Pre-WW1 Cruise Liners

[ArmchairSamurai]

What limited the production of the He-115? Given it's primarily naval nature, it was never considered a priority aircraft. The aircraft might not share engines, but they share aluminum as well as other resources.

The Ha-140 did not win the contest with the He-115...It lost!
The losing Ha-140

Wonder why it lost?? Might have something to do with the crushed float & starboard engine knocked loose from it's mounting. Can't say for certain, but the damage does not appear to be from "a lack of production."

Strange, I have seen multiple sites that suggest otherwise my friend. That is why I said as much... I do not doubt what you say, only I wonder then where the discrepancy came from given that is the case. Odd!

Let's see...You are putting out more commerce raiders, but want to do away with the auxiliary ships that were supporting them...Probably not a good idea. Converting the auxiliaries into seaplane carriers(with an air group of 20 or so floatplanes would negative their usefulness as resupply ships.

I am being too pragmatic, I admit. I only intend to limit the number of ships afloat, as you must yourself admit that these hypothetical commerce raider packs are quite big at this point, yes? That is my problem. That is to say unless, as Gardener suggested, they operate in many separate pairs, one capital ship to one seaplane tender (or even task groups) rather than a large flotilla.

Good overview of German Air torpedo development

https://weaponsandwarfare.com/2020/04/2 ... torpedoes/

Thank you, yet I have already seen that. I feel like there is a slight gap in information regarding German torpedoes prior to 1938 though.

I started reading through this:

https://digitalcommons.georgiasouthern. ... ontext=etd

It's a good read so far... *shrugs*

[Peter89]

Alright, so it has been determined that given the OTL constraints, modifying merchantmen into seaplane tenders would be a more realistic option for German "carrier" action and they would likely serve as commerce raiders along with other OTL ships in that same role. However, the next problem is with which seaplanes will these tenders operate? Worse, how to overcome the torpedo problem prior to the French stock being captured?

It couldn't be overcome. German aerial torpedo development (both the technology and the doctrine) is a shining example of how the Germans mismanaged their resources and opportunities. Even in early 1940, when the waters of the North Sea and around Scandinavia were teeming with perfect targets, only a very few torpedo attacks were authorized. Information did not went smoothly from the KM to the LW, etc.

My first question: if the He-115 is in low numbers up to 1940, what is stopping Heinkel from producing more? To my knowledge, the only planes under Heinkel up until late 1940 are the He-111, He-115, and He-59, with none of them using the same engine; but that is not to say Heinkel is not having to share engines with other planes from other manufacturers, because that could very well be likely. Could it be that OTL these planes would typically operate from a coastline base, and prior to the fall of France / Norway, these forward operating bases were not available, therefore making the plane non-essential? It cannot be the lack of manufacturing capacity, because that is why Blohm & Voss declined to produce the Ha-140, even though it won the contest that the Heinkel was reluctantly awarded.

It is a very complex question, because the Germans produced aircrafts more and more effectively: more fast, with less man hours, from less materials. The labour organization and the learning curve plays a key role here, but in any case: there weren't much more potential seaplane carriers around, and if there were, there weren't enough torpedoes around: thus, we are talking about a dozen or less ships here.

Also Takao is right about the BV Ha 140.

My second question: could the Fiesler Fi-167, if converted to a floatplane, be sufficient in the role required for these tenders? Said ship was to be the designated torpedo / reconnaissance plane of the Graf Zeppelin when it was being constructed, only losing out to the Ju-87 in that role once the carrier's construction was resumed in 1942. I make this suggestion because, in theory, the Fi-167 would be the counterpart to the Fairey Swordfish, which was not replaced by the Albacore until March of 1940. Otherwise, would the Ju-87 be selected anyway, much like in the OTL, only instead of arrestor cables, it has floats? Can Junkers handle the increased production numbers that this would bring on?

I see that is highly unlikely. Such a conversion could be problematic from a technological viewpoint and could take a lot of time. Besides, why would the Germans do that when they had floatplanes? What they did was to modify the torpedoes so they could be launched from He 115.

My third question: with the introduction of such ships into the commerce raider foray, would the earlier introduction of CAM ships be a realistic British response? If that were the case, then that opens up the vulnerability of the tender's torpedo-bombers to fighter attack, though only one at a time per ship, and depending on how many CAMs are encountered per convoy; therefore each tender might need a least one fighter escort for their bombers if only to fight off a possible CAM response. The Arado Ar-96 would be suitable to fight Skua or Swordfish as pointed out by Gardener, but how would they fair against the so-called "Hurricat"?

CAM ships came online later, besides, their role was exaggerated, even against the Condors. The opening in the British convoy defenses were the lack of low-altitude AA guns, which were stripped from the ships and sent to Britain's defense. As soon as the British had enough Oerlikons and other low altitude AA guns for their merchantmen, the vulnerable, slow, big Condors were either shot down or damaged, or simply chased to a high altitude bombing, which ruined their accuracy and made their effect marginal. (Not to mention the Germans didn't have a proper bomb sight for the new mission at their disposal at the time.) Most likely the seaplane raiders could find an opening, too. Thus: launching a hundred of torpedoes and scoring a few dozen hits is what we are talking about. But these opportunities would cease as the AA guns would get back to the ships.

Also, the introduction of the CAM ships, CVEs, etc. would be a net gain for the seaplane raiders: these things costed a lot, a disproportionate response.

My fourth question: would the pairing of such tenders with surface ships like Bismarck, Prinz Eugen, Tirpitz, etc., necessitate the additional use of auxiliary ships for refueling / repair / rearming purposes, or could those too be converted to carry planes, thereby eliminating the need for extra ships? Would they be paired at all, perhaps operating among similar ships, but never with big targets like capital ships? Otherwise, the commerce raider packs I am envisioning are starting to balloon into convoys, and with more ships, comes a larger target for enemy reconnaissance. This comes more into play with what EwenS mentioned in his post, as these ships played off being less of a target, but in the vast openness of the North Atlantic or even the Indian Ocean, they would do little alone, compared to the wolfpacks operated by their submarine counterparts, without additional support. Am I wrong to think this?

Well, the pairing would not work. Bismarck et alors moved with 28-32 knots, these ships could maybe move with half of that speed. No wonder why Graf Zeppelin was designed to move with over 30 knots, too.

Also the auxiliary cruisers used disguise and not power or speed. Forays into the Indian Ocean was only possible as long as IEA or Madagascar could be used as bases of operation. But the Italians eliminated that option quite soon, so yeah.

My fifth question: (this goes along with what my last question touched on) would such convoys be better suited for Indian Ocean operations as compared to the North Atlantic? Leave the open Atlantic Ocean to the submarines, and send the tenders to waters less in the iron grip of the RN, as the IJN's influence is nearby. This might make sense tactically, as the Suez Canal kept the flow of armies, weapons, and supplies to the Mediterranean and if the Indian Ocean becomes hotly contested, that would require the RN to pull more ships away from elsewhere to keep the shipping lanes open, which in theory, would help the U-boats in the Atlantic.

The British had squadrons scattered all around the globe, perfectly capable of dealing with any sort of such threats. What Raeder envisioned (in my opinion, correctly) was a large enough commerce raiding party that could draw significant British units away from the home isles, something that simply didn't happen until the Bismarck sunk the Hood.
There was no way to contest the South Atlantic or the Indian Ocean. What could be done was to wreak havoc and disrupt operations.

My sixth question: what kept German torpedo development? The only serious effort I know of within Germany for the industrialized testing of torpedoes was the Torpedowaffenplatz Hexengrund, and it was not operational until 1942. Was this merely an interbranch squabble, where the Kriegsmarine and Luftwaffe would not work together? I see the Italians sold Germany a torpedo, and the latter effectively copied it from my understanding; why was this not done sooner? It really seems like the naval air arm was significantly neglected prior to WW2. I suppose that makes sense given the wider tactics used in the early days focused more on land-based aircraft as opposed to sea-based, but it's still notable enough to mention.
I am sure I missed a lot of things I could be proposing.

It's a long story, but in summary: Germany did not develop a torpedo of its own before the war, they used obsolete Norwegian and Italian designs. The KM did not share information with the LW, and the LW was convinced that they can sink ships with bombs; even though a contemporary LW general commented that how many high caliber shells did hit the Derfflinger at Jütland and it still didn't sink. Germans scored their first hit & sink with an aerial torpedo during the SCW, but they simply didn't press the issue, although the report of that mission was clear and it survived to this very day. I found an English translation of a part of it.

‘The AS/88 with three He 60s was first set up as a sea
reconnaissance flight at the beginning of the Spanish Civil
War in the summer of 19306.The aircraft were single-engined
floatplanes and carried out sea reconnaissance for German
ships stationed in the western Mediterranean at that time.A
strengthened Staffel was eventually formed from that and
when I took over, the unit had 12 He 59s, two He 60s for
reconnaissance and one Ju 52 transport aircraft. My task
was [primarily] fighting enemy supply ships going to the
east Spanish harbours from the French border to Almeria.
Doing this though, I was not allowed to attack ships on the
sea; even the English protested at attacks within the threemile
zone, so essentially I was instructed to attack in the
harbours, which were however strongly protected by flak.
Further, I was to attack military supply establishments, oil
tanks etc for example, and lines of communication within a
coastal strip about 30 km deep. With the restrictions of
attacks at sea, only missions with bombs were applied.I had
six F5 airborne torpedoes and also a torpedo mate at my
disposal for regulating them. Before my time however, no
airborne torpedo had been fired by the AS/88.
‘One night, in order to test the usefulness of the torpedo,
I took off in an He 59 which was loaded with an F5
torpedo and, starting at the French border and going south
along the Spanish Mediterranean coast, tried to find a
shipping target as near to land as possible. Just outside
Valencia harbour, I saw by the light of a weak crescent
moon, a medium-sized steamer coming in about 1,000
metres in front of the mole. I knew the torpedo’s
weaknesses concerning its depth and sensitivity on impact
with the water. The water’s depth was only 16 metres. I
therefore throttled the speed back to about 120 km per
hour and released the torpedo from a height of only 5
metres. I turned out to sea and saw the course of the
torpedo.I had estimated the steamer’s speed at 5 to 7 knots.
According to the stopwatch, the torpedo had travelled
1,800 metres when I saw a high water column rise next to
the steamer’s funnel. The steamer had not entered the
harbour but was alongside the mole. It was the English
steamer Thorpeness (4,700 GRT). This was the first and
remained the last successful torpedo attack before the
Second World War. As no one had noticed my arrival and
departure from Valencia, Franco informed the English that
the ship had struck a mine’

The Germans had a lot of promising projects in their development pipeline, but they made a series of atrocious mistakes with the management of them, and pressed insane projects like the He 177 as hard as they could.

[Takao]

Strange, I have seen multiple sites that suggest otherwise my friend. That is why I said as much... I do not doubt what you say, only I wonder then where the discrepancy came from given that is the case. Odd!

Yes. But, if you trace the quote, it is from the Chief Designer of the Ha-140. Of course, he would not design an inferior aircraft.
Multiple sites do not mention the damage to the Ha-140 during the "fly off" with the 115. Most sites do not mention the Far longer takeoff run of the Ha-140 vs the 115. Nor, do they mention the greatly improved handling capability He-115 over the original prototype(1937 prototype vs 1938 "flyoff" winner).

You see, as originally designed, the 115 prototype was a poor aircraft. This is highlighted in the scathing flight report of the 115 prototypes first trial flights. While similar reports for the 140 show little amiss. It appears that these 1937 initial flight reports are considered the "contest" the 140 "won". However, they are only initial fight reports, not the 1938 fly off between the 2 aircraft.

Any way, Heinkel went back and reworked the control surfaces and added control tabs, which greatly improved the 115's handling capabilities resulting in glowing flight reports later on, well before the aforementioned flyoff.

I am being too pragmatic, I admit. I only intend to limit the number of ships afloat, as you must yourself admit that these hypothetical commerce raider packs are quite big at this point, yes? That is my problem. That is to say unless, as Gardener suggested, they operate in many separate pairs, one capital ship to one seaplane tender (or even task groups) rather than a large flotilla.

Not that I see. You have the raider and the seaplane carrier operating in close proximity, while the support ships were usually prepositioned in certain out of the way areas. The raider would rendezvous with the support ships when needed, but generally did not operate with them for an extended period of time. The exception, I believe was the battlecruisers Scharhorst & Gneisenau.