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Improved Amphion
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Author:  Garlicdesign [ December 17th, 2016, 7:22 pm ]
Post subject:  Improved Amphion

Hello again!

Acting on info provided by Smurf, here's a design for an improved Amphion with three shafts - turbines on the flank shafts, diesels on the center - that was not followed through.
[ img ]

Greetings
GD

Author:  emperor_andreas [ December 17th, 2016, 8:19 pm ]
Post subject:  Re: Improved Amphion

Very nice work!

Author:  Novice [ December 17th, 2016, 9:15 pm ]
Post subject:  Re: Improved Amphion

An interesting concept, to say the least, as Britain seemed to have an aversion to the motor engine, even though the benefits of using them were apparent, especially for merchant ships.

Author:  Krakatoa [ December 17th, 2016, 11:26 pm ]
Post subject:  Re: Improved Amphion

Using diesels on what could have been used as patrol cruisers always made sense to me, and I could only wonder why navies did not use the combination for much greater range potential.

Author:  heuhen [ December 17th, 2016, 11:47 pm ]
Post subject:  Re: Improved Amphion

Nice drawing.


about engine:


Can it be because of that it was:
1. easier to get hold of people that can steam engine than Diesel engine. (There was still steam engine running the industry and everything else back then).
2. Countries had easier access to coal than diesel.
3. reliability concerns of diesel engine.
4. That it was something new and people was after the old school... submarine isn't a gentleman work.

Author:  smurf [ December 18th, 2016, 9:55 am ]
Post subject:  Re: Improved Amphion

I agree about using diesels generally. In this particular case there were design problems over structural strength and protection. The 6000 hp Vickers diesel was located in the aft engine room, with 12,000shp turbines remaining forward. However, the diesel was taller than the turbines, so the cylinder heads were above the armour and needed large access panels in the deck for maintenance. But Admiral Fisher (who was also keen to see battleships with diesels - he thought funnels might be dispensed with) retired as First Sea Lord in 1910, and his successor was not so keen on more innovations, and wanted the bigger Towns.
My thanks to Garlicdesign for a splendid rendering of this little-known design. Note the big central prop for the slow-running diesel.

Author:  Hood [ December 18th, 2016, 10:05 am ]
Post subject:  Re: Improved Amphion

Very nice work GD, an interesting addition too. Thanks go to smurf for commissioning this drawing too.

Author:  smurf [ December 18th, 2016, 10:50 am ]
Post subject:  Re: Improved Amphion

A small point. I suppose whether the design was an "improved" Amphion might be argued, but it was officially termed "New Amphion"

Author:  signal [ December 18th, 2016, 1:13 pm ]
Post subject:  Re: Improved Amphion

I'm not sure about the timing, but the Admiralty design committee pulled
an about face on petroleum for ship's fuel. After the Queen Elizabeth's, they
feared that it would be difficult or impossible to move oil from the Persian
Gulf to Britain in wartime (blockade/enemy cruisers/raiders, etc.). So they
changed the design of the R Class battleships to have them powered by coal.
Hence the R Class are built to different dimensions to accommodate the
coal bunkers and alternate power plant. This concept of diesel engines may
have met the same fate - a vote of no confidence in the availability of the fuel.

Author:  smurf [ December 18th, 2016, 4:41 pm ]
Post subject:  Re: Improved Amphion

Signal: you may be "not sure about the timing" but you may well be right, though diesel fuel and fuel oil for burning to raise steam are not the same.
'New Amphion reached the design submission stage (Specification and 1/16in scale drawing - which Garlicdesign didn't get, I've only got a paper copy of that drawing) in 1911. So work began under Fisher and stopped under Wilson as First Sea Lords
Conversely, the R's were designed for coal before Fisher's return in 1914, but then redesigned for oil.
Wiki: "First Sea Lord Jackie Fisher rescinded the decision for coal in October 1914. Still under construction, the ships were redesigned to employ oil-fired boilers that increased the power of the engines by 9,000 shp"
Note that though the 25knot Towns class cruisers designed from 1909 to 1912 were fired with coal (and oil sprayed on the coal for maximum power) the fast light cruisers of 1912 to 1914 design origin aiming for 30 knots (Arethusas and Carolines and then later 'C's) were all designed to burn oil to get the required power and speed. There was an evaluation of what it would take to get 'C' class performance with coal (and oil sprayed on the coal). It came out at around 6000tons instead of under 4000, with machinery weight 1300tons instead of 800, and twice the required weight of fuel.
'New Amphion' was designed for increased range, rather than increased speed. Total power was the same as Amphion - 18,000hp for 25 knots.

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