Shipyard Construction Rate

[MasterGwydion]

This is not directly an answer to the question posed in the original post, but I thought you might find it interesting nonetheless;

The linearity of ship construction if strictly following the HG2022 rules bothered me a lil' bit — sure, larger ships take more time to build, but one needs to take into account that a lot of the effort of building a ship is its hull, and when it comes to hulls, the square-cube law comes into play; if you quadruple the volume of an object whilst maintaining its shape, its surface area will only have increase by a factor of 2. So, in theory, if you were to make a copy of a 100 dTon ship, but four times bigger at 400 dTons, its surface area would only be twice as large and the construction time would be somewhere between 2 and 4 times as long.

Following that line of reasoning, I concocted the following house rule: the actual construction time of a ship is given by assuming the base 1MCr/Day construction rate, which is then multiplied by a size factor that is calculated as: 10 * (√x)/x, where 'x' is the ship's tonnage. For ships of 100 dTons, this modifier is exactly 1.

So as an example, using the rules as-written in the High Guard 2022 book, a Beowulf-class Type-A Free Trader, which costs MCr46.242 and is a TL12 ships (Construction Time Reduction of 90%) would take 46.242 * 0.9 = 41.6178 days to build.
Using the above house rule, it'd take that same time but multiplied by a factor of 10 * √200/200 = ~0.7071 so the construction time would be 41.6178 * 0.7071 = ~29.4279 days, or just shy of a month*.
*Be that the Imperial Calendar 28-day 'month' or the real-world 30-day month.

Applying the same maths to a much larger ship, such as a Tigress:
A MCr356830.9335, TL15 ship would, rules-as-written, take 356830.9335 * 0.6 = 214098.5601 days; in other words, about half a millennium and a few decades. Even with the additional 90% reduction for modular construction of ships of 50,000 or more dTons would only bring that down to 58.6 years.
Using the house rule, we find that the Tigress would have a size multiplier of 10 * √500000/500000 = ~0.01414213562, so its construction time would be 214098.5601 * 0.01414213562 = 3027.81087298 days, or some 8.3 years. If using the modular construction reduction as well, it'd bring it down to 302 days.

Amusingly, this houserule brings construction times much more in-line, although not exactly so, to the ship construction times as given in Classic Traveller modules (a Tigress took some 56 months to build according to Supplement 9: Fighting Ships if singly, and 40 in quantity).

Edit: As a further exploration of this houserule; for ships under 100 dTons, the multiplier is actually larger than one, so it implies it takes more time to construct a small craft than the straight '1 Day per MCr' rule would imply. This has some interesting consequences:

A Shuttle (95 tons, MCr14.6745, TL12) would take 14.6745 * 0.9 * (10 * √95/95) = ~13.55 days to build under the houserule.
A Light Fighter (10 tons, MCr9.432, TL12) would take 9.432 * 0.9 * (10 * sqrt(10)/10) = ~26.844 days to build.

At first it might be confusing for a craft that's one-fifth the size of the other to take nearly twice as long to build, but I actually find this quite reasonable; one's a military-spec craft built to more exacting tolerances, whereas the other is a glorified flying tin can.

Yeah. The math killed Me, but this was well explained. How does the 3I build Tigress-class ships? Do they spend 58.6 years building every ship? If so, then We definitely need to revisit the ship construction math, but using the inverse square method and using your equation is way more math than I tend to want. It does work though, or seems to work anyhow. I figure on something as small as 10-ton fighters, you are better off just using a Fabricator. A very big fabricator. The kind only corps and governments can afford. Like somewhere around 250 at TL-15 for a fabricator that can build 10-ton fighters in a few hours.

 

[GabrielGABFonseca]

Yeah. The math killed Me, but this was well explained. How does the 3I build Tigress-class ships? Do they spend 58.6 years building every ship? If so, then We definitely need to revisit the ship construction math, but using the inverse square method and using your equation is way more math than I tend to want. It does work though, or seems to work anyhow. I figure on something as small as 10-ton fighters, you are better off just using a Fabricator. A very big fabricator. The kind only corps and governments can afford. Like somewhere around 250 at TL-15 for a fabricator that can build 10-ton fighters in a few hours.

I think if this house rule were to become A Thing™, the way to go would likely be to turn it into a table relating different ships sizes to their respective modifiers, which makes it accessible to everyone.
Could include the formula too, for those who want to brave it, but the table should probably suffice.

 

[phavoc]

In late 1916, two British destroyers of the 6th Flotilla in the Dover Patrol—Nubian and Zulu—were badly damaged by German attacks in the English Channel. Nubian's bow had been destroyed by a torpedo from a German torpedo boat on 27 October in the Battle of Dover Strait, while Zulu had her stern blown off by a mine in the Channel on 8 November, and was towed to Calais.[3] Both wrecks were then towed to Chatham Dockyard, where a complete destroyer was constructed by joining the foreparts of Zulu with the stern of Nubian,[4] and despite a 3.5 inches (89 mm) difference in beam,[2] the unique operation was successful.[5] The ship was renamed Zubian by Admiral Reginald Bacon, the commander of the Dover Patrol.[6] The hybrid destroyer was commissioned on 7 June 1917.[7] The choice of name caused confusion among the German Imperial Admiralty Staff, who knew of no such ship under construction.[8]

USN did similar thing multiple times, though I don't believe they did that much of a difference.

Fortunate the RN destroyers of the period were fairly simple and unarmed. Not sure you could have done the same with a bigger ship, let alone an armored one like a CA or even a CL.

 

[phavoc]

Bridge: Yes.

Multiple Yard/bays: Yes, and I'd call it the norm for larger ships.
Multiple bays working on a ship IS the best way to beat the 1MCr per day limit... but you'd either need to own the yards or pay them for the expedited service.

That's an interesting question. It's purely academic but one would expect a shipyard building a big ship to do that already, as one would expect a buyer to want that done to get their ship in a timely manner.

The shipyard was be able to build more ships rather than labor longer on a single hull. That seems more profitable (more ships rather than fewer).

This is probably a good example where the building rules don't scale up well from adventure class ships to capital class, or the mega freighters.

 

[Condottiere]

Ship components are likely manufactured in factories.

The yards are system integrators.

 

[Arkathan]

That's an interesting question. It's purely academic but one would expect a shipyard building a big ship to do that already, as one would expect a buyer to want that done to get their ship in a timely manner.

The shipyard was be able to build more ships rather than labor longer on a single hull. That seems more profitable (more ships rather than fewer).

This is probably a good example where the building rules don't scale up well from adventure class ships to capital class, or the mega freighters.

Build rates are a known quantity. Corporations factor this into their scheduled ship buys.
A shipyard will want to have as many contracts to build in hand as they can get. Which means as many bays as they can use. Making a client wait could mean that the shipyard three parsecs away gets the contract. A bird in the hand...
The potential for that lost contract incentivize the yard to make speedy construction a premium service.
Now, a bulk contract would make sense to devote several yards to making one ship at a time so that the client can ease their crew staffing in as opposed to staffing ten ships at once after a year or more of production.

 

[Arkathan]

Ship components are likely manufactured in factories.

The yards are system integrators.

Fabricators change the dynamic, with the potential for licensed templates and royalties paid for each print, or as a subscription.
The "factory" could then be on the shipyard and not tied to the parent company.

 

[Condottiere]

Hulls can also be constructed additively.

 

[MasterGwydion]

Hulls can also be constructed additively.

That would be a fabricator. I am not sure where I read it, but in one of the books it says, starship hulls cannot be built using fabricators. Hulls must be built using a heavy industry manufacturing process. Sad, but true.

 

[Arkathan]

Hulls can also be constructed additively.

Hulls can be constructed in sections and welded together.

 

[Terry Mixon]

If a fabricator recreates things to a molecular level, I can't imagine why it wouldn't work so long as the entire hull is created at once. Wouldn't work for something big under the rules you mentioned, but a monster fabricator should be able to churn out small craft. That's how I'd play it.

 

[MasterGwydion]

If a fabricator recreates things to a molecular level, I can't imagine why it wouldn't work so long as the entire hull is created at once. Wouldn't work for something big under the rules you mentioned, but a monster fabricator should be able to churn out small craft. That's how I'd play it.

I would too, just because it makes sense to Me. I will have to look for the rule. I think it may have been in one of the books Geir wrote.

 

[Condottiere]

Depends what material they would use to construct a zero percent volume hull.

With bonded superdense hull armour, it might require baking.

 

[MasterGwydion]

Depends what material they would use to construct a zero percent volume hull.

With bonded superdense hull armour, it might require baking.

Actually, doesn't bonded superdense require being compacted by gravity generators? That may explain why it can't be Fabricated.

 

[Geir]

I would too, just because it makes sense to Me. I will have to look for the rule. I think it may have been in one of the books Geir wrote.

I hope I didn't write you cannot do it, because the basic premise for fabricators is that they can create just about anything at TL-2, so a TL15 fabricator should be able to build a TL13 ship - if it was big enough or used external fabrication (at TL-3).

 

[MasterGwydion]

I hope I didn't write you cannot do it, because the basic premise for fabricators is that they can create just about anything at TL-2, so a TL15 fabricator should be able to build a TL13 ship - if it was big enough or used external fabrication (at TL-3).

It could have been saying that it couldn't make Bonded Superdense Hulls, because of the TL issue, but lower TL hulls are fine.

 

[Condottiere]

Hull armour, yes.

Exceptionally, titanium steel.

Hull itself, don't really know.

 

[MasterGwydion]

Hull armour, yes.

Exceptionally, titanium steel.

Hull itself, don't really know.

Isn't the hull exterior made out of the same stuff as the armor, just thinner?

 

[Condottiere]

Probably by default of the technologiocal level stated the spacecraft was constructed at.

But if no benefits (or penalties) are attached to that (for the hull), it could be stainless steel.

 

[Sigtrygg]

My headcanon has crystaliron hulls grown in a controlled gravitics environment.

For superdense and bonded superdense damper tech is involved. MT mentions coherent superdense at TL17ish IIRC, will check that one.