Naval History Forums

Gentlemen,
The QE class battleships were designed to have a top speed of around 24-25 knots, the Royal Sovereign class, which came later were around 23 knots as were the Nelsons, even the N3 was only going to do about 23.5 Knots, in fact the only ones with any speed were the KGv's and they were still slower than most of their rivals.
My question is why so slow? all the equivalent ships of the French, Germans, Italians, US and Japanese were so much faster, did the British designers still live in the first world war and think that nothing better was required?

No battleships that were conteporaries of the QEs were faster, as to the KGVs..........two classes of US "Fast" battleships were pretty much on par with them, as were the Yamatos leaving just the German , French and Italian ships that were indeed faster......oh and the Iowas also.

The QEs were fast for the time they were designed and built. Almost as fast as period battle cruisers. That's another thing; the RN built battle cruisers during that time frame.

KGV's were not all that slow. They were faster than the North Carolinas and South Dakotas, or Yamato, and almost as fast as Bismarck.

Vanguard could do 30 knots.

There was another factor. The British were quite conservative about employing the new high-temperature, high-pressure propulsion systems. This made it more difficult for them to achieve more power without making the power plant prohibitively large.

Keith Enge wrote:There was another factor. The British were quite conservative about employing the new high-temperature, high-pressure propulsion systems. This made it more difficult for them to achieve more power without making the power plant prohibitively large.

This is complete nonsense. The KGV class had a superior power to weight ratio to any of their immediate contemporaries except SoDak. The French, Italians and IJN employed lower temperatures and pressures than the RN. The first generations of USN and KM HP machinery did not achieve either a size or weight advantage over the KGVs. Washington only appears to have a size advantage because the USN deleted almost all internal subdivision within the machinery spaces.

The RN were quite conservative in rating the output of their power plants and this has tended to obscure their actual power to weight ratios. PoW, for example achieved 134000shp in service and had lighter machinery than Washington, with higher output:

KGV / Washington
Weight Equipment (tons) 1150 / 1200
Weight Machinery (tons) 2770 / 2900
nominal Power output 110,000 / 121000
Max Power output 134000+* /127000**

Friedman, US BBs, p278
*G&D, Allied BBs, p191
**Friedman p275.

dunmunro wrote:PoW, for example achieved 134000shp in service

you keep repeating this all over the place as if it was law because G&D worte: "...main machinery steamed at overload powers of 128,000 to 134,000 shaft horsepower with no difficulties..."
ok, thats fine they are great authors and researchers, but what is their source. are the original machinery reports available?

Pandora wrote:

dunmunro wrote:PoW, for example achieved 134000shp in service

you keep repeating this all over the place as if it was law because G&D worte: "...main machinery steamed at overload powers of 128,000 to 134,000 shaft horsepower with no difficulties..."
ok, thats fine they are great authors and researchers, but what is their source. are the original machinery reports available?

Yes, in the UK archives, as is the log entries with shaft RPM and speeds, which I have posted here as well.

dunmunro wrote:

Yes, in the UK archives, as is the log entries with shaft RPM and speeds, which I have posted here as well.

That would imply the machinery to work at 34% overload, which I find difficult to believe, given the temperatures adn pressures involved. Also, I don't see a ship doing 28.5kts@110.000hp and only 29kts @134.000hp.

Until I see some original documents supporting G&D's lacunar report, I am skeptical about it.

alecsandros wrote:

dunmunro wrote:

Yes, in the UK archives, as is the log entries with shaft RPM and speeds, which I have posted here as well.

That would imply the machinery to work at 34% overload, which I find difficult to believe, given the temperatures adn pressures involved. Also, I don't see a ship doing 28.5kts@110.000hp and only 29kts @134.000hp.

Until I see some original documents supporting G&D's lacunar report, I am skeptical about it.

How did you calculate 34%? PoW ran trials at 11.6k shp at 28 knots @42.1k tons . The power curve will rise steeply as the speed increases, so another 22k shp to gain 1.1 knots is about right. The log entries confirm the data from G&D.

Bismarck's nominal power rating was 118K shp, but it achieved considerably more.

dunmunro wrote:

Pandora wrote:

dunmunro wrote:PoW, for example achieved 134000shp in service

you keep repeating this all over the place as if it was law because G&D worte: "...main machinery steamed at overload powers of 128,000 to 134,000 shaft horsepower with no difficulties..."
ok, thats fine they are great authors and researchers, but what is their source. are the original machinery reports available?

Yes, in the UK archives, as is the log entries with shaft RPM and speeds, which I have posted here as well.

Does it mention 134,000 shaft horsepower?
I dont think G&D had access to that report when they wrote their book 20 years ago.

Pandora wrote:
Does it mention 134,000 shaft horsepower?
I dont think G&D had access to that report when they wrote their book 20 years ago.

Ga&D state that their info comes from Captain Leach's action reports. They list a number of admiralty documents amongst their source material.

The log entries state time, shaft RPM and speed.

dunmunro wrote:Ga&D state that their info comes from Captain Leach's action reports. They list a number of admiralty documents amongst their source material.

I see. any idea which document gives 134,000 shaft horsepower so we try and check?

The log entries state time, shaft RPM and speed.

what about shaft horsepower?

Pandora wrote:

dunmunro wrote:Ga&D state that their info comes from Captain Leach's action reports. They list a number of admiralty documents amongst their source material.

I see. any idea which document gives 134,000 shaft horsepower so we try and check?

The log entries state time, shaft RPM and speed.

what about shaft horsepower?

from G&D:

Unpublished Material
Royal Navy, Ministry of Defence. Design History-King George V Class.
Royal Navy, Ministry of Defence. Design History-HMS Vanguard.
Royal Navy, Ministry of Defence. HMS Prince of Wales -Shell Damage, DNC4 BR-69.
Royal Navy, Admiralty and Secretariat. Cases IADM 116/4521 ,4554).
Royal Navy, Ministry of Defence'. Official Ship Cover-Lion Class Battleships, 1938-1942
(Curator No. 577, 577A, 577B).
Royal Navy, Admiralty. War of 1939·1945-War History: Cases and Papers (ADM 199/1149).
Royal Navy, Diving Survey-HMS Prince of Wales, 23 May 1966, 811 FEF 169/8 Ops.
Royal Navy. "Records of Naval Construction during the War 1939-1945."
Royal Navy. "Naval Staff History on the Loss of the Prince of Wales and Repulse," (BR
173618)155)

I would start with ADM 199/1149.

Given displacement and shaft RPM and speed, the SHP is implied, but this is not a standard log entry. However, it would be known by the engineering staff, as in any warship, given these variables.

ok thanks.

dunmunro wrote:
How did you calculate 34%? PoW ran trials at 11.6k shp at 28 knots @42.1k tons . The power curve will rise steeply as the speed increases, so another 22k shp to gain 1.1 knots is about right. The log entries confirm the data from G&D.

Bismarck's nominal power rating was 118K shp, but it achieved considerably more.

Well, I'm thinking about KGV class normal power output, which was 100.000hp. The maximum power was 110.000 hp (at least the design specs). So achieving 134000hp would be 34% above the normal, and 21.8% above the maximum. The Bismarck maximum output was 138000hp, with an overload of 9.2%, up to 150700hp...

I remember a KGV speed trial @41000t, at around 113000hp, and 28.5kts. I may be wrong though...