AC Blucher: Best role for this warship?

[Graf von Spee]

Blucher seems too slow to fight enemy light cruisers and too lightly armored to be in the Hochseeflotte Battlecruiser fleet.

What role is she best suited for?

I wonder why they only made one of her class? Maybe she was a bad design?

 

[saddletank]

She works best I would think in the screen as a heavy backup for the KM CLs if they meet RN ACs. The other KM ACs likewise.

In the campaign you could try using her as a raider as the only thing she need fear is a BC.

 

[RAMjb]

Blucher seems too slow to fight enemy light cruisers and too lightly armored to be in the Hochseeflotte Battlecruiser fleet.

What role is she best suited for?

I wonder why they only made one of her class? Maybe she was a bad design?

The reason why you're asking for which is a good role for it is the very reason there was only one made. Blucher was bassically a mistake. Germans designed her as a counter for the Invincibles, problem is they got the intel all wrong; they thought the Invincibles were going to be armed with the same 9.2 inch guns the previous ACs carried. So they designed Blucher as a counter in the same way they designed the Nassaus as an answer to Dreadnought: smaller caliber for the main battery as a tradeoff for better armor. And then they found out that Invincibles were going to carry the same 12'' main battery as the dreadnoughts did, and were going to be almost as fast as a CL, but all too late for a redesign. As completed Blucher was an oddity, an Armored Cruiser designed to counter a class that totally outclassed her.

As it is I can't think of a viable role for this ship other than as a heavy scout for the HSF. She can easily wipe out british CLs and has a director since jan 1st, so as part of the scout van it can be a good ship. But in the Battlecruiser Force she simply drags down the battlecruisers as she is not fast enough. And as a raider, well, yeah, all she has to worry about is the british BCs...but if she gets caught by just one of them (and it's not as if it's an unlikely event), she's nothing but cannon fodder.

 

[saddletank]

You're painting a far too bleak picture of this excellent ship. Firstly I think the "wrong intel" story has been debunked as a myth. I think Blucher was designed as an 8.2" all big gun cruiser right from the start, a perfectly natural progression onwards from the Scharnhorst class. People think she's a white elephant because she got sunk at Dogger Bank and that she "slowed Hipper down".

The slowing down concept can be set aside considering that in late 1916 Hipper could only put to sea with Moltke and Von der Tann while Derfflinger and Seydlitz were repairing their Jutland damage. Scheer added Bayern and two Konigs to Hipper's force, all of which were a full knot slower than Blucher. Had Hipper encountered Beatty with this squadron what would the comments about Blucher being too slow have been? Not worth much I don't think.

Blucher had the longest ranged guns of any ship at Dogger Bank and she had a central fire director as well, something every other ship lacked. Just because she was sunk, that gives us a statistical sample of 1 to analyze which is useless. She was hit by a couple of very lucky serious strikes early on that both reduced her speed and caused a very bad fire. There is no reason at al why she should not have survived that battle.

In the SES 1915 campaign I think she'd make a perfect raider. Firstly she can outrun even an I Class BC (they are 25 kn vs her 24) but if she is caught in good visibility of 30km or so then there is no way they can catch her in a day, so to actually be certain of catching her the RN have to either divert a lot of DDs and swarm her en-mass and accept losses or detach from Beatty at least 1, possibly 2 Lions, and even then there is no guarantee she'll be caught.

Being a raider isn't only about sinking cargo ships, its about leading your enemy a merry chase around the seas as well, and even if Blucher just skulked about off Ireland for days and days the resources needed to hunt her down could be huge.

So with Beatty weakened for possibly several weeks this gives Hipper a huge advantage and who knows what kind of effect that might have.

In the campaign also the British ACs are very useful ships for slaughtering (or at the very least pushing in) KM CL screens. Blucher (and to a lesser extent Prinz Heinrich which is the only other KM AC in the campaign) nullify this advantage so Blucher either in the SG screen or acting a raider is a very useful ship.

If the German BCs meet only I class BCs then Blucher would still be a very useful ship to have in the line.

 

[thewood]

That is excellent analysis. I was wondering the same thing.

 

[martin worsey]

A good question but it depends on the circumstances: -

• In game – for shredding light forces when they have limited opportunity to escape (e.g. at night). From what I have read, this would not be a good use in reality.
• In reality as launched – she was one of the fastest things afloat so pretty much any task use you would care to put her to apart from trading broadsides with battleships. The only thing she need fear is maybe an Invincible.
• In reality during the war – she is obsolescent by this time so usefulness is limited:
1. As a battlecruiser but her lack of speed will slow the squadron.
2. As part of the screen for the main fleet (much like the British AC’s at Jutland). Usefulness would be limited.
3. To look impressive and “show the flag” overseas.
4. In the reserve.

The actual usefulness of the AC in general has been intriguing me of late. One way to look at naval combat is that there is no one size fits all gun available. A large 12” gun is satisfactory for fighting battleships which would typically have medium-heavy comparative armour, ideal for fighting AC’s with typically light armour and not so good for fighting largely un-armoured light cruisers and destroyers. Similarly a medium AC gun is ok against other AC’s but ideal for use against light cruisers.

The presence of lots of AC’s would limit LC’s to operating in close consort with the fleet as “eyes” but preclude any other role. Along comes Invincible, no more AC’s are built and the modern LC (which can out run an old AC just as well as a BB) suddenly lack any natural predator and expands into the available niches such as raiding and become the most useful and versatile units in the fleet. The only real counter would be battlecruisers which are expensive, over gunned and not necessarily fast enough to run down an LC.

This is fine to some extent but the AC whilst powerful, fast and well armed is also hungry for coal; this limits its usefulness as a commerce raider as it will struggle to capture enough to keep it going then will need to return to port. A light cruiser would be much better in this role as it is cheaper and more likely to capture sufficient merchants to satisfy its coaling requirements. The only proviso is that it should ideally be fast enough to run away from any large enemy warship that troubles it. The AC’s heavy armament is expensive in terms of cash and displacement but in the context of commerce raiding something of a luxury; operating far from base, you would not want to be getting into brawls with enemy warships which can damage you (curtailing your raiding) and will likely as not be hunting you in packs.

AC’s as part of the screen for the main fleet would appear something of a luxury as they cost as much as a BB.

 

[rgreat]

Blucher is CL butcher.

Detach it from the rest of BC and she can sunk alot of CL's, or even AC's while KM BC's deal with RN BC's.

 

[thewood]

So is the conclusion that an AC is tactically useful in some areas, but strategically, you might as well have built more CLs or a BC.

Are AC's the ancestor of the WW2 Heavy Cruiser?

 

[martin worsey]

Are AC's the ancestor of the WW2 Heavy Cruiser?

A matter of opinion but I would say not.

The WW2 8” cruiser was built in response to the London Treaty which placed a 10,000 ton limit on cruisers. As the Washington Treaty allowed for a holiday in BB production, the worlds navies entered into a mini arms race producing the most powerful 10,000 ton ships that they could. Quite what the military function of such a ship should be appeared to escape them.

 

[Bullethead]

The WW2 8” cruiser was built in response to the London Treaty which placed a 10,000 ton limit on cruisers. As the Washington Treaty allowed for a holiday in BB production, the worlds navies entered into a mini arms race producing the most powerful 10,000 ton ships that they could. Quite what the military function of such a ship should be appeared to escape them.

Quite true. The Washington Treaty's definition of max cruiser size and gun power was written around the just-completed RN Cavendish-class, the biggest things then existing under the name of "cruiser". But the problem was, these extra-large CLs were never intended to be part of the main fleet. They were conceived as a solution to the 1914 problem posed by von Spee's squadron. Then, the RN not only had to detach many modern CLs to deal with raiding, older CLs, but also BCs to deal with raiding ACs. The idea behind the Cavendish-class was that these ships could do both of those jobs themselves, letting the fleet keep its CLs and BCs.

But despite the fleets not really wanting or needing cruisers this big, because the treaty now specified an upper limit, everybody realized that anything short of that limit would be outclassed if somebody built such things and attached them to his fleet. Thus, everybody started building Treaty Cruisers simply to keep up with the neighbors, not because they really wanted such things. And then, of course, folks realized that you could mount 12-15x 6" guns on such a hull and have a better ship anyway, plus exploit a loophole in the treaties.....

As for how to use Blucher, she's good at keeping RN CLs at a respectful distance but her guns are only effective against even I-class BCs and RN ACs at relatively short range. Cats and even predreadnoughts can pretty much ignore her existence. She can outfight a single RN AC in most categories, but RN ACs come in bunches and aren't that inferior to her ship-for-ship, so if an RN AC squadron catches her out raiding, things probably won't go well for Blucher.

So I see Blucher as most useful in fleet actions. She can keep the RN from pushing in the HSF's screen with just CLs, forcing them to bring up ACs or BCs, and therefore putting these high-value uints at greater risk.

 

[mariandavid]

The only WW2 German vessel that Blucher matches in concept and intended usage are the Graf Spee 'heavy' cruisers . As some commentators have pointed out to treat her as a 'failed Invincible' is incorrect. She was designed as the successor to the Scharnhorst pair and had flag quarters and fuel space to serve as a group command ship in the Far Eastern Squadron. The jump in gun size was a response to the British introducing it for their heavy cruisers (the gun makers claimed that the 8" of the Scharnhorst's were equal to the 9.2, but the sailors disagreed!). When the details of the British BC's were discovered construction continued, if only because the slip being used could not yet be used for a bigger ship.

As for her usage I have (I admit only twice so far!!) placed Blucher 5000 - 15000 yards/metres ahead of the lead HSF battleship. As pointed out she can then handle any LC approaching and can resist any AC. Once the enemy battle-fleet is determined and action is accepted, move her to the 'sheltered' side, some 3000 yards out and level with the lead BB. Here she is safe and her speed will allow her to advance and damage any DD or FL torpedo attacks coming in from the forward arcs of the fleet.

 

[Cradock]

I'd say mariandavid has tactics and uses for Blucher in the HSF about right - I'd maybe push her out a bit further in terms of starting station. She's powerful enough to do serious harm to many light forces she might meet and speedy enough to run back behind cover of the main battle line if she doesn't like the look of what she's meeting. I have once or twice popped a sole BC into that position if say I have a couple of BC's under repair so am not putting the whole BC force to sea in support/pathfinding role for the main fleet.

I think the sole raider tactic also works.

 

[delcyros]

Guessing from her armour protection scheme, SMS BLÜCHER is well armoured for a cruiser. In most conditions from medium range (12,000 yard - 16,000 yard) she should be relatively safe against 12in soft capped APC such as historically used by the INVINCIBLE´s. Her side armour is extensive in coverage and the thickness and even the upper side belt is in within medium armour thickness range (0.52 cal for a 12in), which would be very difficult to defeat with period 12in (crappy..) APC -the main armour belt is even more difficult to defeat (=0.59 cal thickness).
13.5in APC are just able to achieve penetration against the upper citadell belt (0.47 cal thickness plate for the 13.5in APC) but very rarely against the main belt unless ranges are shorter (=0.52 cal thickness, about as problematic as a 15in APC defeating a 200mm belt and burst behind- which happened only once at Jutland) and this expectation is mirrored in DOGGERBANK when 13.5in defeated the upper side belt at medium range and started a serious fire in BLÜCHER´s ammunition passageways. The latter may be considered as a design mistake but a quite common one in this timeframe (the US NEW YORK and TEXAS dreadnoughts featured exactly the same passageways for ammunition).
BLÜCHER´s guns outrange INVINCIBLE´s by a considerable margin. At long range and with central director firecontroll, BLÜCHER may even be able to defeat the thin, laminated armour decks of the INVINCIBLE´s and INDEFATIGABLE´s even while it is equally unlikely that BLÜCHER´s main guns can defeat the BC´s side armour at medium and long range.
I would expect that a BLÜCHER and a INVINCIBLE at medium range would empty their magazines for little effect against each other while at long range BLÜCHER has some advantage and at short range both can work over each other in relatively short timeframes.

 

[RAMjb]

thats a decent analysis of the respective armored setups of Blucher and "I"s, delcyros. However you forget to mention one, key, point here. Blucher was good to steam at a speed of 24 knots, 25 in best conditions and extracting every single shp possible from their machinery. "I"s could reach 25 knots top speed, 26 (or even a bit more) when hard pressed for top speed.

The "I"s would decide the range, and it's clear that they would chose to fight at the closer, the better (as was seen with the german ACs at the Falklands). And that is the trump card for the british ships: not only bigger guns, but also a higher top speed to decide the range of the fight. Blucher could have a good armor for her size and class, but still would be quite hard pressed to stop 12'' shells (faulty caps or not), her best range would be a non-factor given that she couldn't decide the range of the fight, and her main guns weren't exactly adequate to deal even with the very lacking armor setup of the I's.

For me there's no real contest between both ships, even while it might be a much closer matchup than what it might look at a first glance.

 

[martin worsey]

Guessing from her armour protection scheme, SMS BLÜCHER is well armoured for a cruiser. In most conditions from medium range (12,000 yard - 16,000 yard) she should be relatively safe against 12in soft capped APC such as historically used by the INVINCIBLE´s. .

Delc,

Presumably this analysis applies to the 1914/15 time frame when both types are somewhat obsolescent. At time of launch she would presumably be firing crappy 8” shells which would struggle to penetrate much over 4” of armour at medium range which needs to be considered in a balanced assessment of her design capabilities.

I think you mentioned in a previous post that these ships were designed to fight at close range and this seems to confirm it.

 

[Slider6]

Great discussion. I like Mdavid's use and concept for the game and works well.

The published sources I have all say though the blucher was designed for 24knts it reached 25.4 knots in trials. Some of the german BB's speed was changed due to data from trials, what is the logic/data for leaving blucher at 24knts? I guess I was thinking it would show up as a 25knt ship.

 

[PongoDeMer]

I came up against her placed in the German line in the scenario "Fogbound". She didn't last long and I would conclude from his (and what happened to her at Dogger Bank) that she would have been a complete liability as line-of-battle ship. On the other hand, I would argue that she would have made a superb commerce raider. Let us remember that Scharnhorst, Gneisenau and the Emden's principal effect was not only measured in terms of tonnage sunk, but also in the valuable resources diverted to hunt them down. While these German raiders were active, the R.N. was stretched to the limit.

Pongo

 

[mariandavid]

There was much debate over this between the wars in the new KM. The issue was cost-effectivenesss, the argument being that Von Spee and this cruisers though dramatic had less effect and cost much more than the 'proper'auxilary cruisers. By that was meant not the AMC but rather the smaller, hidden guns, powerful radio, very large radius of action and capable of concealment types. Be that as it may - as a commerce raider Blucher is far too big - what would be best is a light cruiser with a very large radius and enough speed to avoid all Allied AC.

 

[SMS Biene]

Here is some further detailled Information on SMS Blücher (and many other ships of the Hochseeflotte):

www.german-navy.de/hochseeflotte/ships/armoredcruiser/blucher/history.html

Perhaps you should send Blücher to the Baltic Sea, should Jutland once allow for that ... :smoke:

Regards
SMS Biene

 

[delcyros]

The "I"s would decide the range, and it's clear that they would chose to fight at the closer, the better (as was seen with the german ACs at the Falklands). And that is the trump card for the british ships: not only bigger guns, but also a higher top speed to decide the range of the fight. Blucher could have a good armor for her size and class, but still would be quite hard pressed to stop 12'' shells (faulty caps or not), her best range would be a non-factor given that she couldn't decide the range of the fight, and her main guns weren't exactly adequate to deal even with the very lacking armor setup of the I's.

For me there's no real contest between both ships, even while it might be a much closer matchup than what it might look at a first glance.

Top speed isn´t really that different here. INVINCIBLE´s top speed in peacetime trial conditions was 26.61 kts forced (INFLEXIBLE= 26.41 kts & INDOMITABLE= 26.11 kts) while SMS BLÜCHER logged in an average of 25.82kts in her 6 hour trials. Depending on which ship You relate this to, this makes for a difference of +0.29 kts to + 0.79 kts. The combat speeds would be less for many reasons, BLÜCHER was designed to sustain 24.5 kts while the INVINCIBLE design speed was 26 kts, which they were hard pressed to match.
BLÜCHER on the other hand would have been derated under german wartime trial rules and not able to achieve even 25 kts of her fastest run.

Dictating the range of the engagement is practically impossible with a mere kts speed difference. The GF considered in period sources a difference of at least 3, preferably 4 kts sufficiant to be of any tactical benefit.
Dictating the range is further impossible when You are heavily outranged by Your opponent. Remember, BLÜCHER´s 8.2in gun´s were able to engage out to 20,900 yards while INVINCIBLE´s 12in mk X with 2crh AP were only able to reach to 16,450 yards with new guns.
It takes about two hours at both ships max sustainable speed to bridge this 4,500 yards gap in a stern chase in which INVINCIBLE cannot respond to BLÜCHER´s fire. This is more than enough time to completely deplete BLÜCHER´s 85 rounds per gun containing main magazines for the stern and after wing turrets if shooting at a slow average of 1rpm (max possible: 4-5 rpm) in such a long timeframe.

I attempted to make a comparison for each others protection relying on Nathan Okuns facehd and M79 APCLC programs. Note that an long range engagement exposes the armour decks of the INVINCIBLE.

Presumably this analysis applies to the 1914/15 time frame when both types are somewhat obsolescent. At time of launch she would presumably be firing crappy 8” shells which would struggle to penetrate much over 4” of armour at medium range which needs to be considered in a balanced assessment of her design capabilities.

I think you mentioned in a previous post that these ships were designed to fight at close range and this seems to confirm it.

That´s true. Originally and to 1912, the BLÜCHER alike other ships were intended to engage enemy AC (bot not PDN´s, BC´s or DN´s) at very close range. This is also the reason for the 50mm KNC slope behind the 180mm armour backed by a coal bunker and another protected bulkhead. Enough to defeat 9in main calibre guns from even short range. They were given a large main gun elevation mainly in an attempt to create long range reach against shore targets for coastal raids not to faciliate long range naval gunnery.
But by the summer trials in 1911 and 1912 they conducted long range naval gunnery and found it feasable. BLÜCHER owing to the large gun elevation became the HSF´s main long range gunnery exercising cruiser and was the first eqiupped tripod and centralised firecontroll. It also stood in an ever lasting contest with ACR SCHARNHORST and GNEISENAU for winning the annual gunnery award. BLÜCHER on the prize in 1911 for beeing the best shooting ship of the entire HSF in that yaers manuever period. It pioneered the usage of gyrostabilization elements in gun mountings during 1912 and in 1913 received increased elevation spotting top with Siemens stabilized mountings and Zeiss stereoscopic rangefinder for long range cetral director shooting.
Originally, at long range only HE base fused or HE nose fused would be fired in order to derate the exposed equipments and unprotected ship ends. It was not before Krupp replaced it´s lyddite filler (Gr.f. 88 in german terminology) with wood plugged, block cast TNT and introduced hard armour piercing caps at about the same timeframe that AP long range fire became a viable option.
By the time of Doggerbank the ACR has changed to become a long range thread, it´s armour still sufficiant at this range unless very heavy calibre guns are fired at it (13.5in, 14in and 15in) and it´s guns, the firecontroll suite and the training level of the crew optimised for long range action.

At short range action (say, 8000 yards or less) BLÜCHER may still overpower an I-class by volume of fire of it´s 8.2in main and 5.9in sec. gns but unless it can claim a critical hit in a magazine, turret or barbette, I would still give the advantage to INVINCIBLE owing to the larger guns and larger size (size helps absorbing damage).


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edit: SMS BLÜCHER´s turret faces are not 7.1" but 9.8" thick, so take the figure of CT alike instead