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Sailing Ships. The speed of sailing ships can be improved by a variety of up-time improvements, which include the combination of square-rigged sails with fore-and-aft sails (1725), the round-headed rudder (1779), the steering wheel (1706), copper sheathing (1778), high length-to-beam ratios (1812), iron hulls (1838), and so forth. These advances led, directly or indirectly, to faster long-distance speeds. "In 1853 McKay's Sovereign of the Sea [an extreme clipper, with a long streamlined hull and plenty of canvas] sailed 421 miles in 24 hours." (Marshall, 99, 112, 114, 140 et seq., 152).
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Steamers. Steamships entered the river trade in 1807 and the ocean trade in 1819, but the paddles of the early models were less effective, and vulnerable to damage, in rough waters. Screw-propelled steamers first went to sea in 1839. Iron hulls, although first used on sailing ships, were even more important for the success of steamships, because they could better withstand the vibrations imparted by the propeller, and allowed construction of longer hulls, which in turn ensured ample space for the bunker, boiler and engine. (Marshall, 163-64) The combination of the iron hull and the screw propeller was first realized in Brunel's 1840 Great Britain. Later advances included steel hulls, high-pressure boilers, compound steam engines, and, after 1900, diesel engines.
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Air Travel. While there were pre-war experiments, use of aircraft to carry passengers, mail and freight escalated after World War I. Aircraft include airships (blimps and zeppelins), helicopters and planes. Before 1939, all planes had propellers driven by an internal combustion piston engine.
It is likely that the first post-RoF civilian aircraft will be using scavenged automobile engines. It will be some years before the USE can build new engines, with alternative designs, from scratch.
Aircraft designers must strike a balance between lightness and strength. The first aircraft were wood-and-canvas constructions, but steel was used in the Fokker DVII, and aluminum alloys came into common use between the two world wars.
Because there are no airports yet, there is going to be a lot of interest in bush planes with floats, skis or outsize "tundra tires."
Larger aircraft may be seaplanes or amphibious aircraft, and their water landing capability may be attributable to floats or to buoyant hulls ("flying boats"). The first transoceanic passenger flights used such notable examples as the Sikorsky S-38 (1928), the Martin M-130 (1934), the Sikorski S-42 (1936), and the Boeing 314 (1938). These planes had formidable engines.
Uptime Improvements in Intermodal Transfer
In the seventeenth century, goods might be floated downriver on rafts or barges, loaded onto a sailing ship, and transferred at the destination port to a wagon to be hauled to the final destination. Each time there was a change of transportation mode, the various sacks and crates would have to be taken off one vehicle, and then stowed on another. This cost time and money.
Consequently, there have been several methods over the years to improve the efficiency of intermodal transfers.
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Road/Rail. Both up-time cars and down-time wagons can be transported by train, on some kind of flat car, to a trailhead, where they are offloaded and proceed further on their own. This is called "piggyback service."
In the early days of railroading, inventors tried to develop vehicles which could travel on both roads and rails. One pre-1850 rail-road vehicle offered what you might call an early example of the container concept. The stagecoach cabin was hoisted off a underframe bearing wagon wheels, and lowered onto another one with flanged rail wheels. (NOCK/D, plates 64–5, and page 128).
The modern equivalent is called a "swap body." It has a strong bottom section which can be placed on either a truck chassis or a rail bogie. It differs from a true contained in that the upper section is weak, so it can't be stacked.
One obvious problem with this design is the time lost in changing transportation modes. For track maintenance, various road/rail utility vehicles (e.g., pickup trucks) have been equipped with fore-and-aft sets of flanged guide wheels so they can literally stay on track. These were first commercialized in the 1940's, under the trademark HY-RAIL®, and largely replaced the old dedicated railcars. (Winkworth). However, the vehicles still ride on their tires.
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Land/Water. Vehicle ferries offer another form of "piggyback service." An adaptation of this was proposed; the "trailer ship," in which a truck trailer is detached from the "tractor" and rolled into the ship's hold.
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Containerization. The most important concept in intermodal transport is containerization. The cargo is shipped in large standardized, stackable containers (e.g., 20 x 8 x 6 feet) which are not opened in transit. A container may first move overland on a truck chassis, then be lifted onto a flat bed rail car, and travel by rail to a port where it's hoisted onto a "container ship."
Containerization reduces handling costs and time by a tremendous margin. Of course, the cranes and other handling equipment have to be of a scale and power suitable to the large, heavy loads presented by the containers.
The Effect of Uptime Improvements on Transport Costs
Improved Roads. Improved roads will affect transport costs in a variety of ways, direct and indirect. First of all, if a toll is charged for using a road, that naturally will increase costs. On the other hand, the improved road can be traversed more rapidly, which will reduce what must be spent for food and lodging for man and beast. Vehicle maintenance costs are also likely to be lower. In 1839, an engineer estimated that it cost 15-20 cents per ton-mile to transport goods on an ordinary turnpike, and only 10–15 cents on a macadam road. (Meyer 574). The turnpike, of course, was itself an improvement on the typical country road.
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New Vehicles. In theory, the same methods used to forecast costs for transport by packhorse, wagon, animal-drawn barge or sailing ship can be used to calculate the costs of using steamships, railroads, or even aircraft. That is, determine a characteristic ton mile cost for each mode, and then for any proposed shipment, multiply the ton mile unit cost by the cargo weight in tons and the route length in miles.
Such a calculation is straightforward, and, indeed the cost database, from which the ton mile rates are derived, is much more comprehensive for these nineteenth- and twentieth-century conveyances than for the down-time vehicles. The catch is that the rates are initially expressed in nineteenth- or twentieth-century dollars, or pounds sterling. My conversion methods are summarized in Table 2.
There are many objections which can be raised against relying on price indexes for rescaling transport costs from the nineteenth or twentieth centuries to the 1632 Universe. I discuss some of them in the Transportation System Addendum. But until someone comes up with a better alternative. rely on them I shall.
Returning to my earlier example, if a steam power-based railroad were operating between Eisenach and Hanover, I would predict (subject to the caveats about purchasing power) that the costs would drop to New US$6.90 per sewing machine case. And the transit time would be perhaps six hours.
Conclusion
The ideal goods for long-distance foreign trade are those which can be purchased cheaply, and yet have, at the intended destination, a high value relative to their weight and bulk. In the Age of Exploration, many voyages were made to search for new goods which could be the object of profitable trades (e.g., silver from the New World for silk from China).
One advantage that the up-timers have is that they know which goods were ultimately successful in the original time-line, and roughly where to find (or how to make) them. However, they cannot afford to ignore the economic realities of trading in the early seventeenth century. Those realities include an understanding of the costs of transportation.
References
References appear in the Transportation System Addendum on www.1632.org .
Steam: Taming the Demon
Written by Kevin H. Evans
DISCLAIMER
This articl
e is not intended to provide all the information needed to design and build actual boilers. Many skills and cross checks are needed to ensure the safe design and construction of pressure vessels. This article is to promote the understanding of steam technology, and to provide a useful framework for writing stories set in the 1632 verse.
Steam can REALLY KILL YOU
Steam Safety
Of all the substances on earth, water seems to be the most adaptable to transferring power from heat to work. When heated water boils and creates steam, the volume of water increases some 745 times (more according to some sources). This can power a simple engine capable of performing useful work with a relatively small fuel use. However, steam has its dangers. Steam will kill you if you give it the slightest chance. There are numerous things that must be done right every time. When water is enclosed and heated, it stores energy in the water. Steam will form in the "bubble" at the top of the enclosure, and pressure will increase. As the steam pressure goes up, the amount of heat required to create additional pressure increases. Also, more energy is stored in the water. As the pressure is released the "superheated" water changes to steam. If the pressure is released all at once, all the water will become steam at once. Thus 100 gallons of water becomes at least 9,950 cubic feet of steam. Most standard boilers carry from 500 to 1,000 gallons of water. That would give us 49,750 to 99,500 cubic feet of steam.
In a locomotive, this sudden expansion normally separates the boiler from the frame and has been known to throw the boiler hundreds of feet from the wreck site. Needless to say, the engineer and fireman are almost always scalded to death, and the steam cloud can drift over the train and kill every one else on board.
Steam has several hazards. First there is thermal damage. This is heat energy contained in the steam transferring to a victim. Then there is the shock wave caused by the sudden expansion of the superheated water to steam. This can cause damage similar to a chemical explosion, with shrapnel and damage to persons and structures. The cloud of steam can spread and cause further thermal damage. In addition, the steam cloud is denser than air and hugs low spots and fills spaces like rooms and compartments This cloud also excludes oxygen and will cause death from suffocation even if the cloud is cool. Lastly, a steam leak from an otherwise intact boiler can, in some circumstances, exit as a high pressure stream that is colorless and shows no vapor until it cools and spreads. A steam jet like this can cut off arms and legs or anything else exposed to it. These are best found with a broom stick or 2x4. (The steam jet will cut the stick or 2x4 in pieces or jerk it right out of your hand.)
From an NTSB report:
On June 16, 1995, the firebox crownsheet of Gettysburg Passenger Services, Inc., steam locomotive 1278 failed while the locomotive was pulling a six-car excursion train about 15 mph near Gardners, Pennsylvania. The failure resulted in an instantaneous release (explosion) of steam through the firebox door and into the locomotive cab, seriously burning the engineer and the two firemen. This accident illustrates the hazards that are always present in the operation of steam locomotives. The Safety Board is concerned that these hazards may be becoming more significant because Federal regulatory controls are outdated and because expertise in operating and maintaining steam locomotives is diminishing steadily. As a result of its investigation, the National Transportation Safety Board issued safety recommendations to the Federal Railroad Administration, the National Board of Boiler and Pressure Vessel Inspectors, and the Tourist Railway Association, Inc.
Safety appliances are those devices that protect, warn, and show the condition of a boiler in operation. If ignored and not maintained, the boiler will—not may— will eventually kill the crew and destroy the locomotive.
The first of these safety devices are the gauge cocks. These are three valves connected into the backhead of the boiler at set heights related to the crown sheet. The lowest is three inches above crown sheet height, the next an exact distance above it and the third above the second. The gauge cocks cannot be allowed to become clogged since they give the best warning as to the true level of water in the boiler. They are manually operated and must be checked before operation and at specific times during operation.
The next safety device is the water glass. This is also connected directly into the boiler, at a height so that the bottom of the glass is above the crown sheet. The 1999 Federal Regulation requires two water glasses on all steam locomotives.
Another safety appliance is the safety release valve (also known as pop valve). This is a valve set in to the top of the boiler that will open if the steam pressure in the boiler exceeds the operating pressure. Usually there are three, each set at two to three pounds more than the first, and each able to vent off all the steam in the boiler.
Additionally, each boiler must have two separate ways of feeding water into it, each capable of forcing water in against operating pressure. Also of great importance is the steam gauge. This indicates the pressure in the boiler and is used to check the performance of the pop valves.
Finally, the crew must use the safety appliances. Sight glasses and gauge cocks that are clogged or not watched don't give warning. Pop valves that are tied down or jammed won't relieve pressure, and water injectors that don't inject won't raise the water level. It is worth going to the accident report and the upgraded rules. Please see note one at the end of this article for links and more information.
Design of a Boiler
Boilers are devices that allow the transfer of energy, in the form of heat to water. The water transforms to steam and is released in a controlled manner to another device where it performs work.
Another class of boiler is used to transfer heat to environmental areas, either industrial or residential heating. In this form, the water is heated to a temperature below boiling, and distributed via pipes and radiators in the spaces to be heated.
What a Boiler Needs
To successfully convert energy to work, the boiler needs a heat source, a sealed container for the water, a method to transfer the heat to the water, a way to add more water, a way to control the combustion gasses, and a way to remove the steam in a controlled manner.
Heat is usually supplied by combustion. This combustion is performed in the firebox. A firebox is an enclosed space that has inlet ports for fuel and air so as to support combustion. Usually the firebox is surrounded on the top and four sides by a water jacket. The water jacket and top account for 40% or more of the heat transfer. The back of the boiler or firebox is called the backhead, and is composed of an inner and outer wall connected by staybolts, large metal rods that provide support to the parallel walls. The sides of the firebox are called the legs and are also composed of inner and outer walls supported by staybolts. The front of the firebox is composed of an inner wall and an outer wall supported by staybolts. Of note is the inner wall (called the rear sheet) that extends upward and is pierced to support the flues that allow the combustion gasses to flow to the front of the boiler and allow more heat transfer. The top of the firebox is composed of an inner wall and an outer wall connected again by staybolts. The inner wall is called the crown sheet, and is attached to the inside walls of the backhead, the legs, and the rear sheet. The outer wall of the firebox is called the wrapper, and is connected to the outside walls of the backhead, legs, firebox front, and the drum of the boiler. The sides of the firebox that are exposed to direct flame are lined with firebrick, and a damper arch is sometimes also included. The bottom of the firebox is composed of grates (coal) or by a solid sheet covered by fire brick (oil). Air is provided by openings in the grate or bottom sheet.
The main body of the boiler is called the drum, and attaches to the firebox and the front sheet. Within the drum, between the front and rear sheets, are the flues or tubes. On top of the drum is a dome or chamber where the dry pipe collects the steam and carries it out of the boiler. Finally, the top half of the front and rear sheet may be supported by braces from the sides of the drum to the inside of the sheet. The dry pipe extends into th
e steam collection dome and often contains the steam supply valve. The dome is also often used as the manhole or access point into the boiler for maintenance. Connected to the front of the drum is the smoke box, that has the smoke stack and spark arrester. Exhaust steam is released up the smoke stack to promote draft.
Figure 1
What a Boiler Burns
Combustion requires fuel. Wood, coal, natural gas, and oil are the most common fuels used although almost anything combustible can be used. Firebox design depends greatly on fuel type. Coal and wood require grates and ash pans, with air coming from below to support the fire. Oil is normally injected from the front bottom of the firebox, and sprays from a duck foot nozzle impelled by steam. Air is supplied by vents built into a plate closing the bottom of the firebox. Oil also needs heat applied to the fuel tank because Bunker C oil at room temperature is about the same thickness and consistency of peanut butter. To start combustion with this stuff "house steam," steam supplied by the shop or maintenance facility, is needed.
Boiler Materials