BB conversion What-IF

[guctony]

If imperial navy decided to convert some of their BBs to CVs. What would be their probable operational plane count.
Also would kongo class be a more probable conversion candidate or they would not give a way their fast capitals.
Does 360 day would be enough for a conversion delay

[Puhis]

ORIGINAL: guctony

Does 360 day would be enough for a conversion delay

I doubt it. Conversions of Agaki and Kaga took years in late 1920s. Even later modernisations of those two took over a year.

Chitose class conversions from seaplane tender to light aircraft carrier took about 10 months, and I'll bet those coversions were rather easy...

[herwin]

ORIGINAL: Puhis

ORIGINAL: guctony

Does 360 day would be enough for a conversion delay

I doubt it. Conversions of Agaki and Kaga took years in late 1920s. Even later modernisations of those two took over a year.

Chitose class conversions from seaplane tender to light aircraft carrier took about 10 months, and I'll bet those coversions were rather easy...

They were designed for the conversions. Look at conversion times for the RN carriers for an estimate. The Cleveland class conversions were done during construction, so they're not really representative.

[DuckofTindalos]

It's not even close to being enough. And if the Kongos were converted, where would the new carriers get heavy escorts from?

[herwin]

ORIGINAL: Terminus

It's not even close to being enough. And if the Kongos were converted, where would the new carriers get heavy escorts from?

Heavy cruisers, like the American carriers. Still, those countries that had heavy escorts valued them. The RN seriously considered keeping the Renown after the war because it was such a good carrier escort.

[JWE]

ORIGINAL: guctony
If imperial navy decided to convert some of their BBs to CVs. What would be their probable operational plane count.
Also would kongo class be a more probable conversion candidate or they would not give a way their fast capitals.
Does 360 day would be enough for a conversion delay

Frankly, Tony, I do not think this is either desirable or wise. Terminus is quite correct – not even close. Shinano was converted when it was still a general hull, with no significant topside facilities. It still took more than 2 years to complete the conversion, even with a partially completed vessel. To reconfigure a BB to a CV would take more time than that required to build a new one from scratch. Heck, it took 7 months just to re-do Ise to a BBCx so she could launch (but not recover) a total of 21 planes, most of them floats.

All that “Capital” conversions do is put your capital ships in the shipyard for 2 years or more, after which they aren’t as capable as a purpose built ship, and your gun power has just gone away.

Nope, bad idea. If your mod’s world view supports the time, materials, resources to convert a BB to a CV, it will certainly support building a CV from scratch. That would be both cheaper, and less time consuming.

[guctony]

ORIGINAL: JWE

ORIGINAL: guctony
If imperial navy decided to convert some of their BBs to CVs. What would be their probable operational plane count.
Also would kongo class be a more probable conversion candidate or they would not give a way their fast capitals.
Does 360 day would be enough for a conversion delay

Frankly, Tony, I do not think this is either desirable or wise. Terminus is quite correct – not even close. Shinano was converted when it was still a general hull, with no significant topside facilities. It still took more than 2 years to complete the conversion, even with a partially completed vessel. To reconfigure a BB to a CV would take more time than that required to build a new one from scratch. Heck, it took 7 months just to re-do Ise to a BBCx so she could launch (but not recover) a total of 21 planes, most of them floats.

All that “Capital” conversions do is put your capital ships in the shipyard for 2 years or more, after which they aren’t as capable as a purpose built ship, and your gun power has just gone away.

Nope, bad idea. If your mod’s world view supports the time, materials, resources to convert a BB to a CV, it will certainly support building a CV from scratch. That would be both cheaper, and less time consuming.

I the mode I consider japan should have the option to go extremes if She looses so many Cvs as in real life. But 2 year conversion time is realistic and it is beyond the scope of game.

Still 4 fast hard to destruct 72 plane BBs would be hard to resist.

In reality Kongos are as good as they get when they dont meet any real opposition. Even with their high exprience level. As in real life they are fragile.

I would consider 3 yamamotos and two mutsu is fair play in any confortation. I dont thing kongos had any help in real life escorting the KB. finishing the third as BB and converting 4 BBs to CVs could be materially cheaper then converting Shinano.

[JWE]

ORIGINAL: guctony
I the mode I consider japan should have the option to go extremes if She looses so many Cvs as in real life. But 2 year conversion time is realistic and it is beyond the scope of game.

Still 4 fast hard to destruct 72 plane BBs would be hard to resist.

Yes. But there's a big difference between building out a partially finished hull and cutting down and reconfiguring a completed and operational BB.

finishing the third as BB and converting 4 BBs to CVs could be materially cheaper then converting Shinano.

Yes and no. Converting 4 BBs to CVs would be way more expensive, in time and materials, than building 4 more Unryus from scratch. But definitely finish Shinano, a year early, as a BB, and turn her slip to build "Unuryu 30?". In '43 I would not at all mind a BatDiv of Yamato, Musashi, Shinano floating around, with the possibility of another Unryu popping out of the yard in 6-9 months.

I would keep the BBs. Build Shinano as a BB and use the BB yard conversion times to accelerate more Unryus.

Just my own opinion.[;)]

[PaxMondo]

When would the Shinano have entered service IF she had kept going as a BB instead of converting to a CV?  early 43?
 

[msieving1]

ORIGINAL: PaxMondo

When would the Shinano have entered service IF she had kept going as a BB instead of converting to a CV?  early 43?

Yamato and Musashi both took about 4 1/2 years from being laid down to becoming operational. Shinano was laid down 4 May 1940, so assuming the same amount of time, she would have entered service about December 1944. If anything, conversion to an aircraft carrier probably sped up her completion (though she was far from ready for service when she was sunk).

[Nikademus]

ORIGINAL: JWE

Yes and no. Converting 4 BBs to CVs would be way more expensive, in time and materials, than building 4 more Unryus from scratch. But definitely finish Shinano, a year early, as a BB, and turn her slip to build "Unuryu 30?". In '43 I would not at all mind a BatDiv of Yamato, Musashi, Shinano floating around, with the possibility of another Unryu popping out of the yard in 6-9 months.

I would keep the BBs. Build Shinano as a BB and use the BB yard conversion times to accelerate more Unryus.

Just my own opinion.[;)]

Agreed. The Unryu's were designed to be quick cheap light fleet carriers derived from the Hiryu/Soryu type. Far easier to mass build in theory than taking a completed warship like a battleship, stripping it down and rebuilding it like the Bionic Man and Woman.

Either way there still remains the issue of producing the planes and the pilots to man the additional carriers.

[Shark7]

ORIGINAL: JWE

ORIGINAL: guctony
I the mode I consider japan should have the option to go extremes if She looses so many Cvs as in real life. But 2 year conversion time is realistic and it is beyond the scope of game.

Still 4 fast hard to destruct 72 plane BBs would be hard to resist.

Yes. But there's a big difference between building out a partially finished hull and cutting down and reconfiguring a completed and operational BB.

finishing the third as BB and converting 4 BBs to CVs could be materially cheaper then converting Shinano.

Yes and no. Converting 4 BBs to CVs would be way more expensive, in time and materials, than building 4 more Unryus from scratch. But definitely finish Shinano, a year early, as a BB, and turn her slip to build "Unuryu 30?". In '43 I would not at all mind a BatDiv of Yamato, Musashi, Shinano floating around, with the possibility of another Unryu popping out of the yard in 6-9 months.

I would keep the BBs. Build Shinano as a BB and use the BB yard conversion times to accelerate more Unryus.

Just my own opinion.[;)]

Correct me if I am wrong, but couldn't Japan have completed a new Unryu class in about the time it would have taken to convert a BB?

The way I see it, BBs, while tough were built to fight other BBs, it would take a major reconstruction of the inside of the ship to handle aircraft, and you would be constrained by the dimensions of the existing hull. It is probably far less efficient a design than the Unryu class would have been.

But that is just my way of thinking.

[el cid again]

According to Cruisers of the Imperial Japanese Navy, this was indeed done. ALL the gunships of the Navy were considered for modification to carriers - CV or CVL. The older battleships were considered too slow for really effective carriers. The new fast ones were considered too valuable - there MIGHT be a surface fight after all. According to the book, there were three different designs for every battleship - a semi-carrier removing only rear turrets (which was done in the Ise class case), a semi-carrier removing amidships guns as well - and a full conversion. Note that the semi-carriers carried two different kinds of planes - bombers that coult not return and had to go to land or a different ship - and fast float bombers that could be recovered with Hein Mats while the ship was underway.

Apparently all the full conversions ended up with an aircraft capacity of 60 - that would be, however, of the newer, heavy aircraft then contemplated - and corresponds to about 72 if early war types were used. The most satisfactory choice might be the Kongos - on speed grounds - but in that case there would be no fast battleships that could keep up with the carrier force. But even a 25 knot CV is not useless - see for example the Hiyo and Junyo - which almost never made the speed for which they got new engines during conversion.

[James Fennell]

I agree with these posts - once a BB is completed, reconstruction as a CV is about as time-efficient and costly as building a new CV from scratch (and you lose a BB into the bargain) - a lot of deconstruction to do first. The BB conversions are either from the WWI programmes that were cancelled in 1918 (Akagi, Kaga, Lex, Sara, Eagle, Glor, Cour, Bearn) or from hulls diverted in from completion in WW2 - shinano, US CVLs etc. the Chitose AVs had been designed for a quick conversion - to deal with treaty limits. So much better to look at hulls awaiting completion. A possible exception is if a BB/BC is so badly damaged that it requires complete reconstruction - but that would take forever!

[herwin]

ORIGINAL: Stringbag

I agree with these posts - once a BB is completed, reconstruction as a CV is about as time-efficient and costly as building a new CV from scratch (and you lose a BB into the bargain) - a lot of deconstruction to do first. The BB conversions are either from the WWI programmes that were cancelled in 1918 (Akagi, Kaga, Lex, Sara, Eagle, Glor, Cour, Bearn) or from hulls diverted in from completion in WW2 - shinano, US CVLs etc. the Chitose AVs had been designed for a quick conversion - to deal with treaty limits. So much better to look at hulls awaiting completion. A possible exception is if a BB/BC is so badly damaged that it requires complete reconstruction - but that would take forever!

Mogami.

[James Fennell]

true - but Mogami like the BB semi-conversions did not involve re-trunking the boilers and cutting down to build new hangers and all that nasty stuff - just clear off the quarterdeck, pull up the turrets and put a box on - ahhh...errr. that's quite a lot too....[&:]

[el cid again]

ORIGINAL: Stringbag

I agree with these posts - once a BB is completed, reconstruction as a CV is about as time-efficient and costly as building a new CV from scratch (and you lose a BB into the bargain) - a lot of deconstruction to do first. The BB conversions are either from the WWI programmes that were cancelled in 1918 (Akagi, Kaga, Lex, Sara, Eagle, Glor, Cour, Bearn) or from hulls diverted in from completion in WW2 - shinano, US CVLs etc. the Chitose AVs had been designed for a quick conversion - to deal with treaty limits. So much better to look at hulls awaiting completion. A possible exception is if a BB/BC is so badly damaged that it requires complete reconstruction - but that would take forever!

While this is perfectly true, it ignores that Japan does not have the steel or the engine plants to do new builds in the sense the US might contemplate. An it also ignores that, while the hulls were indeed old, these ships had relatively new engines after very exhaustive reconstruction. And Japan was desperate after losing its four big carriers at Midway - so it looked at the concept - and indeed did convert two of these BB into semi-carriers - a cruiser into a semi carrier - another into a light carrier - and Shinano into a carrier as well. These historical efforts - plans and in some cases implemented plans - show the CONCEPT is a valid one. Also - under wartime conditions - build times were indeed accelerated - and there were plenty of inefficiencies to improve upon (Japan did appoint an economic tzar to do some of that - as did Germany - and it might have done so sooner than it did). The whole question is "is this economic or wise" is somewhat moot: war is not economic or wise to begin with. Once one accepts that Japan is at war - it must do something. An open mind ought to consider conversions. A battleship is NOT worth as much as a carrier in combat - and the real problem is how to get that into the thick skulls of Japanese naval leadership? After that, Japan ought to do something about pilot training - or it will end up (as really happened ) with carriers but no effective air groups. Games permit us to examine the possibility such issues might have been addressed.

According to Cruisers of the Imperial Japanese Navy, the full carrier conversions were thought to require about 18 months. If you have that much time in your game situation, it is a feasible concept.