Real life comparisons for dtonnage?

[Quint]

I was wondering of anyone had done any work in figuring out what the dtonnage of modern day vehicles would be in Traveller terms? I was interested in the numbers when it comes to moving them as cargo, simply to have a mental picture that I can compare to a physical object. I just took a gander at the size of an F-22, and it looks like ~ 18 meters long by 12 meters wide by 6 meters high (as a block of space, we assume it might pack a bit tighter, but probably not much).

That's pretty darn big!

In any case, was wondering if anyone had done the work already or could point me in the direction of someone who had?

Thanks!

D.

 

[infojunky]

I was wondering of anyone had done any work in figuring out what the dtonnage of modern day vehicles would be in Traveller terms? I was interested in the numbers when it comes to moving them as cargo, simply to have a mental picture that I can compare to a physical object. I just took a gander at the size of an F-22, and it looks like ~ 18 meters long by 12 meters wide by 6 meters high (as a block of space, we assume it might pack a bit tighter, but probably not much).

20 ft container is approx 4 dtons (it is smaller), a '73 Buick Sportwagon is approx. 2 dTons. Your average 1/2 bath with a shower is around 1/2 a dTon.

Aircraft are much larger than most people figure and even ones that fold up for spaces such as a Aircraft Carriers Hanger Deck are still very large. Helos are weirdly an exception they tend to fold down to a size that will fit into your average truck garage.

Remember this, 5 feet is real close to 1.5 meters. One game a mate and I used to play was to pace off random open spaces to see if we could fit a Scout Ship. (Though this game is easier for the players both have lots experiance with outside measuring, He is a Geologist with a fair amount of survey experience, and I am Geographer, so silly land measuring systems are a amusing pastime).

 

[Timerover51]

I have a lot of that in my various Transportation and Logistics manuals. Plus, you need to consider in loading vehicles that you will likely have them strapped down quite thoroughly on some form of shipping skid to move them on and off your ship, depending on their size and mass, and your ship configuration. You are not likely to have them packed too tightly, as you need space to strap them down.

The standard Traveller cargo module, that appears in Supplement 7, Traders and Gunboats, is 3 meters wide, 3 meters high, and 6 meters long, or 4 Traveller dTons. Looking at that from my perspective, that is a bit large for a cargo container, but that is what is given. I would lean towards a cargo module for dense cargo of 1.5 X 1.5 X 3 meters, which is in English terms, just about 5 feet X 5 feet X 10 feet, so 250 cubic feet, or 0.5 Traveller dTons.

For example, with respect to one of my favorite vehicles from World War 2, the Truck, Amphibian, 2.5 Ton, 6 X 6, the DUKW, or "Duck", here is how it would work. The DUKW is 96 inches/8 feet wide, 106.5 inches/just under 9 feet high, and 372.125 inches/31 feet long. That would occupy a space, in terms of your standard 1.5 meter square deck plan, of 2 squares wide/3 meters/10 feet by 7 squares long/10.5 meters/35 feet. A 3 meter/10 foot deck clearance would make it a bit tight height-wise, but could be done if driven on and off. Otherwise, from a loading standpoint, I would really like at least 4 meters or 13 feet of overhead. That would equal 7 Traveller dTons. The DUKW weighed in at 14,500 pounds empty, could carry 5,000 pounds of cargo in the water, and when loaded with cargo, fuel, oil, and radiator fluid, 19,850 pounds, or almost exactly 9 metric tons.

The reason that I would like a smaller cargo module for dense cargo, like rations, ore, metal, ammunition, that sort of thing, is handling it is easier. There is no provision in Traveller for what I call materials handling equipment, either on board the ship or at a port. Moving one of those standard Trader and Gunboat modules is going to be a major pain if it is loaded with dense cargo, as it could easily mass 20 or more tons. A cargo ship, Free Trader or Subsidized Merchant, might load at a Tech Level 15 "A" Class port for delivery to a Tech Level 3 "E" Class port. You have to move the cargo at both ends. A 15,000 pound Rough Terrain Lift Truck is one ungainly beast. Simply saying that you will slap a couple of grav modules on a container does not help at all dealing with the inertial mass of it, and your recipients might not want to have a 20+ ton in mass container dumped on them with no easy way to move it.

 

[Xerxeskingofking]

i remember that I once worked out that the old World Trade Centre towers* were, roughly, 120,000 Dtons or so each.

so most capital shops are in the "very large skyscraper" range.

* chosen mainly because they are big square boxes. 417 m high 63.3984m (208 feet) on each side. 417 x 63.3984 x 63.3984 = 1,676,071.92010752m³. or 119,719.4 Dtons

 

[Rifkin]

When my players ask me questions regarding relative size of objects in dtons, I usually tell them that the luxury Tour buses they see around town (usually a Prevost H3-45) is right around to 9 dtons. These buses are nice clean rectangular boxes with fairly low ground clearance. 13.8m (45ft) long x 2.5m (8.2ft) wide x 3.6m (11.7ft) tall. Comes to 124.2m3 = @9 dtons (8.8 if using 14m3 per dton or 9.2 if using 13.5m3 per dton).

 

[leo knight]

Ken Pick has an excellent article over at Freelance Traveller:

http://www.freelancetraveller.com/features/shipyard/tonnage.html

Hope this helps!

 

[aramis]

20 ft container is approx 4 dtons (it is smaller), a '73 Buick Sportwagon is approx. 2 dTons. Your average 1/2 bath with a shower is around 1/2 a dTon.

A "standard" 1TEU container is 8'x8.5'x20' external dimensions. 1360cf, or 38.5 Cubic meters, 2.75 Td (2.85 in MT). A "high cube" is 9.6' tall, 1520cf, or 43 cubic meters, for 3.07 Td (3.185 in MT).

A 3m ceiling is just about 9' 9.75"... almost 10', but not quite.

A standard 8x12 small bedroom (2.5x3.66m) with a 10' ceiling is roughly 2 Td.

A typical smaller car (12'x6'x4' coupe) fits inside a box of about 8.25 cubic meters, but loses about 1.5 for the above hood and 1 for the above trunk external spaces... so about 1/2 Td. A full sized town car (15' x 7' x 4.5') or about 13.5 cubic meters of bounding box, again, losing about 2/6 for the above trunk and above engine ... so, really, about 1Td.
But also note: shipping them, crated or not, they take about 2x to 3x their volume.

 

[infojunky]

I have a lot of that in my various Transportation and Logistics manuals. Plus, you need to consider in loading vehicles that you will likely have them strapped down quite thoroughly on some form of shipping skid to move them on and off your ship, depending on their size and mass, and your ship configuration. You are not likely to have them packed too tightly, as you need space to strap them down.

Jeeps were routinely shipped two up during ww2, note that 2 stacked jeeps is only a one dTon load. But now most autos are shipped in specialized ships that allow them to roll on and roll of, with the specialized tie downs being part of the ship's infrastructure.

The standard Traveller cargo module, that appears in Supplement 7, Traders and Gunboats, is 3 meters wide, 3 meters high, and 6 meters long, or 4 Traveller dTons. Looking at that from my perspective, that is a bit large for a cargo container, but that is what is given. I would lean towards a cargo module for dense cargo of 1.5 X 1.5 X 3 meters, which is in English terms, just about 5 feet X 5 feet X 10 feet, so 250 cubic feet, or 0.5 Traveller dTons.

Looking at "real world" shipping containers one finds that they don't require much in the way of environmental protection, i.e. stack em on the deck, throw them on a train or truck, the container protects the cargo. So my assumption with Travellers 4 dTon standard containers is that they have to vacuum tight. As such they could be shipped with minimal protection of a hull, external cargo.

I too think that a lot of internal cargo especially in the smaller ships is probably palletized, or in unit load boxes similar to what are used for Air Freight today. I have toyed with various dimensions of standardised boxes, but it generally comes back to the 1.5 meter cube/pallet, a size reasonably handled by small equipment within the shirt sleeve environment of a ship.

The reason that I would like a smaller cargo module for dense cargo, like rations, ore, metal, ammunition, that sort of thing, is handling it is easier. There is no provision in Traveller for what I call materials handling equipment

That really depends on the version of Traveller you play, both GURPs Traveller and T5 have explicit listing of said equipment. I tend to assign a percentage or three of cargo volume to a nebulous title of Cargo Handling, and have done so since I was in the Navy 30 years ago, One UnRep is all it took to point out that was missing. But the real reason it is missing is very few people love the Merchantmen like they love the Warships.

 

[Quint]

Ugh - I had a very nice, erudite response that the computer ate. LOL! in which case I'll simply say thanks to everyone!

D.

 

[WistfulD]

That's why I always hit copy before I hit submit.

What I know about shipping is that things that have to look nice on the other end (goods, vehicles, most anything non-commodity) take an incredible amount of space and prep compaired to, say, grain or crude oil. Even worse for vehicles, although it depends on whether they are in crates, on flight decks, or in docking cradles.

I am now picturing a bunch of vargr or robot teamsters, smoking and leaning against an official Imperium pallet-and-carboard recycling bin.

 

[Timerover51]

Jeeps were routinely shipped two up during ww2, note that 2 stacked jeeps is only a one dTon load.

I am aware of that. I have the vehicle loading for the Liberty Ship and the Victory ship depending on whether the vehicles were on wheels, wheels removed along with canvas covers, and vehicles boxed for re-assembly once the destination is reached. That typically was either Egypt, India, Australia, or the UK. The loading includes the breakdown by cargo hold and deck.

I also have the aircraft loading for both types of ships, assuming that the aircraft were boxed and re-assembled in the Theater of Operations. That was limited to fighter aircraft, as bombers were assumed to be capable of self-deployment.

 

[BlackBat242]

Looking at "real world" shipping containers one finds that they don't require much in the way of environmental protection, i.e. stack em on the deck, throw them on a train or truck, the container protects the cargo. So my assumption with Travellers 4 dTon standard containers is that they have to vacuum tight. As such they could be shipped with minimal protection of a hull, external cargo.

And able to handle temps dropping to near absolute 0? Including the cargo inside them?

There are far more reasons than just a lack of atmosphere for cargo to be carried inside a sealed hull.

 

[infojunky]

And able to handle temps dropping to near absolute 0? Including the cargo inside them?

Just for the sake of argument, why would that even be a concern? Considering the amount of waste heat generated by the transporting ship and the availability of advanced insulation (i.e. the ability to store mass quantities of cryogenic hydrogen next to living compartments within ships). Thermal regulation is reasonably more a issue with vacuum storage at outer systems space stations than starships.

There are far more reasons than just a lack of atmosphere for cargo to be carried inside a sealed hull.

Yes there are for Cargo, but here I was discussing Cargo Containers which should be designed for the rigors of vacuum transport and as such would be designed with set of standard conditions that the contained cargo should expect. Note that they routinely ship refrigerated Containers on ships today with a reasonable expectation that their contents will make it to market.

 

[Timerover51]

Looking at "real world" shipping containers one finds that they don't require much in the way of environmental protection, i.e. stack em on the deck, throw them on a train or truck, the container protects the cargo. So my assumption with Travellers 4 dTon standard containers is that they have to vacuum tight. As such they could be shipped with minimal protection of a hull, external cargo.

In the real world, cargo containers also get washed off of containers ships in high seas. As aside from the mentioned temperature of near absolute zero, you also have significant exposure to radiation in the travel time to and from the planet. Would you like to have a thoroughly irradiated cargo of seeds delivered to you if you were a new agricultural colony, along with having them well frozen?

I too think that a lot of internal cargo especially in the smaller ships is probably palletized, or in unit load boxes similar to what are used for Air Freight today. I have toyed with various dimensions of standardised boxes, but it generally comes back to the 1.5 meter cube/pallet, a size reasonably handled by small equipment within the shirt sleeve environment of a ship.

So, basically, the military's Conex container.

That really depends on the version of Traveller you play, both GURPs Traveller and T5 have explicit listing of said equipment. I tend to assign a percentage or three of cargo volume to a nebulous title of Cargo Handling, and have done so since I was in the Navy 30 years ago, One UnRep is all it took to point out that was missing. But the real reason it is missing is very few people love the Merchantmen like they love the Warships.

Warships without some means of materials handling equipment in this day of Vertical Replenishment are a contradiction of terms. Either that, or they do not receive any package weighing more than about 50 to 75 pounds. That does significantly limit what can be delivered. All Aircraft Carriers have material handling equipment. As for Traveller Warships, given the extreme size of the ones in the Big Ship Universe, they are going to need some form of material handling equipment, or have their crews spend a lot of time moving supplies about.

 

[BillDowns]

One comment about the TEU containers Aramis mentioned, as I recall, they have a weight limit also. I think 32 tons for the small ones, and maybe around 37 for the big ones.

 

[Timerover51]

I looked up the loading capacity of the standard World War 2 Liberty ship in terms of jeeps and various aircraft. The ship did have to have enlarged hatches to carry aircraft, so was given a separate designation of ZEC-5.

The standard Liberty could carry 498 1/4 Ton Jeeps on wheels, or 2078 crated Jeeps, with the number of Jeeps on wheels doubled if they were stacked.

The Modified Liberty, ZEC-5 with enlarged hatches could carry the following number of aircraft of different types. The P-51 and the P-47 had the stabilizers, wing tips, and propellers removed. The P-80, better known as the F-80 Shooting Star, had the empennage (the tail assembly) and motor separately boxed.

P-51 Mustang, 65 units.
P-47D Thunderbolt, 41 units,
P-47N, a very long range version of the Thunderbolt, 37 units
P-80 Shooting Star, 45 units

In both the Jeep and aircraft loading, the limitation is volume, not weight. The maximum load for a Liberty with maximum fuel was 8,000 dead weight long tons of cargo.

Figuring the Jeeps on wheels at about 1.25 tons, so about 625 tons dead weight for one layer, and allowing 1.5 tons for stacked (additional dunnage needed for stacking), it would be about 1250 tons or so. Allowing 1.5 tons for crated Jeeps, it would be about 3120 dead weight long tons.

For the aircraft, allow about 5 tons for the P-51, and about 6 tons for the P-47 models and the P-80, it would be about 325 tons for the Mustang, 246 tons or 222 tons for the Thunderbolts, and 270 tons for the Shooting Star. That would basically be a "light ship" loading, and the Liberty probably would need some additional ballast for stability.

 

[phavoc]

I would assume there would be three types of containers. A standard one for regular in atmosphere transport, like a regular semi, a second version similar to a sea transport container that can hold an atmosphere for say 24hors before it begins to be compromised, and a third type designed with vacuum and radiation in mind, essentially built with the same materials as a spacecraft (under 100tons).

The middle of the road is perfect to be unloaded in orbit and ferried down. The first one is loaded on the surface or through airlocks. And the space rated one can be carried or stored anywhere, kind of like that one ship in battlestar galactic that always looked like a container transport ship.

 

[infojunky]

I would assume there would be three types of containers. A standard one for regular in atmosphere transport, like a regular semi, a second version similar to a sea transport container that can hold an atmosphere for say 24 hrs before it begins to be compromised, and a third type designed with vacuum and radiation in mind, essentially built with the same materials as a spacecraft (under 100 tons).

Mostly the system you describe blows the advantages of the Inter-modal Containers out of the water. In that the unitary load moves through each environment/mode of transport without having to be unloaded.

I am not against a larger Ship scale container that is essentially a ship hull pod. I have considered the 50 dTon and/or 100 dTon bays as the basic shapes for said containers. In that that there have been some indication that the weapons that fit in those bays are largely interchangeable.

 

[Timerover51]

I would assume there would be three types of containers. A standard one for regular in atmosphere transport, like a regular semi, a second version similar to a sea transport container that can hold an atmosphere for say 24hors before it begins to be compromised, and a third type designed with vacuum and radiation in mind, essentially built with the same materials as a spacecraft (under 100tons).

The middle of the road is perfect to be unloaded in orbit and ferried down. The first one is loaded on the surface or through airlocks. And the space rated one can be carried or stored anywhere, kind of like that one ship in battlestar galactic that always looked like a container transport ship.

The whole idea of containers is a cheap means of shipping, with the ability to drop it off and pick it up latter, while it can be transported by truck or train as well. Depending on how heavy you view spacecraft hulls, a container built to under 100 dTons spacecraft standard is neither going to be cheap or light, and clearly is subject to being modified into a space craft. As a first cut, a circa 100 dTon hull is going to weigh about 140 to 175 mass tons or so.

 

[phavoc]

Mostly the system you describe blows the advantages of the Inter-modal Containers out of the water. In that the unitary load moves through each environment/mode of transport without having to be unloaded.

I am not against a larger Ship scale container that is essentially a ship hull pod. I have considered the 50 dTon and/or 100 dTon bays as the basic shapes for said containers. In that that there have been some indication that the weapons that fit in those bays are largely interchangeable.

How so? What I stated is exactly how it is today. Today's modern containers are comprised of two types - ocean going, which are characterized by their external appearance, and non-ocean going, which are indistinguishable from the containers that are built into the frames of trucks and trailers. The addition of the hazards of space would naturally mean a third type would be necessary to deal with radiation, micro-metoroids, etc.

What you are referring to is more of the LASH (Lighter Aboard Ship) idea that came about in the 70s, where mini-barges were hoisted on to the ship that could then be distributed elsewhere via water after they had been transported across the ocean. There's nothing to say that this wouldn't work in the Traveller universe. Having a large container that held say 50 to 100 other smaller containers would allow for the expensive ship to arrive in-system at the 100D limit, drop off the larger container that has the cargo destined for this system, refuel and pickup new ones and then jump out. It would shave days off a normal port rendezvous process.