Bismarck speed during last battle

[RF]

It is an interesting scenario.

Whilst it may cause gunnery targetting problems for the British, I would have thought it would create even greater gunnery problems for the Germans in targeting any of the RN ships....

I presume that the faster Bismarck goes, the tighter the circles?

[Thorsten Wahl]

From the "Kreisfahrten" it appears that circle radius depends mainly on rudderposition
speed ~20 knot /10 knots
at 15 degrees the circle was approx 1000 m increased to 1075m at lower velocity
at 25 degrees the circle was approx 875 m decreased to 720m at lower velocity
at hard rudder the circle was approx 650m constant

but the slower the speed the later starts the turning
at 10 knots time until turning starts up to 1 minute
at 20 knots time until turning starts 25-30 seconds

maximum heeling angle at every rudder position 1,5 degrees for full turn
speed loss at low velocities and every rudder position max 2 knots
speed loss hat high speed and rudder less then 15 degrees 6 knots
speed loss hat high speed and hard rudder up to 11 knots

[paul.mercer]

Gentlemen,
This discusson on Bismarcks speed is very interesting, it seems to me as a not very well informed observer that her capabilities were something betweem 28 and 30 knots under good conditions, which brings me back to a question that I have asked before. Aftet her battle with Hood and PoW she had a hole in her bow through which she shipped around 2000 tons of water which would have slowed her down, after it had been patched up it appears that she still could not use her maximum speed for fear of the collision mats coming adrift and putting severe strain on her bulkheads, therefore by my uninformed opinion she could not have caught or overhauled PoW even if she wanted to as her maximum speed was the same or possibly a little less than PoW.
Or have I missed something!

[RF]

To continue the action with POW the Bismarck would not need to overhaul that ship but keep it under fire while within effective gunnery range. At longer ranges the shellfire trajectory becomes steeper so Bismarck would stand to score more damaging individual hits at longer range. The same would be true of POW, but its gunnery was degraded so the risk to the Germans is reduced.

The only reason for the Germans to close with POW is for the Prinz Eugen to launch a torpedo attack. However it would be unlikely that Brinckmann would close until the 5.25 inch guns on POW had been knocked out, for while the 14 inch guns weren't at full punching strength I gatherthere was nothing wrong with the POW secondary battery.

[alecsandros]

Gentlemen,
This discusson on Bismarcks speed is very interesting, it seems to me as a not very well informed observer that her capabilities were something betweem 28 and 30 knots under good conditions, which brings me back to a question that I have asked before. Aftet her battle with Hood and PoW she had a hole in her bow through which she shipped around 2000 tons of water which would have slowed her down, after it had been patched up it appears that she still could not use her maximum speed for fear of the collision mats coming adrift and putting severe strain on her bulkheads, therefore by my uninformed opinion she could not have caught or overhauled PoW even if she wanted to as her maximum speed was the same or possibly a little less than PoW.
Or have I missed something!

PoW was also damaged and took water 400-600 tons. Leech reported 26-27kts best speed after the battle.

[Dave Saxton]

To continue the action with POW the Bismarck would not need to overhaul that ship but keep it under fire while within effective gunnery range. At longer ranges the shellfire trajectory becomes steeper so Bismarck would stand to score more damaging individual hits at longer range. The same would be true of POW, but its gunnery was degraded so the risk to the Germans is reduced.

The only reason for the Germans to close with POW is for the Prinz Eugen to launch a torpedo attack. However it would be unlikely that Brinckmann would close until the 5.25 inch guns on POW had been knocked out, for while the 14 inch guns weren't at full punching strength I gatherthere was nothing wrong with the POW secondary battery.

A factor here could have been ammunition supply and the probabilities of scoring hits at long range/ APC ammunition expended. I'm sure Luetjens and Lindemann would have worried about this.

[alecsandros2]

To continue the action with POW the Bismarck would not need to overhaul that ship but keep it under fire while within effective gunnery range. At longer ranges the shellfire trajectory becomes steeper so Bismarck would stand to score more damaging individual hits at longer range. The same would be true of POW, but its gunnery was degraded so the risk to the Germans is reduced.

The only reason for the Germans to close with POW is for the Prinz Eugen to launch a torpedo attack. However it would be unlikely that Brinckmann would close until the 5.25 inch guns on POW had been knocked out, for while the 14 inch guns weren't at full punching strength I gatherthere was nothing wrong with the POW secondary battery.

A factor here could have been ammunition supply and the probabilities of scoring hits at long range/ APC ammunition expended. I'm sure Luetjens and Lindemann would have worried about this.

What long range ? PoW was as close as 13km to Bismarck...

[Dave Saxton]

I'm speaking to the idea presented by RF about extending the engagement against POW via long range gunnery rather trying to run it down.

[dunmunro]

Gentlemen,
This discusson on Bismarcks speed is very interesting, it seems to me as a not very well informed observer that her capabilities were something betweem 28 and 30 knots under good conditions, which brings me back to a question that I have asked before. Aftet her battle with Hood and PoW she had a hole in her bow through which she shipped around 2000 tons of water which would have slowed her down, after it had been patched up it appears that she still could not use her maximum speed for fear of the collision mats coming adrift and putting severe strain on her bulkheads, therefore by my uninformed opinion she could not have caught or overhauled PoW even if she wanted to as her maximum speed was the same or possibly a little less than PoW.
Or have I missed something!

PoW was also damaged and took water 400-600 tons. Leech reported 26-27kts best speed after the battle.

I have posted excerpts from PoW's log showing that she maintained an average of 28.4 knots and 231.8 RPM from 0600-0700.

[alecsandros2]

I'm speaking to the idea presented by RF about extending the engagement against POW via long range gunnery rather trying to run it down.

I don't see how or why the action woould become "long range", as the ships were at 13km distance, and probably had the same real speed at the time. Thus, if Bismarck would attempt a pursuit, the distance would not increase, but it would more or less stay the same for the duration of the pursuit, as long as the speeds would be nearly identical.

[alecsandros]

I have posted excerpts from PoW's log showing that she maintained an average of 28.4 knots and 231.8 RPM from 0600-0700.

Cpt Leech expressely reported best speed of 26kts. German speed estimate of PoW at the time was 25kts.

Shaft RPM does not directly translate to speed - only if the other variables are constant. But as it was, PoW suffered several underwater hits,and had several hundred tons of water in her.

[paul.mercer]

I'm speaking to the idea presented by RF about extending the engagement against POW via long range gunnery rather trying to run it down.

I don't see how or why the action woould become "long range", as the ships were at 13km distance, and probably had the same real speed at the time. Thus, if Bismarck would attempt a pursuit, the distance would not increase, but it would more or less stay the same for the duration of the pursuit, as long as the speeds would be nearly identical.

Thanks for your replies, but did Bismarck not reduce speed to effect repairs and therefore would have dropped back? If she had continued to persue PoW surely she would have put tremendous pressure on her bulkheads and made patching the repair almost impossible at that speed?
Also, Lutjens could not have known that PoW's aft turret was out of action at the time so as far as he was concerned it was 4X14" against 4x15" and the prospect of a long stern chase with the risk of sustaining further damage.

[alecsandros2]

I'm speaking to the idea presented by RF about extending the engagement against POW via long range gunnery rather trying to run it down.

I don't see how or why the action woould become "long range", as the ships were at 13km distance, and probably had the same real speed at the time. Thus, if Bismarck would attempt a pursuit, the distance would not increase, but it would more or less stay the same for the duration of the pursuit, as long as the speeds would be nearly identical.

Thanks for your replies, but did Bismarck not reduce speed to effect repairs and therefore would have dropped back? If she had continued to persue PoW surely she would have put tremendous pressure on her bulkheads and made patching the repair almost impossible at that speed?
Also, Lutjens could not have known that PoW's aft turret was out of action at the time so as far as he was concerned it was 4X14" against 4x15" and the prospect of a long stern chase with the risk of sustaining further damage.

Damage assesment was done on Bismarck only after the battle - at around 7:00. At 6:05 or so, nobody knew about the hit in the forecastle.
Thus, the ship continued to move at high speed for almost 1 hour before the damage was observed and speed was reduced to 22kts for damage repair to be conducted.

Gun flashes and fall of shot of enemy ships were continously observed, and it was quite clear that "King George" was withdrawing with "heavy damage", and the last salvos, fired by the Y turret, were scattered and only contained 2 shells [and a few minutes later, it stopped fireing alltogether, allthough the range was still not to big]

Moreover, speed of PoW was estimated as "25kts" after the battle, so given the information available to the Germans, they might have tried a short pursuit...

[RF]

I don't see how or why the action woould become "long range", as the ships were at 13km distance, and probably had the same real speed at the time. Thus, if Bismarck would attempt a pursuit, the distance would not increase, but it would more or less stay the same for the duration of the pursuit, as long as the speeds would be nearly identical.

It is likely that the distance would slowly increase if Bismarck chased after a retreating POW by following a tangential course to POW to allow turrets Ceasar and Dora to bear on the target for full salvo firing. The actual speeds of the ships would be similar, as other forum members have already posted.

[dunmunro]

I have posted excerpts from PoW's log showing that she maintained an average of 28.4 knots and 231.8 RPM from 0600-0700.

Cpt Leech expressely reported best speed of 26kts. German speed estimate of PoW at the time was 25kts.

Shaft RPM does not directly translate to speed - only if the other variables are constant. But as it was, PoW suffered several underwater hits,and had several hundred tons of water in her.

Shaft RPM doesn't translate to a specific speed if the ship's props have reduced efficiency, the displacement is higher than normal and/or the weather hinders the ship's speed but none of these conditions effected PoW. Here's the signals that Leach made to the Admiralty:

Naval Cypher (A) by T/F.

Addressed Admiralty, C. in C. Home Fleet.
XXXXXXXX. IMMEDIATE.
Following received from H.M.S. PRINCE OF WALES Addressed C.S. 1 begins.
A and B turrets in action. Y turret 2 guns in action. About 400 tons water in ship mainly abaft after bulkhead. Compartment above steering compartment flooded but steering gear in action. Estimated best speed 27 knots. T.O.O. 0720/24 Ends.

1007/24
SECRET MESSAGE IN
Received:-
From H.M.S. PRINCE OF WALES Date 24.5.41.
Time 1253

Addressed Admiralty C. in C. Home Fleet C.S.1.
IMMEDIATE.

Main armament control undamaged 9 main armament guns in action. Secondary armament guns in action Considerable damage to bridge. Both forward high angle directors out of action. About 60 tons water in ship mainly aft from 2 or more hits about water line. Estimated maximum speed 26 knots. Oil fuel made readily available 1600 tons.

http://www.hmshood.com/history/denmarks ... amage1.htm

As is usual in the RN, Leach did not state PoW's maximum speed, but her sustained maximum speed. PoW did not suffer enough flooding to slow her appreciably, especially as she had burned off nearly 2000 tons of oil by this time. PoW would have lost speed equivalent to the loss of one or at most two boilers, but this meant that she could still produce 100,000-117000 shp, and 117000shp would mean a speed of ~28.5 knots and 100,000 would mean roughly 27 knots. Her log entry for 0600-0700 still shows her making well over 112000shp.

Bismarck, OTOH, had suffered enough flooding forward that her props were losing efficiency, and with her bow buried deeply in the water she would also have increased water resistance. Bismarck was also suffering from direct flooding of machinery spaces, and she would probably have shut down the boiler room which was partially flooded.