Electric-drive BB's - tactical use of astern?

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OpanaPointer
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Re: Electric-drive BB's - tactical use of astern?

Post by OpanaPointer » 31 Aug 2020 19:25

OldBill wrote:
31 Aug 2020 02:41
Wont they have to come to a full stop, then begin going astern? That makes a gunnery solution easier for the enemy doesn't it? Additionally this would seem to have plenty of potential to entirely disrupt the battleline.
Full stop is just one point on the arc. The ship's speed would be continuously changing, a bit of a challenge. As for the battleline, "distressed" ships are part of the practice.
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Re: Electric-drive BB's - tactical use of astern?

Post by TheMarcksPlan » 01 Sep 2020 23:53

paulrward wrote:
31 Aug 2020 19:18
Hello All;

Mr. TheMarcksPlan noted :
OTOH there were 6 e-BB's including the last five commissioned before WW2.
As these ships were the most powerful ships in the interwar US fleet.......
Actually, by the time W2 had broken out, it was down to five e-BBs - The New Mexico,
in her 1931-1933 major overhaul had her turboalternators and motors removed and
replaced with standard type geared turbines. As a result, during the Fleet Problems
of 1936, she showed a clean pair of heels to all the other battleships, exceeding 21 knots.

Respectfully :

Paul R. Ward
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Any stats for the weight of NM's generators and motors? And cost?
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Re: Electric-drive BB's - tactical use of astern?

Post by paulrward » 02 Sep 2020 01:14

Hello All :

Mr. TheMarcksPlan wrote :
Any stats for the weight of NM's generators and motors? And cost?

The total weight of the installed machinery plant on the three New Mexicos was about the same,
between 2300 and 2350 tons. ( Slight variations in boiler weights between manufacturers will
affect this. ) Which means that the New Mexico's turboalternators and motors weighed about
the same amount as the turbines and reduction gears of the Idaho and Mississippi.

The trials horsepower was also about the same, ranging from 32,000 ehp to 33,000 ehp / shp, and
giving speeds of about 21.0 to 21.3 knots for the three ships. ( Idaho was the fastest on trials, but
this would change from day to day.)

During the rebuild in the early 30s, the Idaho and Mississippi kept their engineering plant ( despite
what may be said on some websites ) though their turbines were rebuilt, as they were getting
worn out. However, on the New Mexico, an entirely new plant was installed, which, for the same
weight, produced over 40,000 shp. On her post refit trials, the New Mexico ran at between
22.0 and 23.0 knots, which is in keeping with a calculated top speed with 40 K ponies of 22.63
knots.

New Mexico spent a year in the Atlantic, and after her new machinery got sorted out, she went to
the Pacific. In the 1936 Fleet Problems, she repeatedly showed she was the fastest of the 'Old Line'
battleships, and was the pride of her division. This was one of the reasons why the three New Mexicos
were in the Atlantic Fleet on December 7th - They were tasked with guarding both the East Coast
and the Panama Canal on the Neutrality Patrols. With the loss of so many BBs at Pearl, they were
quickly transferred to the Pacific, and briefly served to provide convoy escorts and coastal protection
for the West Coast.

At one point, it was under consideration to move the Texas, New York, and Arkansas with them, along
with the North Carolina and Washington ( despite their propulsion defects ) and then, with the
return of the Pennsylvania, Tennessee, Colorado, and Maryland to service, the USN would have had
a rebuilt Battle Line of 12 dreadnoughts, capable of standing up to the IJN's gun fleet. Fortunately,
wiser heads prevailed, as it was now apparent that the age of the Battleship was fast ending, and
the Carriers were the new queens of the ocean.

I have been unable to find out a cost figure for the new machinery for the New Mexico, but have
a feeling it was sort of splitting the difference between the cost for the machinery on the Washington's
and one of the Baltimore's.

One has to ask, though : If the USN could have found the money to re-build their battle line in
the 1930s as the Japanese and the Italians did, replacing the twevle -14" guns on the Pennsylvanias,
the New Mexicos, and the Californias with eight 16" guns, and giving all of them new engines, the
USN would have had a fleet of ten 16" gunned dreadnoughts capable of over 22 knots of speed.

In effect, the USN would have had the most powerfull battle line in the world by 1939.

Hope this is of some help.

Respectfully :

Paul R. Ward
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