General Slocum propulsion

Dec 29, 2006
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Witney
I have just been looking at a TV programme about the loss of the General Slocum, and I am curious about the propulsion arrangements of this side-paddle vessel. In particular, what was the purpose of the curious metal structure that projected through the upper deck near the twin funnels - was this something to do with the valve gear?
 
May 3, 2005
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There are probably some of the experts who can give you a better answer.
But it looks like what I believe they called them a " walking beam " which was part of the engine which drove the side paddle wheels ?
 
Dec 29, 2006
729
5
88
Witney
I think a "walking beam" engine was a sort of beam engine, similar to those which had been used in mines since the 18th century. This seems a curiously-archaic method of propulsion for a ship built as late as the 1890s. (Thames river steamers such as those constructed by Messrs Salter Brothers of Oxford were usually equipped with triple expansion engines).
 
Dec 4, 2000
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Walking beam engines were used primarily on sidewheel vessels such as river steamers. They were also popular on day excursion boats, again sidewheelers. If you think about it, the reason is obvious -- the need to turn the paddle crank shaft at right angles to the keel. Typically, the cylinder or cylinders of this type of engine worked up-and-down rocking he beam far overhead, often over top of the superstructure roof. In teeter-totter fashion as the engine end of the beam was pushed up, the end driving the paddle crank was pushed down. A simple crankshaft arrangement transferred this rocking into rotational motion to drive the paddle wheels.

Another engine that produced transverse rotation simply connected the push rod to the paddle crank. Cylinders of this type of prime mover were usually layed on their side, producing a V-shaped engine far in advance of the automotive designs. I've ridden one steamer of this configuration in which the cylinder actually "rocked" as it turned the crank. As this was nearly 70 years ago, I don't recall how steam was fed into the contraption. All I recall is that big push rod moving the crank overhead. In those years you could wander into the engine room to take a peek.

Paddle steamers had a decided advantage of shallow draft for working rivers. They were also popular on day excursion boats and coastal steamers. However, they were less efficient than the propeller steamers which eventually took over these routes. The in-line cylinders of a triple expansion marine engine produced rotational power along the keel, so no rocking beam was needed. The in-line engine simply rotates the tail shaft to which the propeller is attached.

Sidewheelers allowed one other overlooked advantage. The wheels on passenger boats were encased in sponsons extending from their main decks, Necessary rooms could be tucked into the triangular compartments abaft the wheels. Flushing for sanitation came from the splashing water thrown up by the wheels. No complicated or expensive plumbing necessary.

-- David G. Brown
 
Dec 27, 2017
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Isle of Man
Walking beam engines were used primarily on sidewheel vessels such as river steamers. They were also popular on day excursion boats, again sidewheelers. If you think about it, the reason is obvious -- the need to turn the paddle crank shaft at right angles to the keel. Typically, the cylinder or cylinders of this type of engine worked up-and-down rocking he beam far overhead, often over top of the superstructure roof. In teeter-totter fashion as the engine end of the beam was pushed up, the end driving the paddle crank was pushed down. A simple crankshaft arrangement transferred this rocking into rotational motion to drive the paddle wheels.

Another engine that produced transverse rotation simply connected the push rod to the paddle crank. Cylinders of this type of prime mover were usually layed on their side, producing a V-shaped engine far in advance of the automotive designs. I've ridden one steamer of this configuration in which the cylinder actually "rocked" as it turned the crank. As this was nearly 70 years ago, I don't recall how steam was fed into the contraption. All I recall is that big push rod moving the crank overhead. In those years you could wander into the engine room to take a peek.

Paddle steamers had a decided advantage of shallow draft for working rivers. They were also popular on day excursion boats and coastal steamers. However, they were less efficient than the propeller steamers which eventually took over these routes. The in-line cylinders of a triple expansion marine engine produced rotational power along the keel, so no rocking beam was needed. The in-line engine simply rotates the tail shaft to which the propeller is attached.

Sidewheelers allowed one other overlooked advantage. The wheels on passenger boats were encased in sponsons extending from their main decks, Necessary rooms could be tucked into the triangular compartments abaft the wheels. Flushing for sanitation came from the splashing water thrown up by the wheels. No complicated or expensive plumbing necessary.

-- David G. Brown
Those sidewheelers with rocking cylinders received their steam and exhaust through the shaft on which they rotated using Corliss valves. Not terribly efficient but a simple solution to the problem.
 
Dec 4, 2000
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The Corliss valve may not have been the most efficient, but I'm sure the crew preferred it to sweep oars and a big drum.

-- David G. Brown
 
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