Wet Navy Ship Design

[Timerover51]

In the Wet Navy design sequence, three types of steam reciprocating power plants are mentioned: Primitive, Early, and Steam. I am making the assumption that this refers to the three stages of expansion that the steam reciprocating plant went through. Primitive is simple expansion or single pass-through, Early is the compound engine which processed the steam twice for double expansion, and Steam being the developed triple-expansion engine which passed the steam through a series three expansion cylinders.

I found the following article online, and it shows the general interior arrangement, both fore and aft and in cross section of the French Pre-Dreadnought Jaureguiberry, laid down in 1891, and commissioned in 1897. Earlier in this thread there was a discussion as to whether or not the boilers and boiler space for a steam reciprocating plant were included in the steam reciprocating plant volume and weight. I maintained that they were not, others maintained that they were. First, take a look at the line drawing on the website;

http://en.wikipedia.org/wiki/French_battleship_Jaureguiberry

I have the same images in my copy of the 1896 Brassey Naval Annual, so finding them already online meant that I did not have to scan them in and upload them somewhere.

Wikipedia gives the ship 12,441 Indicated Horsepower, Brassey lists her at 12,200 Indicated Horsepower, so I will assume that the 12,441 IHp was the trial output. As she is triple expansion, power output per cubic meter is listed as 120 kilowatts. Converting IHp to Kilowatts gives an output of 10,769 kilowatts. Dividing 10, 769 by 120 gives me 89.74 cubic meters, so call it 90 cubic meters for the volume of the power plant based on the Wet Navy design rules. The ship had a draft of 8.45 meters, and I allowed 1 meter for space for the double bottom, which might be a bit low, but does allow for more volume for the engine room. The beam of the ship is 23 meters, and allowing for say, one-half of the beam for coal bunkers abreast the engine and boiler rooms, that would give an engine room width of 11.5 meters. Multiplying 7.45 meters time 11.5 meters gives me a engine room volume of 85.675 cubic meters per meter of engine room length, fore and aft. That is just a little less than the 90 meters computed for the entire engineering plant volume. I did not allow for any scale efficiency, as that just makes it even worse, giving a volume for the engine plant of 59.8 cubic meters. Take either answer, 90 cubic meters or 59.8 cubic meters, and look at the drawings. I submit that the power plant calculations and design do not take into account any boilers for the steam plant, and based on the volume of the boiler room alone, do not come close to reflecting that either. That would extend through the design for steam turbine plants as well.

I also got out my copy of British Battleships 1889-1904, by R. A. Burt, and ran calculations for the British battleship Majestic, viewed as the first true Pre-Dreadnought battleship launched, using the weight of the Majestic power plant, I do not have the weight of the plant of the French ship, and compared that to the design sequence result based on weight. Using the results of the forced-draft trial run for the Majestic, I had 12,554 IHp, which converts to 9361 kilowatts. The ship had a triple-expansion engine, so power output is 120 kilowatts per cubic meter of volume which weighs 4 tons. Without any scaling factor that gives a weight of 312 tons, with scaling you get a weight of 208 tons. The actual weight of the Majestic plant was 1,356 tons. The weight of the plant is badly off as well.

I will work through the Burt book, as he does give information on costs of power plant and guns for some of the ships, as well as boiler and engine room length, and some information on engine room crews. I will also get out my copy of Admiral King's Warships and Navies of the World-1880 to see if I can get more information on engine room crews and crews required for sailing. The Burt book gives some information on sailing rig for the older British ships as well.

 

[PFVA63]

Hi,

If you don't mind dealing with Russian language sites, there are some very helpful info on Pre-Dreadnought vessels at this site ( http://www.wunderwaffe.narod.ru/ ) particularly in the Magazine/BKM subsection ( http://www.wunderwaffe.narod.ru/Magazine/BKM/ ). You can typically use something like Google Translate or something similar to get a fair idea of the text.

At these links there are scans of several Magazines and the Чертежи link will take you to the scans of the lines drawings and such within them. Here is an example of one of the deck plans of the Imperial Russian Pre-Dreadnought Tsesarevich showing some of the machinery spaces.



http://www.wunderwaffe.narod.ru/WeaponBook/Cesarevich_1/Draw/21.jpg

Using data like this might give you a better chance at estimating the size of the machinery spaces on some existing ships.

PF

PS. When the Challenge stuff first came out I was really interested in trying to design some ships similar to existing ships from history, but over time I began to realize that the rules in them may not have been all that accurate estimations of stuff from our history

PPS. Alternately, you can also order copies of a lot of these Russian Magazine articles on Pre-Dreadnoughts off sites like eBay, etc. I picked up such a CD last year.

 

[PFVA63]

Hi,

In addition to the above, I almost forgot, the book "Warrior to Dreadnought" has some really useful data and plots on pre-dreadnought type ship weights including really nice graphs showing;

sq ft of deck plate area required per ihp vs the date the ship was built
ihp/ton vs date the ship was built
coal consumption in terms of lb*ihp/hr vs date the ship was built
Hull Weight divided by Cubic Number vs date the ship was built (where Cubic Number = Length x Beam x Depth/1000)

that can be very helpful as well.

 

[Timerover51]

Hi,

In addition to the above, I almost forgot, the book "Warrior to Dreadnought" has some really useful data and plots on pre-dreadnought type ship weights including really nice graphs showing;

sq ft of deck plate area required per ihp vs the date the ship was built
ihp/ton vs date the ship was built
coal consumption in terms of lb*ihp/hr vs date the ship was built
Hull Weight divided by Cubic Number vs date the ship was built (where Cubic Number = Length x Beam x Depth/1000)

that can be very helpful as well.

That is the D. K. Brown book? A lot of that data is also in the Burt book on British Pre-Dreadnoughts. I was thinking about getting that one anyway next month. I have the John Riley book on US Pre-Dreadnoughts, and all of the Norm Friedman US warship design and development books as well.

With respect to the Russian pre-dreadnoughts, a lot of them were built in other countries, including the Retvizan, built by Cramp's in Philadelphia. There are some good drawings in the Brassey's as well.

 

[PFVA63]

Hi,

I scanned and plotted the data above from D.K. Brown's book, digitized and replotted it, and did a little curve fitting, as shown below.

I don't know if it'll help you any, since most of the plots are versus date in service (which may or may not relate to verious point in Traveller's Tech Level tree), but you may want to take a look at them anyway if you wish.









http://www.mnvdet.com/Other/Hull Wt.png
http://www.mnvdet.com/Other/iHP per Ton.png
http://www.mnvdet.com/Other/Machy Space per iHP.png
http://www.mnvdet.com/Other/Coal Consumption.png

 

[Timerover51]

Greetings and thanks for the data work. I have the D. K. Brown book on the way, along with the Burt book on British World War One Dreadnoughts to go with his book on Pre-Dreadnoughts and his book on the World War Two ships.

With respect to hull weight, you are going from the wrought iron of the Warrior to the steel of the Dreadnought, so you should show a progression to lighter hulls. I will need to see in the Brown book what ships he is using, as you also are going to get a reduced structural weight from the gradual shift in armor from wrought iron to Krupp face-hardened steel, as the weight of hull needed to support 16 to 24 inches of wrought iron armor along with a fairly thick teak backing it reduced.

For your indicated horsepower per ton of machinery weight, are you using the rated output of the plant or the output under forced draught, which could be considerably higher, but also tended to caused major problems for the boilers? Based on the Burt Pre-Dreadnought book, the British used the basic plant of the Royal Sovereign-class for several of the succeeding classes and ships, gradually tweaking it to boost the power output. They then jumped from 155 psi boilers to 300 psi boilers, which boosted output. Also, is his plant weight including water in the plant or not, as that can vary things by about a 100 tons or so?

With machinery space, you are going from box boilers with 20 to 30 psi steam to water-tube boilers off up to 300 psi steam, along with going from simple direct-connection engines to fairly sophisticated triple-expansion engines, so volume will reduce per horsepower of output, but you also have increased horsepower required, so machinery spaces do not really shrink. I have data on a lot of them to work with.

Lastly, I cast a jaundiced eye on rated coal consumption if it is based on trial figures. In King's Warships and Navies of the World-1880, King gives a detailed report on how ship trials of a steam plant are conducted, to include highly trained stokers and coal heavers and carefully selected coal to give maximum heat and minimum ash, as well as not using all of the auxiliaries that use steam and coal without producing motive power. Overall, the general trend does improve for lower coal consumption.

 

[Timerover51]

As for TLs, while MT:RM (page 23) puts the change from TL3 to TL4 about 1900, in fact most of the TL4 items shown in the tables in page 28/29 of the RC appeared on the second half of XIX century, and its equivalence would be more, IMHO, Victorian age, while TL5 would be WWI and TL6 WWII to Korea.

Specifically in naval terms, I'd set TL4 from the appearence of the steam engine to the developement of the Dreadnought, and TL5 from the Dreadnought to the Carriers age. Purely my oppinion, of course.

My apologies for resurrecting this thread, but this post from McPerth deserves an answer, since I just discovered that I had a copy of the MegaTraveller Referee Companion stashed away in a plastic bin in my garage.

You are quite correct that many of the TL 4 items shown actually appear in the middle to late period of the 19th Century or Victorian period. I guess the thing that puzzles me is why MegaTraveller kept using 1900 as the starting point for TL 4.

There are some puzzling items though under TL 5. Explosive grenades appear in the 1600s, which is when you start seeing Grenadier companies and units as elite units in an army. Shotguns, specifically date from circa 1850, when rifles start appearing as commonplace weapons, as firing birdshot from a rifled barrel does not work very well. The first automatic pistol dates from 1893, and by 1910, you had the Luger, Mauser, and Browning automatic pistols on the market. The Maxim machine gun dates from the 1880s, while grenade launchers were widely used in World War 1, and mortars date from the late 1500s.

 

[whulorigan]

You are quite correct that many of the TL 4 items shown actually appear in the middle to late period of the 19th Century or Victorian period. I guess the thing that puzzles me is why MegaTraveller kept using 1900 as the starting point for TL 4.

In MT (and TNE), the TL is not the starting point, but rather the midpoint of the TL. So "ca 1900" for TL4 means that the year 1900 is the exact middle of what is considered TL4. It shades back toward TL3 as you approach the year 1800 (the "midpoint" of TL3), and shades into TL5 as you approach the year 1930 (the "midpoint" of TL5).

It is another way of saying that "classic TL4 technology" is represented by Terra in the year 1900.

So the year 1875, for example, is somewhere along the spectrum between TL3 and TL4 (i.e. it is early TL4), just as 1915 would be late TL4 to early TL5.

 

[Timerover51]

In MT (and TNE), the TL is not the starting point, but rather the midpoint of the TL. So "ca 1900" for TL4 means that the year 1900 is the exact middle of what is considered TL4. It shades back toward TL3 as you approach the year 1800 (the "midpoint" of TL3), and shades into TL5 as you approach the year 1930 (the "midpoint" of TL5).

It is another way of saying that "classic TL4 technology" is represented by Terra in the year 1900.

So the year 1875, for example, is somewhere along the spectrum between TL3 and TL4 (i.e. it is early TL4), just as 1915 would be late TL4 to early TL5.

That does not deal with some of the weapon developments being so far off. I am not sure I would call the bombards that the Turks used in 1453 on the walls of Constantinople as "small cannon".

What you say might work for some, but Tech Level 0 is Stone Age, Tech Level 1 is Middle Ages, Tech Level 2 is 1600, and Tech Level 3 is 1800. Figuring that the Stone Age, at least for Egypt and Mesopotamia ended around 3000 BC, with the Middle Ages running from say 500 AD with the extinction of the Western Roman Empire to, by your reasoning, 1500 AD, the Middle Ages are by no means halfway between 3000 BC and 1500 AD. Then from Tech Level 5 to Tech Level 9 you have 20 year jumps. Then a jump from circa 2010 for Tech Level 9 to 2100 to Tech Level 10, with Tech Level 8 at 1990.

There are other odd things in the Tech Level chart in the Referee Companion under Environment.

Irrigation is under Tech Level 1 or the Middle Ages. Hmm, the Egyptians and Sumerians would probably be more than a bit surprised by that.

Cities, canals, bridges, and roads fall under Tech Level 2 or circa 1600. Guess all of those Roman roads, bridges, and aqueducts were figments of the World's imagination, to say nothing of Rome, Athens, Constantinople as cities. They must have been somewhere between "crude huts" to "settlements" or "towns".

Not sure that I want to continue this, but too many things in that chart are odd.

 

[whulorigan]

That does not deal with some of the weapon developments being so far off. I am not sure I would call the bombards that the Turks used in 1453 on the walls of Constantinople as "small cannon".

What you say might work for some, but Tech Level 0 is Stone Age, Tech Level 1 is Middle Ages, Tech Level 2 is 1600, and Tech Level 3 is 1800. Figuring that the Stone Age, at least for Egypt and Mesopotamia ended around 3000 BC, with the Middle Ages running from say 500 AD with the extinction of the Western Roman Empire to, by your reasoning, 1500 AD, the Middle Ages are by no means halfway between 3000 BC and 1500 AD. Then from Tech Level 5 to Tech Level 9 you have 20 year jumps. Then a jump from circa 2010 for Tech Level 9 to 2100 to Tech Level 10, with Tech Level 8 at 1990.

There are other odd things in the Tech Level chart in the Referee Companion under Environment.

Irrigation is under Tech Level 1 or the Middle Ages. Hmm, the Egyptians and Sumerians would probably be more than a bit surprised by that.

Cities, canals, bridges, and roads fall under Tech Level 2 or circa 1600. Guess all of those Roman roads, bridges, and aqueducts were figments of the World's imagination, to say nothing of Rome, Athens, Constantinople as cities. They must have been somewhere between "crude huts" to "settlements" or "towns".

Not sure that I want to continue this, but too many things in that chart are odd.

I wasn't suggesting that there are not odd things in the chart. I was merely pointing out that I am fairly certaiin that the example dates given are meant to represent the "middle" of the period in question, when a precise date is given as an example (e.g "ca 1800", as opposed to "Middle Ages", which is not a date).

Several things to keep in mind, however:

1) The dates or peiods given are meant to be an approximation, not a precise 1-to-1 correspondence;

2) MT uses an extended TL code according to World-Builders Handbook, with precise TLs given for particular fields and areas of technology. Thus, any given world may be one or two TLs different in either direction from the "general" TL listed in the UWP.

3) The UWP TL code (at least in theory) is meant to be broad, covering the general TL progression of a number of different cultures, both historical and "current" from the standpoint of the Third Imperium. The TLs given are likely influenced by the historical Vilani progresion of TL as well. It may be true that Terra was using a given technology at a given date in history (compared to other inventions in use at the same time), but that doesn't mean that all cultures followed the exact same progression. The TL dates given are a general (broad) guideline.

4) Do not presume that the TL progression given means that Terra had a "steady" and uniform progression over time until the present. It may very well be that Ancient Rome was considered to be "Late" TL1 (with some TL2 inventions), and then fell back to average TL1 during the Dark Ages, only to regain Late TL1 to TL2 by the Renaissance.
​

 

[Timerover51]

Now that I have figured out how to get some images on here, this gives a good idea of the amount of space taken up by steam boilers in the late 1800s.

Note that the combination of the boilers and steam reciprocating plant take up about half of the length of the underwater portion of the hull of the ship, with the total volume being considerably greater than one-half of the underwater portion, as the boilers and power plant occupy the midships section, the broadest part of the ship.

 

[sfchbryan]

Before you guys get much deeper into this, might I suggest that all of you take some time to review Wood and Wind, Steam and Steel.

Most of what is being discussed here is covered in that.

Not to mention the fact that if you want a horribly over-engineered system that takes the granularity level to the point of ridiculousness, one does have T5.

 

[Timerover51]

Before you guys get much deeper into this, might I suggest that all of you take some time to review Wood and Wind, Steam and Steel.

Most of what is being discussed here is covered in that.

Not to mention the fact that if you want a horribly over-engineered system that takes the granularity level to the point of ridiculousness, one does have T5.

I have that one as well, legally purchased in both hard copy and download from DriveThru. What I am working on is a system that plugs boilers into the steam-powered plants volume, depending on whether you are using simple reciprocating, compound, or triple expansion steam plants. Turbines are somewhat different.

 

[sfchbryan]

I have that one as well, legally purchased in both hard copy and download from DriveThru. What I am working on is a system that plugs boilers into the steam-powered plants volume, depending on whether you are using simple reciprocating, compound, or triple expansion steam plants. Turbines are somewhat different.

So, just exactly what do you gain, in game terms?

 

[snrdg082102]

Evening sfchbryan,

So, just exactly what do you gain, in game terms?

My guess from discussions for TNE Striker is a closer fit to the real world when building hulls and weapon systems. Of course I am probably out to lunch with my guess.

 

[aramis]

My guess from discussions for TNE Striker is a closer fit to the real world when building hulls and weapon systems. Of course I am probably out to lunch with my guess.

None of them do canoes particularly well - WWF&S does the best of the published systems so far that I've used (which excludes T5). None even came close to the 50-70 pounds of the Aleut, Alutiiq, and Yupiq kayaks...

A local manufacturer has a specifications page:
http://watercraft.clearstreamwood.com/products/kayaks/skin-on-frames/

They're using traditional methods and materials.

Irony note: Composite kayaks actually are heavier.

 

[snrdg082102]

Evening aramis,

None of them do canoes particularly well - WWF&S does the best of the published systems so far that I've used (which excludes T5). None even came close to the 50-70 pounds of the Aleut, Alutiiq, and Yupiq kayaks...

A local manufacturer has a specifications page:
http://watercraft.clearstreamwood.com/products/kayaks/skin-on-frames/

They're using traditional methods and materials.

Irony note: Composite kayaks actually are heavier.

In my opinion none of the Traveller design systems do very well at creating very small vehicles such as canoes, kayaks, motorcycles, bicycles, small aircraft, etc.

 

[Timerover51]

So, just exactly what do you gain, in game terms?

First, how much volume and mass of the ship is taken up by the power plant verses what is left for weapons and armor. Second, a major difference in coal consumption between simple, compound, and triple-stage reciprocating plants. Generally, the hull would weigh about 40% of the mass of the ship, while machinery plant, armor, and weapons would split the remaining 60%.

Upgrading an early ship's boilers and power plant could result in either doubling or tripling the range of the vessel, freeing up more weight for weapons or armor (taking stability into consideration), or improving the protection of the vessel by reducing the loaded draft and/or allowing additional coal to be carried but not used. Two feet of coal equated to 1 inch of steel plate in resisting projectiles, so a full 5 foot deep coal bunker would add 2.5 inches of protection to the armor of the ship, as well as improving its resistance to torpedoes.

A cubic foot of coal weighs 85 pounds, and allowing for 85% bunker loading and space for coal passages from bunker to boiler rooms, one Traveller Displacement ton of approximately 476 cubic feet will hold 12.5 tons of coal.

 

[snrdg082102]

Upgrading major systems like ship's boilers and power plants also change the vessel's buoyancy and other characteristics originally calculated in the design sequence.

 

[Timerover51]

You might want to look at how thoroughly the British modernized some of the Queen Elizabeth-class battleships between World War 1 and 2.