Was the battleship Bismarck really the best of its time?

[hans zurbriggen]

Hello Mr. Wahl,
thanks indeed.
Assuming models prior to C/35 were not able to take into account radar measures, do you know whether FC equipment was upgraded when "old" ships got radars and even very performing gunnery radars like FuMO 26 ?

hans

[fsimon]

Hallo Thorsten,
what is a target disposer? Can you kindly explain that, please? I appologize for my amateurisch ignorance.

Frank

[Thorsten Wahl]

My fault. Bad translation from german.

Target indicator should be better wording.

Optical instrument for measuring azimuth position of the target.

[fsimon]

Thank you

[hans zurbriggen]

Hello Mr. Wahl,
I had wrongly written ' Bismarck equivalent thickness is decreasing with increased shell descent angle (20° decent angle would give 520 mm 'only' ...' but you wrote that with 320 mm + 120 mm + 45 mm and AOF 20, LOS would be reduced 'just' to 568 mm (please see here http://www.kbismarck.org/forum/viewtopi ... 830#p89830 ).

Possibly my mistake, but looking again at it IMHO LOS = 320 / cos(20°) + 120 / sin (42°) + 45 / cos (20°) (disregarding all trajectory changes) = 568 mm , therefore a loss of LOS around 17%. Is this new calculation correct ?

I however agree with you that shell speed loss + de-capping + jawing would more than compensate for LOS loss.

hans

[Thorsten Wahl]

Is this new calculation correct ?

Yes.

[fsimon]

Herr Nilsson, Do I understand this correct?
TS1 transmitter tube 2kw
TS6 transmitter tube 8kw.
Both could be used with 500Hz PRF or 2000Hz PRF units.
"Peilung fein" module could be used with either TS1 or TS6 and both 2000 Hz PRF or 500 Hz PRF.
Bismarck used 2000 PRF on all its Seetakt.
"Entfernung fein" could be used on all Seetakt radar and was used on all Bismarck's Seetakt.
2000 Hz PRF restricted maximum unambiguous ranging to 75km i.e. vs aircraft.
Bismarck had the module "Peilung fein" on only one of its Seetakt, the foretop mounted Seetakt.
TS1 transmitter tube power limited maximum tracking to 25km versus battleship sized targets.
Peilung fein was not used to determin designation FuMo 23 vs. Fumo 27.
Was the TS6 tube used to determine the designation FuMo 27?
Or was the use of 500 Hz PRF vs 2000 Hz PRF used to determine the designation FuMo 27?
Or did the use of different antennas or antenna sizes determine the designation FuMo 23 / FuMo 27

Does anybody know, if Mr Dave Saxton has published his book on WW2 naval radars?

Best regards
Frank

[Thorsten Wahl]

Seems not.

[Herr Nilsson]

Herr Nilsson, Do I understand this correct?
TS1 transmitter tube 2kw
TS6 transmitter tube 8kw.
Both could be used with 500Hz PRF or 2000Hz PRF units.
"Peilung fein" module could be used with either TS1 or TS6 and both 2000 Hz PRF or 500 Hz PRF.
Bismarck used 2000 PRF on all its Seetakt.
"Entfernung fein" could be used on all Seetakt radar and was used on all Bismarck's Seetakt.
2000 Hz PRF restricted maximum unambiguous ranging to 75km i.e. vs aircraft.
Bismarck had the module "Peilung fein" on only one of its Seetakt, the foretop mounted Seetakt.
TS1 transmitter tube power limited maximum tracking to 25km versus battleship sized targets.
Peilung fein was not used to determin designation FuMo 23 vs. Fumo 27.

IIRC, yes

Was the TS6 tube used to determine the designation FuMo 27?
Or was the use of 500 Hz PRF vs 2000 Hz PRF used to determine the designation FuMo 27?
Or did the use of different antennas or antenna sizes determine the designation FuMo 23 / FuMo 27

No
Yes
No


Prinz Eugen had a TS6 transmitter tube (foretop) and a TS1 transmitter tube (rear) during "Rheinübung" both 2000 Hz PRF. She had severe problems with the detuned foretop-"Messekette" (600-800 m difference to optical range taking). The measurement error could be reduced to 200-300 m. The highest ranges were for Hood and PoW 220 hm and 376 hm for a Sunderland seaplane.

[fsimon]

Thank you very much Herr Nilson!

I appreciate your answer and taking the time.

May I ask you and also Thoddy for an opinion on the parameters for the Seetakt radars that I found in differnt discussions?

FuMG 39 as installed on Bismarck:
Antenna 2 x 4m
The foretop installation including Peilung fein and Meßkette for artillery.
This installation would then use lobe switching.
Angular accuracy: 0.1°I have not seen this number in any document only in discussions here.
Angular resolution 3° (i.e. the 3db or 50% beam width)
Range accuracy: 38m
Range resolution would be the half pulse length, but I have learned from you Thoddy, that the triangular A-scope presentation allowed to differentiate the tips of much closer returns i.e. resolve impact splashes down to 10m intervals.
I would be greatful to read your opinions.
Best regards
Frank

[fsimon]

The 220hm of Prinz Eugen on PoW and Hood give me the impression that Peilung fein was used otherwise I would expect a greater range.