HMS Howe speed

Propulsion systems, machinery, turbines, boilers, propellers, fuel consumption, etc.
paul.mercer
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Re: HMS Howe speed

Postby paul.mercer » Fri Feb 10, 2012 9:29 pm

Gentlemen,
I presume that even if a ship is designed to do 29 knots whether it actually achieves or exceeds that speed is entirely due to what happens on that particular day, given the effect of weather, engine room conditions, fuel etc. I believe there are cases of ships exceeding their designed speeds. I suppose that in many ways it is no different to us humans, somedays we perform better than others!

dunmunro
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Re: HMS Howe speed

Postby dunmunro » Fri Nov 16, 2012 11:16 pm

DoY full power trials:

1 November 1941.

42,970 tons, Sea slight, wind moderate.

28,720 SHP at 153 RPM = 20.6 knots (full power on cruising turbines).
111,200 SHP at 232 RPM = 28.6 knots

From RA Burt, British Battleships 1919-1945, p402.

alecsandros
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Re: HMS Howe speed

Postby alecsandros » Mon Jan 28, 2013 9:10 am

Duncan,

I read somewhere that Prince of Wales obtained ~ 30kts during a run in the Mediteranean, 1941.

Do you have any more info on this ?

dunmunro
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Re: HMS Howe speed

Postby dunmunro » Mon Jan 28, 2013 5:07 pm

alecsandros wrote:Duncan,

I read somewhere that Prince of Wales obtained ~ 30kts during a run in the Mediteranean, 1941.

Do you have any more info on this ?



Battleship by Middlebrook and Mahoney, p40 states that PoW made 31.5 knots while trying to intercept the Italian fleet during Operation Halberd. I would prefer to see PoW's log before accepting this as fact.

alecsandros
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Re: HMS Howe speed

Postby alecsandros » Mon Jan 28, 2013 5:54 pm

dunmunro wrote:
alecsandros wrote:Duncan,

I read somewhere that Prince of Wales obtained ~ 30kts during a run in the Mediteranean, 1941.

Do you have any more info on this ?



Battleship by Middlebrook and Mahoney, p40 states that PoW made 31.5 knots while trying to intercept the Italian fleet during Operation Halberd. I would prefer to see PoW's log before accepting this as fact.

That would be great to see...

After all, how sure can we be about the maximum speeds of battleships ?

There can be differences of quite a few knots between the maximum speeds of the same ship just under different circumstances....

And in this line of thought, I was thinking the other day about sea currents.

I don't know how stupid this sounds to you, but I don't know how to put it any other way:

would a 3kts sea current add 3kts speed to a ship traveling inside it, presuming ship's course to be directly in line with the current ... ? Is this possible ?

dunmunro
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Re: HMS Howe speed

Postby dunmunro » Mon Jan 28, 2013 6:01 pm

alecsandros wrote:
dunmunro wrote:
alecsandros wrote:Duncan,

I read somewhere that Prince of Wales obtained ~ 30kts during a run in the Mediteranean, 1941.

Do you have any more info on this ?



Battleship by Middlebrook and Mahoney, p40 states that PoW made 31.5 knots while trying to intercept the Italian fleet during Operation Halberd. I would prefer to see PoW's log before accepting this as fact.

That would be great to see...

After all, how sure can we be about the maximum speeds of battleships ?

There can be differences of quite a few knots between the maximum speeds of the same ship just under different circumstances....

And in this line of thought, I was thinking the other day about sea currents.

I don't know how stupid this sounds to you, but I don't know how to put it any other way:

would a 3kts sea current add 3kts speed to a ship traveling inside it, presuming ship's course to be directly in line with the current ... ? Is this possible ?



Yes, it would add three knots to the ship's speed, but only the navigator would know that. The engineers would still be reporting the ship's speed via shaft rpm and pitometer which gives the ship's speed in relative terms and the navigator would then add the water current vector to calculate the actual distance that the ship had travelled.

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Re: HMS Howe speed

Postby alecsandros » Mon Jan 28, 2013 6:06 pm

dunmunro wrote:Yes, it would add three knots to the ship's speed, but only the navigator would know that. The engineers would still be reporting the ship's speed via shaft rpm and pitometer which gives the ship's speed in relative terms and the navigator would then add the water current vector to calculate the actual distance that the ship had travelled.


which info is usualy written in the log ?
pitometer speed or speed based on the actual distance traveled ?

dunmunro
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Re: HMS Howe speed

Postby dunmunro » Mon Jan 28, 2013 8:06 pm

alecsandros wrote:
dunmunro wrote:Yes, it would add three knots to the ship's speed, but only the navigator would know that. The engineers would still be reporting the ship's speed via shaft rpm and pitometer which gives the ship's speed in relative terms and the navigator would then add the water current vector to calculate the actual distance that the ship had travelled.


which info is usualy written in the log ?
pitometer speed or speed based on the actual distance traveled ?



All of it. The RN would report pitometer and average Shaft RPM and the navigator would then calculate the ship's position and distance covered.

paul.mercer
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Re: HMS Howe speed

Postby paul.mercer » Thu May 02, 2013 10:02 pm

alecsandros wrote:
dunmunro wrote:
PoW's log also recorded speeds of 29.1 knots just prior to intercepting Bismarck, and I have posted the excepts on this board.

We know about that Duncan.

But what about Howe's 29.5 ?


Whether 29.1 or 29.5 was achieved would surely depend on the conditions at that particular point in time, not only in the sea but on the ship, after all, the difference is so minimal it scarcely matters. I believe that steam powered engines can often exceed their maximum rating as opposed to diesel power which cannot.


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