Shipbucket

Hi all,

I'd like to discuss my idea for a battleship for Poland (in semi-historical setting). I am aware that there was no way to fit a BB in Polish budget in thirties, but let's strech it a bit

Do you think a such a refit was feasible? What would you change?

Background: One of the Mackensen-class BCs, SMS Graf Spee was built in shipyard in Gdańsk (Danzig). When the Ist World War ended, the ship was supposedly 12 months from completion. It was scrapped during 1919-1920.

My idea for this drawing is that Polish diplomats managed to obtain the hull of this ship as part of split of HSF in Versailles treaty. Throughout 1920s it stayed either in Gdańsk or somewhere along the Polish coast (Hel?) as a naval hulk ORP Bałtyk (replacing real ORP Bałtyk - disarmed french cruiser D'Entrecasteaux bought by Polish Navy in 1927).

In 1935, after signing a deal with British yard J. Samuel White in Cowes for the construction of four large destroyers* (future OORP Grom, Błyskawica, Huragan and Orkan) Department of the Navy began lobbying for further increase in funding, pointing to the threat of Soviet battleships and cruisers to newly built coastal infrastructure. At some point an idea appeared to finish construction of Bałtyk as a cheapest method of obtaining a ship that could fit the role. Those ideas were undoubtedly influenced by reconstructions of WWI vintage battleships that began in both UK and Italy. At first, the idea was rejected, even though questions were sent to French and British yards for drafts and costs. Over the next months enough popular support for the idea of Polish Battleship was gathered (along with some funds) that finally in autumn Government decided to yield to those demands and funding was secured. A British yard was chosen, and construction started in January 1936.

Completely new propulsion plant was fitted – Admiralty three drum boilers and Parsons turbines allowing her to reach 30-31kts. Bow was lengthened by new 10m long part added on top of old bow to increase L/B ratio and cover torpedo tube port in the original bow. Other underwater torpedo tubes were also removed and plated over, their compartments subdivided to remove the risk they posed in case of damage.
Deck armour was strengthened from 80mm(3,1in) to 5in over the magazines and 3,5in over the machinery spaces.

As the barbettes were already in place, new gun turrets needed to fit those (Mackensens were supposed to use 35cm guns). Proper 14in guns were just picked as armament of new British battleships (future King George V class) so a deal was made to use adapted twin turret that was planned for those ships. 16 dual-purpose QF 4.5in Mark III guns in twin BD Mark II mountings were fitted as secondary armament and heavy AA battery.
Light AA was composed of 10 twin 40mm Bofors guns and some twin 13,2mm Hotchkiss AAMGs as those were standard AA guns used by Polish navy at the time.

The plane is PZL-46 Sum, a prototype dive bomber built for the Polish Army in 1938, IRL it was used for tests and scheduled for series construction when the war broke out. I would love to use it as spotter for my BC, as PZL-46/hydro, Only I need to fit a catapult somewhere - either rotating catapult and a crane aft or cross deck catapult between turret V and X. Or maybe you can propose some better position I had not spotted?

*In reality the two latter were planned for construction in Poland starting from 1939.

This is an interesting concept. Can't wait to see what the result will be. I think it will look quite a handsome ship.

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15 years of being a hulk, I doubt hull would be in any shape to receive such treatment. In reality indeed, such ship would be far, far, faaaaarrrr beyond Navy budget. Handful of destroyers was pushing it to the limits. But ok, let's stretch that... a lot.

Also, PZL-46 was not a dive bomber. It would be more realistic to have R-XIII ter/hydro.

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Nobody expects the Imperial Inquisition!

True, but any other option would be completely impossible
Yes it was, as it would require cuts in other areas of military spending. Back then? Unacceptable. Today, with hindsight, I'd say it would be a good deal, as ships would fight on, while guns or tanks had to be left behind to be destroyed or captured.
And it wasn't that bad - pair of Grom-class DDs costed, according to wikipedia 520k pounds each, so a million for both. Refit of Renown costed 3 mil while new KGV 7 mil. OTOH it could be argued that 6-7 additional Grom class DDs (or 2 Grom and 8 smaller DDs) would probably help Allied war effort more than a single BC...
You mean PZL-46 was not a hydroplane (as it definitely was a dive bomber)? Yes, but could be turned into one as it was available in 1938 so there was time to do it.

Lublin R-XIII hydro was scheduled for retirement. It was to be replaced with Italian CANT-506B hydroplane (first of the order arrived in Poland just before the war). It would be more probable that the ship would be equipped with British plane, probably Swordfish rather than R-XIII.
R-XIII had crappy range (450km) compared to 1300km of PZL-46 on wheels. With floats fitted it would drop, but I don't think it would go below 800-1000, in line with for example Ar196.

No, I mean PZL.46 was not a dive bomber. It was updated version of PZL.43 with some gimmicks like lowered "bathtub". But it was not a dive bomber, he got the same bombard characteristics like Karaś. There was a prototype/demonstrator of such ability in form of PZL.42, but it is unclear if they even tested dive bombing, plane did not had moving bomb rack to move the bomb out of the propeller contour, dive breaks or automatic system to pull up. Because of that he would be able to "dive" only in 45 degrees angle. Hardly a dive.

Now, there had been plans to indeed build a dive bomber based on PZL.46 but it would be slightly smaller PZL "Łosoś".

Range would be a problem, yes. But it would be fast replaced by something Made in GB just for the sake of spare parts. So maybe Lublin is not a bad idea, it was after all still a main hydro in 1939.

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Nobody expects the Imperial Inquisition!

You are right, sorry. I was under the impression one of production versions was supposed to be fitted for dive bombing, but I could have mixed that up with Łosoś. Though it doesn't really matter here - with floats it would not be able to carry that much bombs (or perform any sharp manoeuvres )
Besides being totally obsolete and having abysmal range, I'm not sure R-XIII would survive operations in open waters.

Not to mention that Sum on floats look so much better

A nice concept, using a German old hulk with modern (for that time period, that is) British equipment. Problems like converging German metric standards in British imperial measurements seem minute beside the actual refitting and building problems.
...and on to your catapult, as you are using a modified British structure, why not do what the British did and place your catapult athwart-ship, and put two hangars around the fore-funnel? your drawing sure looks like you have the hangars there

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Thank you Kim for the crest

"Never fear to try on something new. Remember that the Titanic was built by professionals, and the Ark by an amateur"

Well, right, British measurements... Another can of worms... Maybe after finishing this I'd make a version as if refitted in Italy... The main question is: was it possible to fit Italian 305mm triples on barbettes of 35cm twins?

I would love to place catapult between funnels, but I think the planes were launched across deck, so they need to fit with unfolded wings. V turret instead of X occupy too much space for that. Only place for cross-deck catapult is the space between turret X and V.

You might consider moving the funnel backwards then. I'm not that knowledgeable about the Mackensen to give a really good answer. The fact is that warships are not really my forte, so to speak

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Thank you Kim for the crest

"Never fear to try on something new. Remember that the Titanic was built by professionals, and the Ark by an amateur"

Hi Archelaos
Instead to draw a polishised-Mackensen, totally unrealistic
Why do not you try to draw a polish battleship as it was intended

The real facts : Polish naval programmes 1920-1942

Russian Empire ships claimed by Poland in 1919-1921
- 2 Gangut-class Battleships
- 2 Svetlana-class cruisers (both unfinished)
- 10 destroyers
- 5 submarines

1st 1920 Plan (to be started around 1922/1924 & completed by 1928)
- 2 Battleships (these are NOT the Ganguts from above) (probable french or british or US design)
- 6 Light Cruisers
- 28 Destroyers
- 45 Submarines

2nd 1920 Plan (revision of the 1st 1920 Plan)
- 1 Light Cruiser
- 4 Destroyers
- 2 Submarines

1924 Plan (revision of the 2nd 1920 Plan, to be started around 1925/1926 & completed around 1931)
- 2 Light Cruisers
- 6 Destroyers (2 finally delivered)
- 12 Submarines (3 finally delivered)

1936/37 naval programme (what the polish admirals wanted)
- 2 Battleships similar to the 1938/39 one probably meant to counter the German Scharnhorsts
- 2 Heavy cruiser (10.000 tons, 3x3 203mm, 9 x 120mm AA guns, 4x2 Torpedoes, 100 000shp engine, 200mm Armour)
- 9 Destroyers
- 18 Submarines

1937/38 naval programme (what the polish admirals wanted)
- 3 Battleships (25 000 tons, 350mm Belt-armour, 120-140.000 shp engine, 3x3 305mm guns, 4x3 or 6x2 150mm guns, 2x3 Torpedoes)
- 1 Aircraft Cruiser probably similar to the Swedish Gotland cruiser
- 12 Destroyers
- 21 Submarines

Proposed Naval Plan of 1942 (probably studied by late 1938/early spring 1939, to be started at 1942 and completed around 1946-1948)
- 1 Battleship
- 1 Heavy Cruiser (15 000 tons, 3x3 203mm & 9 x 120mm guns)
- Severals Destroyers


In my opinion, try to draw :
- a 25 000-ton Polish battleship
- a 10 000-ton Polish heavy cruiser