Bismarck/Tirpitz = most powerfull European battleships

[Dave Saxton]

My copy of official Kriegsmarine Tirpitz drawings (a primary source) show 80mm panzer deck over non magzine areas, in Compartment XV.

[Dave Saxton]

Maybe some authors included the battery deck (20mm St52, situated 2.4m beneath the upper deck) in their description ...

The battery deck was nonballistic at 6mm.

[Thorsten Wahl]

if someone may investet $ 31,50 to a more modern study about yawed impact on thin plates
http://www.sciencedirect.com/science?_o ... 1492881b8c
but its for moderate obliquities
Description

Two experimental investigations and a corresponding analytical study were conducted to examine the phenomena attendant to the impact of blunt-nosed, hard-steel strikers on stationary thin plates of aluminum and steel at moderate angles of yaw and zero obliquity. The variation of ballistic limit with yaw angle or the terminal velocity and final trajectory angle in perforation tests were ascertained. Post-mortem examination of the plates indicated that damage and failure occurred by bulging, lateral indentation, and side and front petaling. A theoretical model based on a membrane representation was developed that analyzed the impact by dividing the process into five stages. This model underpredicted the ballistic limit by up to 14%, with better correlation found at higher yaw angles. Excellent agreement was observed between the experimental and analytical final velocities when the data points were corrected to reflect the difference between the experimental values of the ballistic limit and that predicted by the model. Fair agreement was found between the experimental and the analytical values of the trajectory angle

[alecsandros]

The battery deck was nonballistic at 6mm.

And wasn't there a 20mm deck between the upper and panzer deck at all .. ? (regardless of the name)

[Herr Nilsson]

No, there was just a 1 m stringer of 20 mm. The deck was 6 mm.

[Thorsten Wahl]

The battery deck was nonballistic at 6mm.

And wasn't there a 20mm deck between the upper and panzer deck at all .. ? (regardless of the name)

The upper platformdeck in front of the bow transversale bulkhead (Frame 202,7- 233,0)was made of 20mm Wh. It offers splinterprotection against medium caliber detonations at the Oberdeck to keep watertight integrity for the ship's hull below waterline.

[alecsandros]

Thank you very much, Thorsten.
You guys are helping me alot learn new things every day.

I appreciate very much your efforts, and hope I'll be able to return the favors some day.

Cheers,
ALex

[Dave Saxton]

if someone may investet $ 31,50 to a more modern study about yawed impact on thin plates
http://www.sciencedirect.com/science?_o ... 1492881b8c
but its for moderate obliquities

I have pages and pages of Goldstein on my old computor. It's rather like reading the Old Testament. The bottom line is that yawed impacts require more necessary velocity for penetration than the same projectile un-yawed.

[spicmart]

Hi, I'm just a layman. Maybe you can give me a clue about this question:
Did Richelieu have a better torpedo protection system than Bismarck? I thought Bismarck was renowned for her TDS. So what about it?
Could the Rich take more underwater damage than Bis? I know Bis had more protected reserve, reserve though.
Thanks

[Serg]

The designed resistance for the Bismarck side protection system was 250 kg of TNT and 300 kg for the Richelieu. But it is not known what actually are.

[alecsandros]

Did Richelieu have a better torpedo protection system than Bismarck? I thought Bismarck was renowned for her TDS. So what about it?
Could the Rich take more underwater damage than Bis? I know Bis had more protected reserve, reserve though.
Thanks

Bismarck had a waterline length of about 240m. The torpedo protection was nearly 170m long, so most of the ship's side's were protected against torpedo hits.
Richelieu had a similar waterline length, but the torpedo protection covered about 130m of the ship's length, leaving the bow and stern more vulnerable than in Bismarck's case.

The noteworthy mention regarding Richelieu is however that the main armored belt ran much deeper than Bismarck's. So although it's TDS was shorter, it was deeper than on the German ship.
The implications, IMO, are taht Richelieu could take more concentrated torpedo damage, while Bismarck could take more torpedoes spread along the length of the ship.

Cheers,
Alex

[Thorsten Wahl]

The implications, IMO, are taht Richelieu could take more concentrated torpedo damage, while Bismarck could take more torpedoes spread along the length of the ship.

No, any single hit on a segment of the torpedoprotection system will render this segement and probably adjacent segments potentially ineffective to following torpedoattacks because of flooding.

The main difference in my eyes is that the french system should be able to absorb bigger single warhead damage because of its depth with the prerequisite that the materials used for the bulkheads were of proper quality.

On the other side the external belt of bismarck offers some benefits to the protection as any non penetrating shell hit on the submerged parts probably don't render the torpedoprotection ineffective and shallow torpedohits on the belt will also not affect the TP System, additional the extensive watertight subdivision of the complete ship is a supportive feature of the german ship as well as its pumping capacity of around 16,000 t of water per hour.

The german Konstruktionsamt consider both systems as being roughly equivalent, recalling the mostly thicker bulkhead, but tend to use a deeper system for successor ships if size of installed machinery should allow this.

[Bgile]

As we can see from the PoW shell hit, the Bismarck system causes significant list when flooded because of the large outboard void spaces.

[spicmart]

What about Vanguard in a comparison to Bismarck/Tirpitz in an overview?

Thank you

[Thorsten Wahl]

The area outwards of the BS-torpedobulkhead was divided into 20 watertight sections in between 5,5 m - 8,5 m lenght each
roughly 40% of the space at the TDS was empty to accommodate detonation gases - average empty space roughly 82,5 m³ per section

A detonation of a torpedo with a 300 kg TNT warhead will create roughly 225 m³ of detonation gases.
225m³ of gas correspond to a bubble of 7,6 m diameter. The center of detonation is placed outside of the ships hull so "only" a half of the created volume affects a ship directly

If you look at detonation damage you can see 2 zones of damage

1) primary damage by creation of the "detonationbubble" almost complete removing of the earlier content with the speed of formation of the "bubble"
the earlier content got sharp acceleration and flys in every direction off center
there is nothing but only extremly rigid structures, wich are capable to withstand the direct detonation forces

2) secondary damage by the
a)shockwave,
b)further expanding detonation gases and
c)the accelerated "earlier contents" /debris/splinters from the warhead/hull
Its here where the various TDSprotection systems start

a and b directly transport destructive energy , the amount of available energy at the target is dependent on distance between center of detonation and target
there is a loss of destructive energy dependent on the cubic root of distance between center of detonation and target so double the distance will decrease available destructive energy by 8
additional you can affect the energyflow by changing the medium the energy is transported; in the best case you can almost completely disrupt or redirect the energy flow

c works partly in another way by comparision when a and b are light emitted by a light bulb c is a laser
the loss of energy for the laser is less dependent directly on distance but more dependent on interaction with the medium the light is going through

extensive research by the germans on real size targets and experience with innummerable mine- and torpedo explosions in WW1 reveal the fact that c was the most dangerous component
the result was 1 thick bulkhead placed as far as possible from the center of accident with a liquid layer in front of this bulkhead to catch and or slow down debris and splinters before hitting the bulkhead and only as few material as been absolutely necessary to form the liquid layer and sustain a necessary strenght of the hull of the ship.

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POW-hit
If the POW hit affects 2 sections of the TDS the expected flooding was ~165 t of water

but by the destruction of the torpedobulkhead because of the shelldetonation on the bulkhead brought an additional flooding of the boiler room of ~700 t
So most of the list was probably caused by the flooding of the boiler room