Date: Sun, 4 Sep 2005 10:19:10 -0400
Reply-To: Don in North Carolina <vanagondon@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Don in North Carolina <vanagondon@GMAIL.COM>
Subject: Re: Gas time line: nuclear nonsense
In-Reply-To: <000c01c5b10e$8284ffe0$657ba8c0@MAIN>
Content-Type: text/plain; charset=ISO-8859-1
On 9/4/05, Robert Fisher <refisher@mchsi.com> wrote:
<SNIP>
> The experience at Pearl Harbor also weighed heavily into the Navy's desire
> to have a solution for capital ships that would provide short start-up times
> and would not leave them possibly fuel starved. If the fleet had been warned
> of the approach of the Japanese at the earliest reasonable time based on the
> technology of the time, they would have had about seven hours. It takes
> longer than that to reliably fire up a boiler propulsion system, and most of
> the battleships were very low on fuel to begin with. As an aside, most of
> the modern ships have gas turbine engines, which, while they still run on
> fuel (jet fuel), they can be fired up and ready in about thirty minutes.
<SNIP>
> Cya,
> Robert
> (also no expert on the issue)
Robert,
Cool, something I have some experience with (gas turbines). The gas
turbine powered ships were built in response to Pearl Harbor. A gas
turbine ship, such as the DD-963 (Spruance) class destroyers, can go
from cold iron to answering a Flank 3 bell in LESS than 3 minutes.
During the acceptance trials, the USS Spruance had all of it's engines
started and shaft turning in less than 2 minutes - unfortunately, they
were not as quick cutting the mooring lines
and the ship got underway with two lines still attached. One line
separated, the other ripped the bollard out of the pier - the ship
want to go!
The Spruance class were designed to run on jet fuel (JP-5), it's true,
but to cut costs the engines main fuel controls have been re-indexed
to run DFM (Diesel Fuel Marine), the same fuel as any diesel ship
(both cheaper and more readily available). The only current use of
JP-5 on the gas turbine powered ships is for their helicopters.
Just as a side note, the gas turbine powered ships use a controllable
reversible pitch propeller, as the engines cannot be reversed. The
blades of the propeller move and reverse their pitch, giving the ship
the capability to back up. The in spec time to go from a Flank 3 bell
to Back Full is 90 seconds, though most do it in under 50 seconds.
The Spruance class is also one of the few ships that does not require
tug services to tie up to a pier, as the fast response time (the
throttles are directly controlled from the Bridge) and it's ability to
"walk" into the pier make tugs unnecessary.
--
Don in Reidsville, NC
Former Gas Turbine System Technician, US Navy
1986 Kawasaki Concours
1988 Vanagon GL (Sylvia)
"I reject your reality and substitute my own." - Adam Savage
|