[Traveller Answer] Starship Hulls

Date: Mon, 4 Nov 96 22:27:00 -0500
From: Derek Wildstar <wildstar@qrc.com>
Subject: [Traveller Answer] Starship Hulls

In a previous Traveller Answer I said:

To repeat: You can IGNORE all reference to surface area requirements for power plants in QSDS. Sorry, folks.

Wow, that is a really big change! Now I can actually design TL9 ships

Yes; and big military ships (over 5,000 tons) become possible again, too. The problem appeared when we tried to design ships at the top end of the QSDS range, or even bigger.

Seriously though, will there be any requirement for surafce area for fusion pl ants?

Starship fusion plants will (almost certainly) not require surface area. Vehicle-type fusion plants require surface area, and will require a lot of if if they are installed on space vehicles. The precise rules will appear in the vehicle design rules of the forthcoming _Central Supply Catalog_ by Greg Porter.

Do external mounts add to the ship's tonnage (ie a 1000 ton ship with an external fighter is 1010, or is a 1000 ton ship with a fighter actually only 990 tons)

You can work it either way. Since QSDS doesn't include any 990 ton hulls, use a 1000 ton hull and only put 990 tons of stuff[*] into it. The difference between the 1000-ton QSDS hull and a custom-made 990 ton hull is minor - and more than compensated for by the QSDS round-off and the QSDS discount.

The alternative is to put 1000 tons of stuff in a 1000-ton hull, and hang the fighter outside - the result being a 1010-ton ship, and you'd have to use the next larger size drives. Unless your external craft is large, you're probably better off with the first option. The second option is useful for ships that carry large loads in grapples.

* "Stuff" is a technical term for "anything that you'd ordinarily put in a starship, except for the fighter that you're hanging outside". ;-)

Aren't the external mounts a tad greedy on the surface area? A 30 ton ship requires more surface than is available to an entire 200 ton starship

Just a little; in the detailed design system, the area required by a grapple is determined by the overall length of the ship that will use that grapple. Since, in QSDS in particular, there's no good way of knowing what specific ship will be used by each grapple, the grapples are "generic" - they're designed for the longest and widest ship possible.

SO, for most craft the grapple will be used to hold, the grapple will be using more surface area than is needed. Think of it this way - if you design a grapple to hold just one specific design of ship, it can be a lot smaller. But the QSDS grapples are designed to hold _any_ ship of that tonnage and so are a bit more complex, and a lot bigger, then they absolutely have to be.

How did you calculate structure? I have figured out everything else (hull-wise) for conversion from FF&S, but that is just to much for me brain

The structure computation is a little non-obvious, and I don't recall ever posting (at least on the TML) how it's done. TO figure out structure, multiply the ship's size (in displacement tons) by it's maximum G rating (in Gs). Convert the result using the Battle Rider factor conversion chart, and that's structure.

Consequently, to "beef up" a ship's structure (for a military vessel, for example), increase it's Max G rating beyond the minimum you need to maneuver the vessel safely.

Here's a fragment of the Battle Rider table that'll be most useful in figuring out structure values for QSDS-sized hulls:

Value	Factor
80	3
120	4
160	5
200	6
250	7
300	8
400	9
500	10
750	11
1000	12
1250	13
1500	14
1750	15
2000	16
2500	17
3000	18
3500	19
4000	20
4500	21
5000	22
6000	23
7000	24
8000	25
9000	26
10000	27

Thus, a 100-ton ship with a structure rated for 6g would have a Structure rating of 10.

Guy "wildstar" Garnett
Traveller Answer Team

wildstar@qrc.com
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