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Old 01-15-2013, 09:44 PM   #131
David Johansen
 
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Default Re: GURPS Releases seem to be slow?

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The T4 iteration of FF&S was more detailed, if almost totally unusable due to the incompetence of IG at editing, layout, and typesetting.
heh...I still have the 14 odd pages of erratta for that one...and the really nice sensor rules by the radar physics specialist that he offered to give to Imperium Games if they paid him what they owed him...really though it's a tragedy that book didn't get a proper printing.

I'd be fine with a spaceships style vehicle design system. I do love the 3e version though. The problem is that vehicles are an important part of many systems and hugely under supported as SJG always intended them to get their own book and left them out of many books they should have been in.
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Old 01-15-2013, 11:38 PM   #132
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Default Re: GURPS Releases seem to be slow?

Just as a side note, I want to mention the single thing that caused me more perplexity than anything else in using Vehicles for 3/e: Ship displacement.

Ships are traditionally rated in tons, a "ton" actually being a unit of volume: 35 cubic feet (approximately 2,240 lbs., or a long ton, if filled with salt water). That's the volume of water that the ship displaces if filled to its rated capacity. But it's not the total volume of the ship; it's only the part of the volume that's below the waterline.

In ship design calculations, this is treated as the body of the ship. But how do you handle the part of the ship that's above the waterline? Do you treat it as superstructure? That seemed really weird, as it's not actually a separate part of the ship (whereas the castles on a sailing ship were describable that way).

And what percentage of the ship is below the waterline? For the Monitor, it seems to have been around 90%. For normal ships, is it two-thirds, half, one-third, one-tenth? Guidelines would help in coming up with ship designs that make sense. Not having them had me scratching my head a lot.

Bill Stoddard
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Old 01-16-2013, 01:00 AM   #133
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Default Re: GURPS Releases seem to be slow?

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PS: Due to changed circumstances, I now plan on devoting time to Vehicle Design next month, with the aim of moving the project significantly forward.
Hooray! And there was much rejoicing.
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Old 01-16-2013, 01:07 AM   #134
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Default Re: GURPS Releases seem to be slow?

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Originally Posted by whswhs View Post
Just as a side note, I want to mention the single thing that caused me more perplexity than anything else in using Vehicles for 3/e: Ship displacement.

Ships are traditionally rated in tons, a "ton" actually being a unit of volume: 35 cubic feet (approximately 2,240 lbs., or a long ton, if filled with salt water). That's the volume of water that the ship displaces if filled to its rated capacity. But it's not the total volume of the ship; it's only the part of the volume that's below the waterline.
Displacement tons are actually a measure of mass -- it's just that mass is computed by determining the volume of water displaced. Just set the ship's weight to its displacement and give it however much volume you need for the components. Note that register tons (used for freighters) are in fact a unit of volume, equal to 100 cubic feet of cargo space.
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Old 01-16-2013, 01:50 AM   #135
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Default Re: GURPS Releases seem to be slow?

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Originally Posted by whswhs View Post
Just as a side note, I want to mention the single thing that caused me more perplexity than anything else in using Vehicles for 3/e: Ship displacement.

Ships are traditionally rated in tons, a "ton" actually being a unit of volume: 35 cubic feet (approximately 2,240 lbs., or a long ton, if filled with salt water). That's the volume of water that the ship displaces if filled to its rated capacity. But it's not the total volume of the ship; it's only the part of the volume that's below the waterline.

In ship design calculations, this is treated as the body of the ship. But how do you handle the part of the ship that's above the waterline? Do you treat it as superstructure? That seemed really weird, as it's not actually a separate part of the ship (whereas the castles on a sailing ship were describable that way).

And what percentage of the ship is below the waterline? For the Monitor, it seems to have been around 90%. For normal ships, is it two-thirds, half, one-third, one-tenth? Guidelines would help in coming up with ship designs that make sense. Not having them had me scratching my head a lot.

Bill Stoddard
Anthony is correct. A ship's "displacement" tonnage ("the Nimitz is about 100,000 tons") is its mass in long tons. Be very careful when dealing with anything that is a commercial vessel (as they sometimes use one of several other tonnages, some of which do nothing but measure the size of the cargo hold ) or anything from before the 20th century.

If it sets "displacement tons" it's mass, however.

What you can do once you have displacement tons is take the assumption that each long ton requires about 35 cubic feet of volume to keep the ship from sinking. Then, since in practice most ships other than something like the Monitor or a submarine aren't semi-submersibles, so about twice that or 60-80 cf per long ton is actually a decent rule of thumb for hull volume for most metal hulled ships including warships and ocean liners, and not really bad for larger ocean going wooden craft either. I'd be leery of applying it to galleys and especially to smaller boats.

Thus, a 50,000-ton ship might be estimated as having perhaps a 3.5 million cubic foot hull. Except for some modern cruise ships which have a very large superstructure, the latter adds about 10%-15% for most freighters and warships to about 20-30% for liners.

Another approach to measure hull is detailed geometrical analysis if you want to do lots of plans, or otherwise length (ignoring anything sticking out too far) times width times height from bottom to main deck. As ships aren't cubes multiplying that by about 0.55 to 0.67 for most modern ships generally gives the right ballpark.

If actually using the Vehicle design rules, there is a reason the design rules have worked "in reverse" and that is that years of testing have shown me it is a reasonably accurate way of calculating the actual volume, much more so than geometrical analysis, especially for oddly shaped designs. Look up the major components, install them first, follow the guidelines on accessible space, and that will usually actually give you a quite good estimate of the "real" volume. If anything seems too big, slap it into a superstructure.

My own practice is to use all three methods if necessary, but any two of them can check one another and give a rough estimate.
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Old 01-16-2013, 02:18 AM   #136
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heh...I still have the 14 odd pages of erratta for that one...
Considering they failed to notice that their layout software had translated all multiplication symbols to ¥ symbols, expecting them to notice more subtle errors such as unparseable text is pretty unlikely.
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Old 01-16-2013, 02:26 AM   #137
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Default Re: GURPS Releases seem to be slow?

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And what percentage of the ship is below the waterline? For the Monitor, it seems to have been around 90%. For normal ships, is it two-thirds, half, one-third, one-tenth? Guidelines would help in coming up with ship designs that make sense. Not having them had me scratching my head a lot. Bill Stoddard
The trick to doing this is to find the Draft. This stat is often listed in ship statistics which quote the draft and the length and width but cruelly fail to list the depth of the hull.

First, find a picture that shows the entire hull, not just the waterline. This is sometimes hard to get, though you may find diagrams in good reference books or dry dock photos, but I've found the best choice for any ship remotely famous is to search (google images, at museum, in a catalog etc.) for a model of it, as ship models usually show the entire hull, not just the waterline.

With a known length and the model as a reference you can easily find the depth of the hull, i.e., the distance from bottom to the main deck just by measuring the depth as a ratio to length, and then multiplying by known length.

Then it is simply (Draft / Depth) x 100 = % of ship below the waterline.

Obviously enough, iif you know the displacement tonnage, the draft, and the depth you can then get the *precise* hull volume:

Tonnage (long tons) * Draft (feet) * 35 / Depth (feet) = Hull (cubic feet).
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Old 01-16-2013, 02:29 AM   #138
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Default Re: GURPS Releases seem to be slow?

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Considering they failed to notice that their layout software had translated all multiplication symbols to ¥ symbols, expecting them to notice more subtle errors such as unparseable text is pretty unlikely.
Yeah, that was... uh, not very good. Kind of like how I feel, with flu now.
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Old 01-16-2013, 02:47 AM   #139
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I've actually used those before for a water-dwelling species' spaceship. What I was asking is how can I used that to get statistics for a sailing ship? Have I overlooked something? Would sails/rigging count as a system/design switch/feature? If so what would the cost and other stats be? What would the speed of such a vessel on water be? This is pretty much the only thing stopping me from creating fantasy airships like those seen in early Final Fantasy games, the Stardust movie, etc.

Edit: And thank you for responding! I highly appreciate it. :-)
You're welcome. Ah, I see. No, I haven't supported sails (as opposed to space sails) for water movement yet, just the screw propeller.

Here's how to cheat.

1) Please note that Ether Sails (in the Ether Propulsion section of Spaceships 7) are described as about the same size as normal masts and sails and capable of functioning as them. Divide the cost by some reasonable figure if you want non-ether masts and sails, I'd suggest by 5. Say you can have up to 4.

2) In the Pyramid article, use the same propulsion values for Sails as you would for screws, except read "power" as "number of sail or ether sail systems". For acceleration use 0.25 per system (assuming good wind).

3) Assume this is with the best wind; apply the usual sailing suggestions in Low Tech for less optimum winds or just halve again for normal conditions.

This is a bit optimistic, but perhaps not unduly so. Thus 3 sails systems (=3 power) at SM +7 gives, I think, 17, which we halve to move 8.5 (17 mph), and that's with the best wind; we'd get 8.5 mph under most circumstances.

Likewise acceleration is usually half power; now its 0.75.

A bit of a kludge, but might work. Try it and modify it to taste.
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Old 01-16-2013, 03:01 AM   #140
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Default Re: GURPS Releases seem to be slow?

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If it's anything like Vehicles 2nd Ed. it'll be putting parts together to make something that should, in theory match real-world equivalent within a reasonable margin of error and to provide a framework for producing internally consistent fictional designs. You won't count every nut and bolt (or even fully separate the engine, transmission and drive train) but it can be pretty detailed. I recall designing a space fighter to be an exercise in anal retentive detail and you end up counting tenths (or even hundredths) of pounds and pennies in the end.

I wouldn't use it to create existing designs where real-life stats are available (though guidelines for getting some of the stat block from real life performance would be nice).
A few guidelines for this are included in the system as short "Describing Vehicles" an appendix.

For those not familiar:

Mostly the fun or frustrating part of Vehicles is that since just about everything in the universe can be a vehicle, it provides an extensive nuts-and-bolts tech infrastructure for GURPS for those who like it. But it's a very "bottom down" system taking an atomic view of everything - you don't pick power plants that are ready to use (for instance); rather you'd consult a table that gives the weight, volume, cost, and fuel consumption per kilowatt of power output for, say, a dozen different internal combustion engine categories e.g., high-speed diesel or turbocharged gasoline engine, over 3-4 TLs, these figures derived from me researching rough averages of real values in each period. And you do this multiple times for each of the 20-30 major components in your vehicle...

(Of course, over time you build up a library of per-built modules, but the first few times it can take quite a while).

The main advantage is the "build anything" focus of it - with everything ground up, you can consistently define, say, vehicle with 4 legs, a head turret, a tail arm, steam power, flapping ornithopter wings, and a high performance supercharged diesel and call it a diesel punk robot dragon. Or go to "cyborg brain" section and install a human brain. Or go to the weapon section and create a flame thrower so it can breathe fire. And go to the structure section and give it an orichalcum skeleton and an aramid-fiber (kevlar) skin over its body. And then go to the section on building natural weapons and give it claws and fangs and a powered jaw. And then go completely insane and add a chameleon system and a small cramped internal seat so someone can ride inside. And then drive yourself crazy by spending 2 hours or so working through the ground and air perforamnce chapters trying to calculate whether it has enough of a power to weight ratio to lift off, and if necessary going back and trying to add a bigger engine, or realizing you forgot the fuel tank. The current edition at least has a few more pointers to cover this.



It's kind of super complex - legendarily so - and is famous for requiring complicated math like assuming you have a calculator (or can use Google) to find a square or cube root, and it's only somewhat realistic (it takes a broad view) but it is detailed. So in addition to building vehicles, you can build, say, radios, or radars, or fishing gear, or laser designators, or life support systems or find out the weight per point of DR per square foot of bronze armor (useful for making iron golems or armoring your house or if you know the area of a human being, a breast plate) and so on. Kind of amusing to play with that.
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