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  #21  
Old November 29th, 2018, 07:44 PM
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Originally Posted by mike wightman View Post
Civilian - hull, controls, drives, fuel, cargo, crew, staterooms, hardpoints for turret weapons, carried craft/vehicles
Military - hull, armour, screens, EW, controls, drives, fuel, fuel treatment (or military spec drives), crew, staterooms, cargo/stores, hardpoints for turret weapons, bay weapons or setting equivalent, spinal mounts or their setting equivalents, carried craft/vehicles, ship's troops
Nice first cut for design. I think what I will do is determine any individual design based on what it is supposed to do. Is it going to be a Free Trader, picking up cargo where it can, delivering it and then looking for more cargo to take somewhere? Is it going to be a liner on a regular route, with guaranteed cargo and passengers at each stop? Is it going to be a small Space Viking raider, optimized for surface raiding? Then, looking at what those ships require, approaching it from the standpoint of building a surface merchant ship and a surface warship, and going from there.

I also need, as Aramis stated, to make sure that the numbers add up for a profitable or near-profitable ship. By near-profitable, I mean a ship that does need to do some speculative trading to keep the bills paid. As the Hyperdrive ships are going to inherently have more cargo capacity, how much more will the drives need to cost to keep Jump Drive ships competitive? As I will be planning for crew on the basis of 3 watches, my crew needs and costs are going to increase as well, by a factor of around 3. More number crunching. But then, such is the life of a ship designer. A ship is simply the result of a large number of trade offs.
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Old December 12th, 2018, 03:39 AM
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I was looking again at the ship construction rules, and thinking of some changes to be made.

First, the ships take way to long to build. A 5000 dTon ship is listed as taking 428 weeks to build. Converting that into standard Earth years of 52 weeks, that ship is taking over eight years to build, eight times fifty-two equalling 416 weeks. Now, 5000 Traveller dTons equates to about 25,000 Gross Register Tons for a nautical vessel. A World War 2 Liberty Ship, about the equivalent of 1420 Traveller dTons took an average of 9 months to build, in terms of man-hours, the shipyards ranged from 400,000 to 800.000, with the $2 Million price based on 600.000 man-hours. A larger ship does not take proportionately more time to build, as the larger ship allows for more workers to work on it. A 25,000 Gross Register Ton hull might take less than two years to build if a bulk carrier to 3 or so if a warship. Before someone says that the star ships have to be stronger than a nautical ship, consider that a merchant ship has to be able to survive the beating of a gale in the North Atlantic during the winter. The G-loads measured by research and weather hips can be quite impressive. So the cost of the hull should be proportionate to the increase in dimensions and ship volume, not simply jumping by an arbitrary number for every 100 tons of increased hull size.


Any ship built on a planet with an atmosphere from 4 to 9 is automatically streamlined with no extra cost. If atmosphere is less that 4, or the ship is built in orbit, then the increased cost is applied for streamlining. Building a ship on a vacuum planet or it orbit doubles the cost of the hull, as all workers need to be able to operate in a vacuum, and maybe in Zero-G.
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Last edited by timerover51; March 4th, 2019 at 11:21 AM..
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  #23  
Old December 21st, 2018, 02:06 AM
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Might it also depend on the material the ship's hull or armor is made from as well?

Like what kind of materials do ships use for armor in your setting?
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Old December 21st, 2018, 09:31 PM
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One thing High Guard did to balance the scales (other than armor) was to increase the volume requirement for maneuver drives.

It's a non-complicated change that creates a great difference between merchants, which can afford to be slow, and combat ships, which cannot afford not to be fast.

Basically, then, cargo space trades off for maneuver drive and armor.
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Old December 22nd, 2018, 01:17 AM
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Designs should be a series of compromises.
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Old December 22nd, 2018, 04:16 PM
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Designs should be a series of compromises.
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Originally Posted by timerover51 View Post
A ship is simply the result of a large number of trade offs.
Same idea, different wording. Warships are even worse when it comes to trade offs/compromises, as typically you have some bureaucrats who really do not know the technology writing the specifications.

One case I can think of was the U.S. Admiral in the 1950s who wanted a small and cheap destroyer with a sustained speed in a seaway of 30 knots. To meet the seaway speed requirement, the initial design came in at over 10,000 tons and was still questionable on making the speed.
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Old December 22nd, 2018, 06:00 PM
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Originally Posted by wellis View Post
Might it also depend on the material the ship's hull or armor is made from as well?
I am assuming that the standard merchant ship's hull is made from 40 pound/25 millimeter HY-80 steel, similar to what has been used in submarines. Over that is a layer of insulation, with a thin additional layer of highly reflective aluminum alloy. If the ship does not have retractable landing pads, then the insulation layer is inside of the steel hull on the bottom of the ship, along with an additional layer of structural steel to support the hull in landing.

Different materials will make a difference, as will going to a thinner steel hull for smaller ships. The 40 pound/one inch thick hull is definitely an overly conservative design, but it matches what I once calculated for ship hulls based on Supplement 7: Traders and Gunboats and the ANNIC NOVA adventure. I should note that this type of plating is much stronger than the plating used on current nautical merchant ships using mild steel, and in World War 2, HY-80 steel would have been classed as armor plating. You could build the ship hull out of mild steel of equal thickness for say one-half the price, and still have a very strong hull.

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Like what kind of materials do ships use for armor in your setting?
First, Titanium. Titanium and steel are two different materials entirely, so it would be more accurate to say Titanium plating. Titanium is lighter than steel and as strong, so that on a weight basis, a Titanium plate is gong to be thicker and as a result, much stiffer than a steel plate of equal weight and be much stronger in resisting impacts due to the greater thickness. It is also highly resistant to corrosion, and would be ideal for ships having to operate in corrosive atmospheres on a regular basis. However, it is also currently between 8 and 30 times more expensive than steel alloy plate. Now, assuming that in the future titanium processing technology improves so that plating is closer in cost to steel, I would assume the cost increase for a hull made of titanium with a weight equivalent of 40 pound steel plate to be 5 times as expensive. This will give you a corrosion-resistant hull, with the hull plating 3 times stiffer than steel of equal weight, resulting in fewer structural members being required, and about twice as hard to penetrate as an equivalent weight of steel. Considering the reduction in structural members required, resulting in fewer man-hours needed, I would say that a hull made of titanium should cost about 4 times that of a steel hull. That cost can be reduced by reducing the thickness of the titanium. As I have said, I am being overly conservative with my hull thicknesses.

Crystal Iron, I will simply say no, for what I regard as good and sufficient reasons that I do not wish to spell out here.

Superdense and Bonded Superdense. As I understand it, this is steel that has been collapsed into a smaller thickness, increasing its density, and therefore strength and resistant to penetration. First, you will need to fabricate the steel plating, correctly shape it, and then collapse the plating. That is going to take some form of sophisticated technology, which I cannot view as being cheap to make or use. You are going to need to correctly shape it before collapsing it, as once collapsed, you are not going to be able to shape it afterward. As I may be allowing collapsium in the sector, I have to make allowance for this. As to cost, I will be figuring Superdense at 20 times the cost of a standard steel hull, and Bonded Superdense at 100 times the cost of a standard steel hull. Essentially, that material will be for warships only.

Hull costs are going to be lowered, as that should compensate for some of the increase in cost of armor.

It should also be noted that steel and titanium plating, while good at stopping gamma and x-ray radiation, is not at all good for stopping neutrons, which was the reason for the neutron bomb. To stop neutrons, you want either very light material, or something with a very high neutron capture radius, like gadolinium or hafnium.
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  #28  
Old December 26th, 2018, 07:28 PM
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Quote:
Originally Posted by timerover51 View Post
I am working on a ship construction rules rewrite that is going to make military equipment a LOT more expensive. The same is going to happen with armor. Also, some of the weaponry carried is going to change. If you are primarily raiding surface targets, you are going to use a different set of weapons compared to space piracy. When you look at the career of Francis Drake, he spend more time raiding Spanish settlements that chasing Spanish ships. The buccaneers of the Spanish Main also did a lot of settlement raiding.
Need to make most basic construction far cheaper. Ships are typically built for $4k-5k per ton. Cruise ships with fancy decoration cost 24-50% more (a few are more extravagant). Military ships build for more like $25k per ton.


Compare to airliners that cost 100x as much, $500k per ton. Some even more. They are minimizing weight with very expensive materials and fit more stuff in per ton of mass. On a per volume basis it is closer to 50x the cost.


Now look at revenue. A cruise price is about $50 per m per day. An economy/business airline seat price is about $100 per m per hour.


Gawwwleee, look at that! Costs and revenue are balanced with air travel costs and prices about 50x cruise travel! Whodathunkit?



Traveller's error is making starship costs compare with airliner costs, and sets passenger and cargo rates that compare with cruise ships rates.
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  #29  
Old December 29th, 2018, 01:40 AM
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Quote:
Originally Posted by timerover51 View Post
First, Titanium. Titanium and steel are two different materials entirely, so it would be more accurate to say Titanium plating. Titanium is lighter than steel and as strong, so that on a weight basis, a Titanium plate is gong to be thicker and as a result, much stiffer than a steel plate of equal weight and be much stronger in resisting impacts due to the greater thickness. It is also highly resistant to corrosion, and would be ideal for ships having to operate in corrosive atmospheres on a regular basis. However, it is also currently between 8 and 30 times more expensive than steel alloy plate. Now, assuming that in the future titanium processing technology improves so that plating is closer in cost to steel, I would assume the cost increase for a hull made of titanium with a weight equivalent of 40 pound steel plate to be 5 times as expensive. This will give you a corrosion-resistant hull, with the hull plating 3 times stiffer than steel of equal weight, resulting in fewer structural members being required, and about twice as hard to penetrate as an equivalent weight of steel. Considering the reduction in structural members required, resulting in fewer man-hours needed, I would say that a hull made of titanium should cost about 4 times that of a steel hull. That cost can be reduced by reducing the thickness of the titanium. As I have said, I am being overly conservative with my hull thicknesses.
So essentially instead of "titanium steel", it would be instead more like "titanium alloy" or something like that?
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Crystal Iron, I will simply say no, for what I regard as good and sufficient reasons that I do not wish to spell out here.
I thought "crystaliron" was some sort of term used for monocrystalline steel, which is apparently much stronger due to being composed of a single crystal or something?
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Originally Posted by timerover51 View Post
Superdense and Bonded Superdense. As I understand it, this is steel that has been collapsed into a smaller thickness, increasing its density, and therefore strength and resistant to penetration. First, you will need to fabricate the steel plating, correctly shape it, and then collapse the plating. That is going to take some form of sophisticated technology, which I cannot view as being cheap to make or use. You are going to need to correctly shape it before collapsing it, as once collapsed, you are not going to be able to shape it afterward. As I may be allowing collapsium in the sector, I have to make allowance for this. As to cost, I will be figuring Superdense at 20 times the cost of a standard steel hull, and Bonded Superdense at 100 times the cost of a standard steel hull. Essentially, that material will be for warships only.
So which one would fit "collapsium" better in your mind? Would one be like called, in-setting, "Collapsium" and the other "Improved Collapsium"?
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Originally Posted by timerover51 View Post
Hull costs are going to be lowered, as that should compensate for some of the increase in cost of armor.

It should also be noted that steel and titanium plating, while good at stopping gamma and x-ray radiation, is not at all good for stopping neutrons, which was the reason for the neutron bomb. To stop neutrons, you want either very light material, or something with a very high neutron capture radius, like gadolinium or hafnium.
I forget but can water be used to protect against neutrons? I understand it is often thought of as a useful radiation shield in science fiction.
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Old December 29th, 2018, 03:14 AM
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Originally Posted by Straybow View Post
Need to make most basic construction far cheaper. Ships are typically built for $4k-5k per ton. Cruise ships with fancy decoration cost 24-50% more (a few are more extravagant). Military ships build for more like $25k per ton.
The World War 2 Liberty ship came in at a little under $300 per measurement ton, which is the closest that I can come to the Traveller dTon in terms of volume measurement. Now, the ship was built of mild shipbuilding steel, which actually would be adequate for Traveller ships. I could drop the HY-80 steel and go back to the vanadium steel alloy used by the World War 2 U.S. Navy in its later subs. Hulls made from that had a crush depth of over 900 feet, which was a problem as the rest of the sub equipment was not cleared to much over 450 feet. That steel was seven-eights of an inch thick, or 35 pound plate. Cut that to one-half inch and you still have a big safety factor. The main thing is holding one atmosphere pressure against a vacuum, and then handling 1.5 atmosphere pressure if landing on a Dense Atmosphere planet. I am using the rule-of-thumb equations for designing a submarine hull as my basic building rule.

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Compare to airliners that cost 100x as much, $500k per ton. Some even more. They are minimizing weight with very expensive materials and fit more stuff in per ton of mass. On a per volume basis it is closer to 50x the cost.

Now look at revenue. A cruise price is about $50 per m per day. An economy/business airline seat price is about $100 per m per hour.

Gawwwleee, look at that! Costs and revenue are balanced with air travel costs and prices about 50x cruise travel! Whodathunkit?

Traveller's error is making starship costs compare with airliner costs, and sets passenger and cargo rates that compare with cruise ships rates.
Well, I am adjusting those a well, as I am having two crew per stateroom, along with up the 4 passengers per stateroom, with the same life-suuport costs as one person. As I see it, the main life support factor is clearing the CO2 absorption filters, dumping the waste tanks, and replacing the food, with the food the greatest cost.

From Cepheus Engine SRD, page 109.
Quote:
Each stateroom on a ship costs Cr2,000 per month, occupied or not. This cost covers supplies for the life support system as well as food and water, although meals at this level will be rather spartan.
Why this is assumed I have not the foggiest idea. The Traveller Book has restaurant meals of ordinary quality costing 10Cr per day per person, with good food costing 200Cr per month. You are only feeding your passengers for two weeks of the month, so good food should cost 100Cr per month for one passenger, or excellent food would cost 300Cr per month. Forget the spartan meals, the passengers will be well fed.

As for cargo, I figure that the 1000 Credits per dTon is a volume charge, and if you go with speculative trading on a Free Trader, you can put more an a single ton of cargo in that 13,5 or 14 meter cubic volume. I keep looking a cube per ton of various cargos and keep debating allowing for 5 tons or 10 tons per Traveller dTon of cargo. I am still working on that. The thing is how to avoid making a Free Trader a cash cow. Against that, I also am looking at making maintenance a lot more expensive, and then there is this nasty thing called "Insurance".
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