign, but it comes at a price of being a hazzard for flightdeck operations, especially with landing aircraft. Aicraft being moved up and down on such an elevator are simply in the way when landing aircraft at the same time.
Which is why you don't try to use this elevator while landing ops are underway.
I'm missing something here. Is this ship an aircraft carrier or a seaplane tender? Both have very different requirements, and attempting to do both means that they do neither well. Building this ship for the Dolittle raid seems pointless.
And if I was saying to make this carrier just for that purpose, then you would be absoutely correct. OTL USS Hornet didn't have any modifications in order to carry out the doolittle raid, so why would I need these modifications? Because I want to have an ATL where seaplane technologies are not just shoved aside as historically, but rather {for whatever crazy reason} every effort is made to integrate flying boats, seaplanes, and 'float' planes into a seamless whole. I want to explore the wonders of "What If..." for many different possibilities and aircraft development paths. The roads not taken historically, but roads that might have been.
That kinda thing.
Is the stern elevator supposed to dip into the water and pick up flying boats?
It is.
A crane can accomplish that with far less complexity.
Really? I understood that the ships that were relying upon cranes tp recover their seaplanes had to basically stop dead in the water to make that kind of thing work. If you want to do that, then any float plane equipped vessal can to that. But, if you want to recover while underway, how can the stern elevator fail to be the simpler and better way to go?
If the seaplane is supposed to fit on the hangar deck, which aircraft did you have in mind, or is it a custom build?
It would indeed depend on what actual planes were involved. Could a PBY be lifted to the flight deck? Probably. Would it fit into the hangar deck? Probably not, unless your going to alter either the plane or the hangar deck {or both}. Could a PBY take off from a carrier? IDK, but the B-25's {or was it B-26's} of the Doolittle raid did historically, so maybe this is not undoable. Now, if the USN has developed aircraft {in accordance with the above reply} that are equally capable of operating from the carriers, or from seaplane tenders, then the carriers could shuttle the seaplanes to within range of the waiting submarine tender flotilla, where they refuel and head out for the target. OTOH, perhaps the actual doctrine would be to hit the target, and then make rondieve. Or perhaps, some would hit the target, first, others would remain overhead and strike when the Japanese attempt to take off, and others woul then come in after they had refueled. I am not really at the strategy and doctrine level yet, this is more of a 'get the initial concept out there' kinda thing, and we can toss this back and forth till we come up with something not too crazy, but off beat enough to make it interesting and worth the time it takes to read it.
Well, since the A6M had a land based combat radius that was realistically more limited by pilot endurance than fuel you will need some damned long legs on even the float planes (and God protect the sub crews who would have to surface, in daylight and within range of land based enemy air, to refuel these floatplanes).
I cannot argue that, but I feel the need to point out, any improvment in the range the USN carriers can strike from, is a good thing. Does it matter that the Zero's are still going to be able to have a chance {however small} to be able to escort a counter attack back at the USN carriers, attacking from much farther away than they otherwise could have made a strike with their regular airwings? I'm not convinced. And even if a counter attack takes place: Is it before or after the seaplanes are off? If the carriers worked in pairs, as in the OTL Doolittle raid, then one carrier has it's regular airgroup stowed in the hanger deck, while the other is providing CAP.
Basically, Does this potentially allow the USN carriers to have a chance to hit and run, from a greater distance? Yes. Does this make them immune to coming within range of Japanes land based air? No. Does is drastically reduce the time they have to spend within range of the Japanese land based air? Yes. Does it also make the Japanese have to search further afield, and cover a much greater total search area? Yes.
Is it perfect? No.
Is it doable? Who knows.
Is it interesting, and thought provoking? Lets find out.
These floatplanes will be attacking defended bases, with either Zeros or Oscars (or even the A5M Claude) with no fighter protection and with questionable maneuverability and pathetic speed (float planes travel at perfect speed, assuming you are looking for a target sleeve). Be far easier to just toss every third pilot off the edge of the deck in a straitjacket, be cheaper.
Actually, I have to apologise, if I gave the impression that these airstrikes would be carried out with "off the shelf" seaplanes & floatplanes of the OTL US armed forces. The PBY's would make good for picking up downed aircrews and reducing US attrittion losses, but I wouldn't want them going into battle zones unescorted.
The bolded assumptions are my fault, as I have not even come close to explaining what I am looking for in the actual ATL seaplane/floatplane aircraft I have in mind.
I
really need a drafting tool...
Jack of all trade designs are almost always failures, especially in ship design. You have so little budget for reserve buoyancy, strict limits on hull volume, and, until the nuclear reactor, serious limits on both bunkerage and engine power that any attempt to do more than one thing is almost foreordained to fail.
Well, I know your telling the truth on this point, but just what all would really be needed to include an additional elevator?
If you want to improve the
Yorktown class, work on the underwater protection scheme. You could drop bombs on them all day and the class would give you the finger, but if a torpedo ran
near one, it was curtains (
Yorktown, Hornet & Wasp (a "CV 5 light" design), all died from torpedo hits.
Enterprise, the only
Yorktown class to survive the war, was able to shake off multiple bombings, and two separate Kamikaze strikes with aplomb, thankfully she was never torpedoed (or we would have had to find another cool name for NCC-1701

).
I remember reading about WWII on my own time as a child, and wondering just how often our carriers were getting hit by Japanes submarine's torpedoes. I was like, WTF?
Not sure I want to try to improve the Yorktown class's underwater protection scheme in addition to all the other stuff I want to change, but then again, maybe my changes force the design to have a wider hull to offset the top heavy additions, and this makes for a fortunate accident of conicdentally improving the torpedo protection?
The way to recover a seaplane in dodgy weather is to make a turn to put the crane on the lee side, so to create a smoother area of water. The wake of a 30 knot warship like a carrier sucks as a place to recover seaplanes, they need slack water that a carrier stern doesn't provide. Sorry, I know you want it to happen.
Heh heh, I wonder what one would do, in the way of altering the stern of a carrier, so that we can alter and tailor the ships wake to expediate the recovery of seaplanes as outlined? Hmmmm. Interesting engineering task detected.
These two points can't be refuted.
In WWII, the Japanese First Air Fleet had 10 carriers, and that was the largest aircraft carrier fleet on the planet. My point being, a single aircraft carrier is of huge importance. The Doolittle raid was entirely a propaganda victory, it achieved no quantitative strategic goals. Going into WWII, the US had 4 aircraft carriers.
You are suggesting that it would have been advantageous to increase America's carrier fleet by 25% for the sake of propaganda.
Uh, no. I am interested in an ATL where somebody in the USA gets the idea to try to make the most of every aspect of the aviation industries efforts to make viable warplanes, even out of seaplanes, floatplanes, and other amphibious craft. I also want to explore the concept of a purpose built submarine 'seaplane tender', as this offers advantages of the surface ship alternative. All that, and the carrier with a seaplane elevator too!
Furthermore, when comparing a stern elevator to a crane, you spend far more than you gain. An elevator would operate consistently regardless of weather or speed, but it would be so much more expensive in terms of both resources and development that it would be smarter to accept the tactical disadvantages to reap the logistical reward.
I cannot see that, myself. Having to either come to a dead stop, or just barely making steerage, while in a combat situation? Nope, let me just spend a bit more coin, and be able to recover my seaplanes while underway, and damn the costs.
