Re: Coal to Oil Conversion of Naval Vessels
- From: azb@xxxxxxxxxx (Andrew Robert Breen)
- Date: Mon, 3 Dec 2007 19:19:59 +0000 (UTC)
In article <fj1dfp$1n1$1@xxxxxxxxxxxxxxxxxxxx>,
R.C. Payne <rcp27@xxxxxxxxxxxx> wrote:
Richard Casady wrote:
On Mon, 03 Dec 2007 15:17:56 +0000, "R.C. Payne" <rcp27@xxxxxxxxxxxx>
wrote:
The size and weight of the engine for a given power and the very
impulsive way it delivers work are two things that spring to mind. And
of course the coal barge.
The first use was pumping water from coal mines. Since the coal in the
mine was otherwise unobtainable, the fuel consumption didn't really
matter.
Sure, they were fine for the job they were invented for: pumping water
from mines. While the engine could cause a weight to rise and fall at a
pit-head, to drive a pump, I don't see how technology of the first half
of the 18th century could usefully convert that to propulsion for a ship
(could they make an appropriate connecting rod and crank at that
point?[1]). So you have a large and heavy engine, a whole load of coal
Stanhope's designs for reciprocating paddles - used on the
_Ambi-Navigator_ pre-dated Watt's patent for rotatitive engines (and so
were intended to work with a linear engine) so a crank (or a Sun/Planet gear,
which is what Watt used) isn't a requirement. Actually, I can think of a
couple of other ways to drive a rotary machine from a linear engine (rack
gears, as used in Burstall's 1820s steam coaches being one), o being able
to make an adequate crankshaft isn't a make-or-break issue.
and a crew to run the engine. This engine isn't going to produce enough
power, bearing in mind that the machinery to provide thrust is likely to
be equally crude, I just can't see it topping a knot or two in still
water. An interesting curiosity, but not useful for anthing.
/Bloody/ useful in a flat calm. A "knot or two" was pretty much what oared
gunboats made, and they were damned dangerous in a calm. Useful for
getting in and out of harbour, too. If it makes the difference between
getting out and seeing something go sailing past, unengaged..
[1] One of the big steps forward was when Watt produced a rotating
engine, which presumably would have been done earlier if it could have
been, which leads me to suspect that without Watt parallel motion and a
double acting piston it's just not going to work.
Watt's first rotatitive engines were single-acting, IIRC, so that's not a
requirement. Parallel motion of some kind is useful, but there were
several species nder development at the time. And (as above), you don't
need a rotatitive engine to drive a ship. It helps, that's all.
The big issues were weight, power and fuel consumption. A Newcomen engine
big enough to be useful was simply too heavy for a small ship. The coal
requirements made it worse. It took the steady refinement of engines
(driven largely by the use of steam engines in metal mines, distant from
the sources of coal, plus the expiry of some of thw Watt patents) though
to the 1820s to produce engines capable of driving a seagoing ship. Mind,
this was largely because early steamships were very much full-power steam.
Develop a workable propellor and shaft-joint earlier and Newcomen or Watt
engines might have put steam in ships earlier - it's much easier to build
a low-power auxiliary steamship with a screw than paddles..
--
Andy Breen ~ Not speaking on behalf of the University of Wales, Aberystwyth
Feng Shui: an ancient oriental art for extracting
money from the gullible (Martin Sinclair)
.
- References:
- Re: Coal to Oil Conversion of Naval Vessels
- From: R.C. Payne
- Re: Coal to Oil Conversion of Naval Vessels
- From: Richard Casady
- Re: Coal to Oil Conversion of Naval Vessels
- From: R.C. Payne
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