Bismarck construction flaws

[yellowtail3]

Alecsandros makes a pretty good argument that the Bismarck & Tirpitz were the most capable European battleships in service in WW2, by some measures.

[RF]

On an individual ship basis I don't think there is any doubt that they were capable. But there was still room for some improvements.....

[ede144]

I'm curious what the improvements would be?
Regards
Ede

[yellowtail3]

I'm curious what the improvements would be?

It's too late now, but if I were asked then... I'd say, replace that secondary with a battery of 5"/38s, install a 16" main battery, tuck in a more efficient 600 pound steam plant and paint over that unsightly swastika on the fantail - but keep everything else.

[Dave Saxton]

It’s interesting that Bismarck’s 15” guns are somehow being represented as a design flaw.

Range Penetration
18km 442mm
20km 412mm
21km 392mm
22km 378mm
24km 350mm
25km 335mm
26km 320mm
28km 294mm
30km 275mm

That’s the intact penetration of the Bismarck’s 15”. That’s almost 11” of top quality armour all the way out to 33,000 yards. More importantly at the battle ranges where belt hits are more likely it is more than a typical 16”/45 firing an extra heavy projectile. Of course the typical 16”/45 will likely give greater deck penetration at extreme battle range. Nonetheless, a very important parameter for deck penetration amongst battleship caliber projectiles is striking angle. For example a 1030kg projectile and the 800kg projectile have about the same deck penetration striking 60* from the normal. This makes for an interesting comparison between using 8x15” armament or an 8x16” armament for the Bismarck class design.

The Germans had 16”/52 guns they could have used. It fired an 1030kg projectile at a similar velocity to the 15” 800kg projectile they used. Since the 16” projectile was heavier it would retain more velocity farther down range. This would mean that it would also retain a flatter trajectory out to a greater battle range; while the 800kg projectile will loose more velocity by the time it reached far down range, and therefore obtains a steeper angle of fall sooner. The 1030kg projectile would eventually gain greater deck penetration than the 800kg projectile, but such angles of fall would not occur until more extreme battle ranges. By using the 15” they could attain better deck penetration at somewhat shorter battle ranges, and still have excellent belt penetration.

By using 15” guns they needed to expend less tonnage in support, freeing up tonnage for other important priorities. Furthermore, we know from the records that a 16” gun was seen as political liability during the 1930s. They were not giving up much if anything either politically or militarily by going with the 15” gun.

[alecsandros]

By using 15” guns they needed to expend less tonnage in support, freeing up tonnage for other important priorities. Furthermore, we know from the records that a 16” gun was seen as political liability during the 1930s. They were not giving up much if anything either politically or militarily by going with the 15” gun.

Freeing weight. That must have been their top priority...
The ship was already 42000tons heavy. An increase in gun caliber meant an increase in turret size, barbette size, etc.
The ammo supply would also weigh more, considering the same number of main shells would be transported.
Offering protection against the ship's own guns would be even more problematic, and weight consuming.

[after all, Bismarck was not imune to 38cm gunfire at 20km. Everything above the main armor deck was vulnerable to 38cm Sk34 firing all the way to 25km range. Thus, equping her with the 16"/L52 would probably mean an overall increase in tonage of at least 4-5000 tons, taking the ship at 47000 tons nominal, and 57000 tons fully loaded. The max draft would increase from 10,3 to at least 10,6, if not 11meters, posing dangers in the navigation of canals around German harbor facilities.]

Other than that, 16" gives better T/D ratio against all WW2 battleships armor schemes, and creates a more damaging explosion if the shell works correctly.

And, especialy considering the evolution of radar and fire control in the 1941-1943 time frame, a 25km battleship battle was beginning to be much more realistic than in was in 1938-1940. AT 25km, the 16" has considerably more deck penetration than the 15"...

---

What is surprising though, is that ALL European battleships of the 30s-40s yielded 15" guns or less.

Probably the weight constraint forced them to do so...

[Dave Saxton]

AT 25km, the 16" has considerably more deck penetration than the 15"...

No, that's not the case here. Although I don't agree that the numbers from this data set are entirely correct, they are taken from the same computor model data set, and therefore useful for comparison purposes:

Deck penetration 25-31km..16"/52.......15"/52
.....................25km....89mm.........87mm
.....................28km.....102mm.......104mm
.....................29km.....114mm.......122mm
.....................31km.....130mm.......140mm

Moreover, against belts the penetration at 20km of the 15" is within 6% of the 16"/52, and it is 8% better than the American 16"/45 firing the 2700 lb projectile.

You would have to extend the battle range to beyond 34km (~37000 yards) before the deck penetration of the 16"/52 is significantly better. If the muzzle V is reduced, to achieve better deck penetration at shorter battle ranges, then belt penetration is sacrificed to less than the 15" gun.

[Karl Heidenreich]

Dave and Alecsandros,

Thanks for your interesting, objective and researched posts that helps understanding battleship design and throws away subjective and unnecesary biased comments from others.

Freeing weight. That must have been their top priority...
The ship was already 42000tons heavy. An increase in gun caliber meant an increase in turret size, barbette size, etc.
The ammo supply would also weigh more, considering the same number of main shells would be transported.
Offering protection against the ship's own guns would be even more problematic, and weight consuming.

In order to understand this we must see how "flawed" were the design arragements of the treaty battleships with a 35,000 ton limit displacement: the Nelson Class, the North Carolina and South Dakotas Classes in which armor and machinery were greatly sacrificed to have the 16". We see how, later, the british are keen to abandon the 16" in order to install 14" in their more modern and balanced KGV Class. In the US the problems with this still persist in the Iowas which is why a new class, the Montanas, came with a complete new approach in armor than it's previous cousin.

Also we have that Bismarck artillery was in double pairs front and aft which is the ideal that the artillery experts were more keen to use.

During the last years many of the so called flaws of Bismarck have been proved that they are not so and, surprisingly, these can be attributed to some of her contemporaries.

[alecsandros]

AT 25km, the 16" has considerably more deck penetration than the 15"...

No, that's not the case here. Although I don't agree that the numbers from this data set are entirely correct, they are taken from the same computor model data set, and therefore useful for comparison purposes:

Deck penetration 25-31km..16"/52.......15"/52
.....................25km....89mm.........87mm

Other calculations give roughly 4.4" average deck penetration of 16"/L52 shell at 28000 yards (25.4km).
Same program predicts about 4" average deck penetration of the 15"/L52 at the same range.

Beyond that range, indeed the 15" shell perforates gradualy more armor, probably because it wold be closer and closer to the end maximum trajectory (36km).

So, indeed, it's not much of a difference.

Cheers,

[yellowtail3]

During the last years many of the so called flaws of Bismarck have been proved that they are not so and, surprisingly, these can be attributed to some of her contemporaries.

FWIW, I don't think the German navy's choice of main battery was a 'flaw'

In order to understand this we must see how "flawed" were the design arragements of the treaty battleships with a 35,000 ton limit displacement: the Nelson Class, the North Carolina and South Dakotas Classes in which armor and machinery were greatly sacrificed to have the 16".

(SHRUG)They weren't any more 'flawed' than Bismarck, armament-wise - just diff priorities. I didn't know that the North Carolinas sacrifice all that much, power plant-wise, to have 16" guns. Where they going to devote a lot more space and tonnage to the power plant before the decision to switch from 12x14" to 9x16"?
I think the SD had a bit more power than NC, about the same as KGV. How much more power did the Brit ships make?

I think the trade up to 16" guns with much heavier shells than the Euro competition was probably a good move.

Also we have that Bismarck artillery was in double pairs front and aft which is the ideal that the artillery experts were more keen to use.

well, fans of that arrangement might be keen to use it... The US, British, Japanese, Italian, and French designers all came to a diff conclusion for their new ships. On that subject... I surfed over to Navweaps... comparing the weight of Bismarck's main battery to Iowa's, she only save about 500 tons all total by having 15" guns - heck, they'd have saved 500 tons by going 3x3 16/45s. It hardly seems worth it, to settle for one less gun and shells nearly a thousand pounds lighter than the competition, in order to have the old-fashioned four turret arrangement. I just added them up, didn't figure diff in ammo stowage - probably an extra 500 tons? Use the armament of the NC, and it's a wash, weight-wise. I understand the German navy favored lightweight shells?

[tommy303]

I think the main weight savings would have been achieved through shortening the citadel so it had only to accommodate three triple turrets instead of four twins.

[ede144]

Honestly 9 guns in 4x2 turrets, combined with the exelent fire control systems,optics and radar gives an excellent package. One needs not only big guns but also the means to get the bullets in the target.
Which could not said from all ships.
Regards
Ede

[yellowtail3]

Honestly 9 guns in 4x2 turrets, combined with the exelent fire control systems,optics and radar gives an excellent package. One needs not only big guns but also the means to get the bullets in the target.

Well... I'd say that 9 guns in 4x2 turrets - what is that, three twins and a triple? - is a waste on tonnage, when the same can more economically acheived in 3x3 (which is probably why all nine-gun ships had three turrets)

Bismarck's guns were fine. It she'd have hit anything in her last battle, they'd have an even better reputation!

[ede144]

The 9 was a typo error. And the last battle of BS was difficult for fire control because they could not steer asteady course. Nevertheless was Schneider able to straddle Rodney. Would not a lucky hit destroyed the coning tower. Maybe some hits on Rodney whould. And later on KgV would have shown, that it was not the easy going win it may looks like today.
Regards
Ede

[Karl Heidenreich]

ede144:

And the last battle of BS was difficult for fire control because they could not steer asteady course. Nevertheless was Schneider able to straddle Rodney. Would not a lucky hit destroyed the coning tower. Maybe some hits on Rodney whould. And later on KgV would have shown, that it was not the easy going win it may looks like today.

Correct. It is more than we can say during Truk where two Iowa Class battleships, fully operational, where unable, with combined fire, to sink a lonely destroyer Nowaki or the South Dakota poor performance during II Guadalcanal using radar and still being unable to hit anything from a enemy-filled enviroment.